1344 lines
40 KiB
C
1344 lines
40 KiB
C
/*-
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* Copyright (c) 1982, 1986, 1991, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)kern_clock.c 8.5 (Berkeley) 1/21/94
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* $Id: kern_clock.c,v 1.42 1997/09/24 16:39:16 gibbs Exp $
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*/
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/* Portions of this software are covered by the following: */
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/******************************************************************************
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* *
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* Copyright (c) David L. Mills 1993, 1994 *
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* *
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* Permission to use, copy, modify, and distribute this software and its *
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* documentation for any purpose and without fee is hereby granted, provided *
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* that the above copyright notice appears in all copies and that both the *
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* copyright notice and this permission notice appear in supporting *
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* documentation, and that the name University of Delaware not be used in *
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* advertising or publicity pertaining to distribution of the software *
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* without specific, written prior permission. The University of Delaware *
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* makes no representations about the suitability this software for any *
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* purpose. It is provided "as is" without express or implied warranty. *
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* *
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*****************************************************************************/
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#include "opt_cpu.h" /* XXX */
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/dkstat.h>
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#include <sys/callout.h>
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#include <sys/kernel.h>
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#include <sys/proc.h>
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#include <sys/resourcevar.h>
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#include <sys/signalvar.h>
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#include <sys/timex.h>
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#include <vm/vm.h>
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#include <sys/lock.h>
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#include <vm/pmap.h>
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#include <vm/vm_map.h>
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#include <sys/sysctl.h>
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#include <machine/cpu.h>
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#define CLOCK_HAIR /* XXX */
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#include <machine/clock.h>
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#include <machine/limits.h>
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#ifdef GPROF
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#include <sys/gmon.h>
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#endif
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static void initclocks __P((void *dummy));
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SYSINIT(clocks, SI_SUB_CLOCKS, SI_ORDER_FIRST, initclocks, NULL)
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/* Exported to machdep.c. */
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struct callout *callout;
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struct callout_list callfree;
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int callwheelsize, callwheelbits, callwheelmask;
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struct callout_tailq *callwheel;
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/* Some of these don't belong here, but it's easiest to concentrate them. */
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static long cp_time[CPUSTATES];
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long dk_seek[DK_NDRIVE];
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static long dk_time[DK_NDRIVE]; /* time busy (in statclock ticks) */
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long dk_wds[DK_NDRIVE];
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long dk_wpms[DK_NDRIVE];
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long dk_xfer[DK_NDRIVE];
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int dk_busy;
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int dk_ndrive = 0;
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char dk_names[DK_NDRIVE][DK_NAMELEN];
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long tk_cancc;
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long tk_nin;
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long tk_nout;
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long tk_rawcc;
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/*
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* Clock handling routines.
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*
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* This code is written to operate with two timers that run independently of
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* each other. The main clock, running hz times per second, is used to keep
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* track of real time. The second timer handles kernel and user profiling,
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* and does resource use estimation. If the second timer is programmable,
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* it is randomized to avoid aliasing between the two clocks. For example,
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* the randomization prevents an adversary from always giving up the cpu
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* just before its quantum expires. Otherwise, it would never accumulate
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* cpu ticks. The mean frequency of the second timer is stathz.
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*
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* If no second timer exists, stathz will be zero; in this case we drive
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* profiling and statistics off the main clock. This WILL NOT be accurate;
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* do not do it unless absolutely necessary.
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*
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* The statistics clock may (or may not) be run at a higher rate while
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* profiling. This profile clock runs at profhz. We require that profhz
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* be an integral multiple of stathz.
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*
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* If the statistics clock is running fast, it must be divided by the ratio
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* profhz/stathz for statistics. (For profiling, every tick counts.)
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*/
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/*
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* TODO:
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* allocate more timeout table slots when table overflows.
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*/
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/*
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* Bump a timeval by a small number of usec's.
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*/
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#define BUMPTIME(t, usec) { \
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register volatile struct timeval *tp = (t); \
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register long us; \
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\
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tp->tv_usec = us = tp->tv_usec + (usec); \
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if (us >= 1000000) { \
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tp->tv_usec = us - 1000000; \
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tp->tv_sec++; \
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} \
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}
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int stathz;
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int profhz;
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static int profprocs;
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int ticks;
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static int softticks; /* Like ticks, but for softclock(). */
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static struct callout *nextsoftcheck; /* Next callout to be checked. */
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static int psdiv, pscnt; /* prof => stat divider */
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int psratio; /* ratio: prof / stat */
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volatile struct timeval time;
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volatile struct timeval mono_time;
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/*
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* Phase/frequency-lock loop (PLL/FLL) definitions
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*
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* The following variables are read and set by the ntp_adjtime() system
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* call.
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*
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* time_state shows the state of the system clock, with values defined
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* in the timex.h header file.
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*
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* time_status shows the status of the system clock, with bits defined
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* in the timex.h header file.
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*
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* time_offset is used by the PLL/FLL to adjust the system time in small
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* increments.
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*
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* time_constant determines the bandwidth or "stiffness" of the PLL.
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*
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* time_tolerance determines maximum frequency error or tolerance of the
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* CPU clock oscillator and is a property of the architecture; however,
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* in principle it could change as result of the presence of external
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* discipline signals, for instance.
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*
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* time_precision is usually equal to the kernel tick variable; however,
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* in cases where a precision clock counter or external clock is
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* available, the resolution can be much less than this and depend on
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* whether the external clock is working or not.
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*
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* time_maxerror is initialized by a ntp_adjtime() call and increased by
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* the kernel once each second to reflect the maximum error
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* bound growth.
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*
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* time_esterror is set and read by the ntp_adjtime() call, but
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* otherwise not used by the kernel.
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*/
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int time_status = STA_UNSYNC; /* clock status bits */
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int time_state = TIME_OK; /* clock state */
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long time_offset = 0; /* time offset (us) */
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long time_constant = 0; /* pll time constant */
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long time_tolerance = MAXFREQ; /* frequency tolerance (scaled ppm) */
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long time_precision = 1; /* clock precision (us) */
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long time_maxerror = MAXPHASE; /* maximum error (us) */
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long time_esterror = MAXPHASE; /* estimated error (us) */
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/*
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* The following variables establish the state of the PLL/FLL and the
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* residual time and frequency offset of the local clock. The scale
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* factors are defined in the timex.h header file.
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*
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* time_phase and time_freq are the phase increment and the frequency
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* increment, respectively, of the kernel time variable at each tick of
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* the clock.
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*
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* time_freq is set via ntp_adjtime() from a value stored in a file when
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* the synchronization daemon is first started. Its value is retrieved
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* via ntp_adjtime() and written to the file about once per hour by the
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* daemon.
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*
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* time_adj is the adjustment added to the value of tick at each timer
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* interrupt and is recomputed from time_phase and time_freq at each
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* seconds rollover.
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*
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* time_reftime is the second's portion of the system time on the last
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* call to ntp_adjtime(). It is used to adjust the time_freq variable
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* and to increase the time_maxerror as the time since last update
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* increases.
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*/
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static long time_phase = 0; /* phase offset (scaled us) */
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long time_freq = 0; /* frequency offset (scaled ppm) */
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static long time_adj = 0; /* tick adjust (scaled 1 / hz) */
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static long time_reftime = 0; /* time at last adjustment (s) */
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#ifdef PPS_SYNC
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/*
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* The following variables are used only if the kernel PPS discipline
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* code is configured (PPS_SYNC). The scale factors are defined in the
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* timex.h header file.
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*
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* pps_time contains the time at each calibration interval, as read by
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* microtime(). pps_count counts the seconds of the calibration
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* interval, the duration of which is nominally pps_shift in powers of
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* two.
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*
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* pps_offset is the time offset produced by the time median filter
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* pps_tf[], while pps_jitter is the dispersion (jitter) measured by
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* this filter.
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*
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* pps_freq is the frequency offset produced by the frequency median
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* filter pps_ff[], while pps_stabil is the dispersion (wander) measured
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* by this filter.
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*
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* pps_usec is latched from a high resolution counter or external clock
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* at pps_time. Here we want the hardware counter contents only, not the
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* contents plus the time_tv.usec as usual.
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*
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* pps_valid counts the number of seconds since the last PPS update. It
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* is used as a watchdog timer to disable the PPS discipline should the
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* PPS signal be lost.
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*
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* pps_glitch counts the number of seconds since the beginning of an
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* offset burst more than tick/2 from current nominal offset. It is used
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* mainly to suppress error bursts due to priority conflicts between the
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* PPS interrupt and timer interrupt.
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*
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* pps_intcnt counts the calibration intervals for use in the interval-
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* adaptation algorithm. It's just too complicated for words.
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*/
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struct timeval pps_time; /* kernel time at last interval */
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long pps_offset = 0; /* pps time offset (us) */
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long pps_jitter = MAXTIME; /* pps time dispersion (jitter) (us) */
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long pps_tf[] = {0, 0, 0}; /* pps time offset median filter (us) */
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long pps_freq = 0; /* frequency offset (scaled ppm) */
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long pps_stabil = MAXFREQ; /* frequency dispersion (scaled ppm) */
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long pps_ff[] = {0, 0, 0}; /* frequency offset median filter */
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long pps_usec = 0; /* microsec counter at last interval */
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long pps_valid = PPS_VALID; /* pps signal watchdog counter */
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int pps_glitch = 0; /* pps signal glitch counter */
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int pps_count = 0; /* calibration interval counter (s) */
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int pps_shift = PPS_SHIFT; /* interval duration (s) (shift) */
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int pps_intcnt = 0; /* intervals at current duration */
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/*
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* PPS signal quality monitors
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*
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* pps_jitcnt counts the seconds that have been discarded because the
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* jitter measured by the time median filter exceeds the limit MAXTIME
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* (100 us).
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*
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* pps_calcnt counts the frequency calibration intervals, which are
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* variable from 4 s to 256 s.
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*
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* pps_errcnt counts the calibration intervals which have been discarded
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* because the wander exceeds the limit MAXFREQ (100 ppm) or where the
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* calibration interval jitter exceeds two ticks.
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*
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* pps_stbcnt counts the calibration intervals that have been discarded
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* because the frequency wander exceeds the limit MAXFREQ / 4 (25 us).
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*/
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long pps_jitcnt = 0; /* jitter limit exceeded */
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long pps_calcnt = 0; /* calibration intervals */
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long pps_errcnt = 0; /* calibration errors */
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long pps_stbcnt = 0; /* stability limit exceeded */
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#endif /* PPS_SYNC */
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/* XXX none of this stuff works under FreeBSD */
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#ifdef EXT_CLOCK
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/*
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* External clock definitions
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*
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* The following definitions and declarations are used only if an
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* external clock (HIGHBALL or TPRO) is configured on the system.
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*/
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#define CLOCK_INTERVAL 30 /* CPU clock update interval (s) */
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/*
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* The clock_count variable is set to CLOCK_INTERVAL at each PPS
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* interrupt and decremented once each second.
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*/
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int clock_count = 0; /* CPU clock counter */
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#ifdef HIGHBALL
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/*
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* The clock_offset and clock_cpu variables are used by the HIGHBALL
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* interface. The clock_offset variable defines the offset between
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* system time and the HIGBALL counters. The clock_cpu variable contains
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* the offset between the system clock and the HIGHBALL clock for use in
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* disciplining the kernel time variable.
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*/
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extern struct timeval clock_offset; /* Highball clock offset */
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long clock_cpu = 0; /* CPU clock adjust */
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#endif /* HIGHBALL */
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#endif /* EXT_CLOCK */
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/*
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* hardupdate() - local clock update
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*
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* This routine is called by ntp_adjtime() to update the local clock
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* phase and frequency. The implementation is of an adaptive-parameter,
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* hybrid phase/frequency-lock loop (PLL/FLL). The routine computes new
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* time and frequency offset estimates for each call. If the kernel PPS
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* discipline code is configured (PPS_SYNC), the PPS signal itself
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* determines the new time offset, instead of the calling argument.
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* Presumably, calls to ntp_adjtime() occur only when the caller
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* believes the local clock is valid within some bound (+-128 ms with
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* NTP). If the caller's time is far different than the PPS time, an
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* argument will ensue, and it's not clear who will lose.
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*
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* For uncompensated quartz crystal oscillatores and nominal update
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* intervals less than 1024 s, operation should be in phase-lock mode
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* (STA_FLL = 0), where the loop is disciplined to phase. For update
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* intervals greater than thiss, operation should be in frequency-lock
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* mode (STA_FLL = 1), where the loop is disciplined to frequency.
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*
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* Note: splclock() is in effect.
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*/
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void
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hardupdate(offset)
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long offset;
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{
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long ltemp, mtemp;
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if (!(time_status & STA_PLL) && !(time_status & STA_PPSTIME))
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return;
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ltemp = offset;
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#ifdef PPS_SYNC
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if (time_status & STA_PPSTIME && time_status & STA_PPSSIGNAL)
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ltemp = pps_offset;
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#endif /* PPS_SYNC */
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/*
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* Scale the phase adjustment and clamp to the operating range.
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*/
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if (ltemp > MAXPHASE)
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time_offset = MAXPHASE << SHIFT_UPDATE;
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else if (ltemp < -MAXPHASE)
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time_offset = -(MAXPHASE << SHIFT_UPDATE);
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else
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time_offset = ltemp << SHIFT_UPDATE;
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/*
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* Select whether the frequency is to be controlled and in which
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* mode (PLL or FLL). Clamp to the operating range. Ugly
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* multiply/divide should be replaced someday.
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*/
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if (time_status & STA_FREQHOLD || time_reftime == 0)
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time_reftime = time.tv_sec;
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mtemp = time.tv_sec - time_reftime;
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time_reftime = time.tv_sec;
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if (time_status & STA_FLL) {
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if (mtemp >= MINSEC) {
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ltemp = ((time_offset / mtemp) << (SHIFT_USEC -
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SHIFT_UPDATE));
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if (ltemp < 0)
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time_freq -= -ltemp >> SHIFT_KH;
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else
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time_freq += ltemp >> SHIFT_KH;
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}
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} else {
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if (mtemp < MAXSEC) {
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ltemp *= mtemp;
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if (ltemp < 0)
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time_freq -= -ltemp >> (time_constant +
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time_constant + SHIFT_KF -
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SHIFT_USEC);
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else
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time_freq += ltemp >> (time_constant +
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time_constant + SHIFT_KF -
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SHIFT_USEC);
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}
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}
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if (time_freq > time_tolerance)
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time_freq = time_tolerance;
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else if (time_freq < -time_tolerance)
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time_freq = -time_tolerance;
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}
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/*
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* Initialize clock frequencies and start both clocks running.
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*/
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/* ARGSUSED*/
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static void
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initclocks(dummy)
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void *dummy;
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{
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register int i;
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/*
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* Set divisors to 1 (normal case) and let the machine-specific
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* code do its bit.
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*/
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psdiv = pscnt = 1;
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cpu_initclocks();
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/*
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* Compute profhz/stathz, and fix profhz if needed.
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*/
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i = stathz ? stathz : hz;
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if (profhz == 0)
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profhz = i;
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psratio = profhz / i;
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}
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/*
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* The real-time timer, interrupting hz times per second.
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*/
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void
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hardclock(frame)
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register struct clockframe *frame;
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{
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register struct proc *p;
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p = curproc;
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if (p) {
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register struct pstats *pstats;
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/*
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* Run current process's virtual and profile time, as needed.
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*/
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pstats = p->p_stats;
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if (CLKF_USERMODE(frame) &&
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timerisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value) &&
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itimerdecr(&pstats->p_timer[ITIMER_VIRTUAL], tick) == 0)
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psignal(p, SIGVTALRM);
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if (timerisset(&pstats->p_timer[ITIMER_PROF].it_value) &&
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itimerdecr(&pstats->p_timer[ITIMER_PROF], tick) == 0)
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psignal(p, SIGPROF);
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}
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/*
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* If no separate statistics clock is available, run it from here.
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*/
|
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if (stathz == 0)
|
|
statclock(frame);
|
|
|
|
/*
|
|
* Increment the time-of-day.
|
|
*/
|
|
ticks++;
|
|
{
|
|
int time_update;
|
|
struct timeval newtime = time;
|
|
long ltemp;
|
|
|
|
if (timedelta == 0) {
|
|
time_update = CPU_THISTICKLEN(tick);
|
|
} else {
|
|
time_update = CPU_THISTICKLEN(tick) + tickdelta;
|
|
timedelta -= tickdelta;
|
|
}
|
|
BUMPTIME(&mono_time, time_update);
|
|
|
|
/*
|
|
* Compute the phase adjustment. If the low-order bits
|
|
* (time_phase) of the update overflow, bump the high-order bits
|
|
* (time_update).
|
|
*/
|
|
time_phase += time_adj;
|
|
if (time_phase <= -FINEUSEC) {
|
|
ltemp = -time_phase >> SHIFT_SCALE;
|
|
time_phase += ltemp << SHIFT_SCALE;
|
|
time_update -= ltemp;
|
|
}
|
|
else if (time_phase >= FINEUSEC) {
|
|
ltemp = time_phase >> SHIFT_SCALE;
|
|
time_phase -= ltemp << SHIFT_SCALE;
|
|
time_update += ltemp;
|
|
}
|
|
|
|
newtime.tv_usec += time_update;
|
|
/*
|
|
* On rollover of the second the phase adjustment to be used for
|
|
* the next second is calculated. Also, the maximum error is
|
|
* increased by the tolerance. If the PPS frequency discipline
|
|
* code is present, the phase is increased to compensate for the
|
|
* CPU clock oscillator frequency error.
|
|
*
|
|
* On a 32-bit machine and given parameters in the timex.h
|
|
* header file, the maximum phase adjustment is +-512 ms and
|
|
* maximum frequency offset is a tad less than) +-512 ppm. On a
|
|
* 64-bit machine, you shouldn't need to ask.
|
|
*/
|
|
if (newtime.tv_usec >= 1000000) {
|
|
newtime.tv_usec -= 1000000;
|
|
newtime.tv_sec++;
|
|
time_maxerror += time_tolerance >> SHIFT_USEC;
|
|
|
|
/*
|
|
* Compute the phase adjustment for the next second. In
|
|
* PLL mode, the offset is reduced by a fixed factor
|
|
* times the time constant. In FLL mode the offset is
|
|
* used directly. In either mode, the maximum phase
|
|
* adjustment for each second is clamped so as to spread
|
|
* the adjustment over not more than the number of
|
|
* seconds between updates.
|
|
*/
|
|
if (time_offset < 0) {
|
|
ltemp = -time_offset;
|
|
if (!(time_status & STA_FLL))
|
|
ltemp >>= SHIFT_KG + time_constant;
|
|
if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE)
|
|
ltemp = (MAXPHASE / MINSEC) <<
|
|
SHIFT_UPDATE;
|
|
time_offset += ltemp;
|
|
time_adj = -ltemp << (SHIFT_SCALE - SHIFT_HZ -
|
|
SHIFT_UPDATE);
|
|
} else {
|
|
ltemp = time_offset;
|
|
if (!(time_status & STA_FLL))
|
|
ltemp >>= SHIFT_KG + time_constant;
|
|
if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE)
|
|
ltemp = (MAXPHASE / MINSEC) <<
|
|
SHIFT_UPDATE;
|
|
time_offset -= ltemp;
|
|
time_adj = ltemp << (SHIFT_SCALE - SHIFT_HZ -
|
|
SHIFT_UPDATE);
|
|
}
|
|
|
|
/*
|
|
* Compute the frequency estimate and additional phase
|
|
* adjustment due to frequency error for the next
|
|
* second. When the PPS signal is engaged, gnaw on the
|
|
* watchdog counter and update the frequency computed by
|
|
* the pll and the PPS signal.
|
|
*/
|
|
#ifdef PPS_SYNC
|
|
pps_valid++;
|
|
if (pps_valid == PPS_VALID) {
|
|
pps_jitter = MAXTIME;
|
|
pps_stabil = MAXFREQ;
|
|
time_status &= ~(STA_PPSSIGNAL | STA_PPSJITTER |
|
|
STA_PPSWANDER | STA_PPSERROR);
|
|
}
|
|
ltemp = time_freq + pps_freq;
|
|
#else
|
|
ltemp = time_freq;
|
|
#endif /* PPS_SYNC */
|
|
if (ltemp < 0)
|
|
time_adj -= -ltemp >>
|
|
(SHIFT_USEC + SHIFT_HZ - SHIFT_SCALE);
|
|
else
|
|
time_adj += ltemp >>
|
|
(SHIFT_USEC + SHIFT_HZ - SHIFT_SCALE);
|
|
|
|
#if SHIFT_HZ == 7
|
|
/*
|
|
* When the CPU clock oscillator frequency is not a
|
|
* power of two in Hz, the SHIFT_HZ is only an
|
|
* approximate scale factor. In the SunOS kernel, this
|
|
* results in a PLL gain factor of 1/1.28 = 0.78 what it
|
|
* should be. In the following code the overall gain is
|
|
* increased by a factor of 1.25, which results in a
|
|
* residual error less than 3 percent.
|
|
*/
|
|
/* Same thing applies for FreeBSD --GAW */
|
|
if (hz == 100) {
|
|
if (time_adj < 0)
|
|
time_adj -= -time_adj >> 2;
|
|
else
|
|
time_adj += time_adj >> 2;
|
|
}
|
|
#endif /* SHIFT_HZ */
|
|
|
|
/* XXX - this is really bogus, but can't be fixed until
|
|
xntpd's idea of the system clock is fixed to know how
|
|
the user wants leap seconds handled; in the mean time,
|
|
we assume that users of NTP are running without proper
|
|
leap second support (this is now the default anyway) */
|
|
/*
|
|
* Leap second processing. If in leap-insert state at
|
|
* the end of the day, the system clock is set back one
|
|
* second; if in leap-delete state, the system clock is
|
|
* set ahead one second. The microtime() routine or
|
|
* external clock driver will insure that reported time
|
|
* is always monotonic. The ugly divides should be
|
|
* replaced.
|
|
*/
|
|
switch (time_state) {
|
|
|
|
case TIME_OK:
|
|
if (time_status & STA_INS)
|
|
time_state = TIME_INS;
|
|
else if (time_status & STA_DEL)
|
|
time_state = TIME_DEL;
|
|
break;
|
|
|
|
case TIME_INS:
|
|
if (newtime.tv_sec % 86400 == 0) {
|
|
newtime.tv_sec--;
|
|
time_state = TIME_OOP;
|
|
}
|
|
break;
|
|
|
|
case TIME_DEL:
|
|
if ((newtime.tv_sec + 1) % 86400 == 0) {
|
|
newtime.tv_sec++;
|
|
time_state = TIME_WAIT;
|
|
}
|
|
break;
|
|
|
|
case TIME_OOP:
|
|
time_state = TIME_WAIT;
|
|
break;
|
|
|
|
case TIME_WAIT:
|
|
if (!(time_status & (STA_INS | STA_DEL)))
|
|
time_state = TIME_OK;
|
|
}
|
|
}
|
|
CPU_CLOCKUPDATE(&time, &newtime);
|
|
}
|
|
|
|
/*
|
|
* Process callouts at a very low cpu priority, so we don't keep the
|
|
* relatively high clock interrupt priority any longer than necessary.
|
|
*/
|
|
if (TAILQ_FIRST(&callwheel[ticks & callwheelmask]) != NULL) {
|
|
if (CLKF_BASEPRI(frame)) {
|
|
/*
|
|
* Save the overhead of a software interrupt;
|
|
* it will happen as soon as we return, so do it now.
|
|
*/
|
|
(void)splsoftclock();
|
|
softclock();
|
|
} else
|
|
setsoftclock();
|
|
} else if (softticks + 1 == ticks) {
|
|
++softticks;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* The callout mechanism is based on the work of Adam M. Costello and
|
|
* George Varghese, published in a technical report entitled "Redesigning
|
|
* the BSD Callout and Timer Facilities" and modified slightly for inclusion
|
|
* in FreeBSD by Justin T. Gibbs. The original work on the data structures
|
|
* used in this implementation was published by G.Varghese and A. Lauck in
|
|
* the paper "Hashed and Hierarchical Timing Wheels: Data Structures for
|
|
* the Efficient Implementation of a Timer Facility" in the Proceedings of
|
|
* the 11th ACM Annual Symposium on Operating Systems Principles,
|
|
* Austin, Texas Nov 1987.
|
|
*/
|
|
/*
|
|
* Software (low priority) clock interrupt.
|
|
* Run periodic events from timeout queue.
|
|
*/
|
|
/*ARGSUSED*/
|
|
void
|
|
softclock()
|
|
{
|
|
register struct callout *c;
|
|
register struct callout_tailq *bucket;
|
|
register int s;
|
|
register int curticks;
|
|
register int steps; /*
|
|
* Number of steps taken since
|
|
* we last allowed interrupts.
|
|
*/
|
|
|
|
#ifndef MAX_SOFTCLOCK_STEPS
|
|
#define MAX_SOFTCLOCK_STEPS 100 /* Maximum allowed value of steps. */
|
|
#endif /* MAX_SOFTCLOCK_STEPS */
|
|
|
|
steps = 0;
|
|
s = splhigh();
|
|
while (softticks != ticks) {
|
|
softticks++;
|
|
/*
|
|
* softticks may be modified by hard clock, so cache
|
|
* it while we work on a given bucket.
|
|
*/
|
|
curticks = softticks;
|
|
bucket = &callwheel[curticks & callwheelmask];
|
|
c = TAILQ_FIRST(bucket);
|
|
while (c) {
|
|
if (c->c_time != curticks) {
|
|
c = TAILQ_NEXT(c, c_links.tqe);
|
|
++steps;
|
|
if (steps >= MAX_SOFTCLOCK_STEPS) {
|
|
nextsoftcheck = c;
|
|
/* Give interrupts a chance. */
|
|
splx(s);
|
|
s = splhigh();
|
|
c = nextsoftcheck;
|
|
steps = 0;
|
|
}
|
|
} else {
|
|
void (*c_func)(void *);
|
|
void *c_arg;
|
|
|
|
nextsoftcheck = TAILQ_NEXT(c, c_links.tqe);
|
|
TAILQ_REMOVE(bucket, c, c_links.tqe);
|
|
c_func = c->c_func;
|
|
c_arg = c->c_arg;
|
|
c->c_func = NULL;
|
|
SLIST_INSERT_HEAD(&callfree, c, c_links.sle);
|
|
splx(s);
|
|
c_func(c_arg);
|
|
s = splhigh();
|
|
steps = 0;
|
|
c = nextsoftcheck;
|
|
}
|
|
}
|
|
}
|
|
nextsoftcheck = NULL;
|
|
splx(s);
|
|
}
|
|
|
|
/*
|
|
* timeout --
|
|
* Execute a function after a specified length of time.
|
|
*
|
|
* untimeout --
|
|
* Cancel previous timeout function call.
|
|
*
|
|
* callout_handle_init --
|
|
* Initialize a handle so that using it with untimeout is benign.
|
|
*
|
|
* See AT&T BCI Driver Reference Manual for specification. This
|
|
* implementation differs from that one in that although an
|
|
* identification value is returned from timeout, the original
|
|
* arguments to timeout as well as the identifier are used to
|
|
* identify entries for untimeout.
|
|
*/
|
|
struct callout_handle
|
|
timeout(ftn, arg, to_ticks)
|
|
timeout_t ftn;
|
|
void *arg;
|
|
register int to_ticks;
|
|
{
|
|
int s;
|
|
struct callout *new;
|
|
struct callout_handle handle;
|
|
|
|
if (to_ticks <= 0)
|
|
to_ticks = 1;
|
|
|
|
/* Lock out the clock. */
|
|
s = splhigh();
|
|
|
|
/* Fill in the next free callout structure. */
|
|
new = SLIST_FIRST(&callfree);
|
|
if (new == NULL)
|
|
/* XXX Attempt to malloc first */
|
|
panic("timeout table full");
|
|
|
|
SLIST_REMOVE_HEAD(&callfree, c_links.sle);
|
|
new->c_arg = arg;
|
|
new->c_func = ftn;
|
|
new->c_time = ticks + to_ticks;
|
|
TAILQ_INSERT_TAIL(&callwheel[new->c_time & callwheelmask],
|
|
new, c_links.tqe);
|
|
|
|
splx(s);
|
|
handle.callout = new;
|
|
return (handle);
|
|
}
|
|
|
|
void
|
|
untimeout(ftn, arg, handle)
|
|
timeout_t ftn;
|
|
void *arg;
|
|
struct callout_handle handle;
|
|
{
|
|
register int s;
|
|
|
|
/*
|
|
* Check for a handle that was initialized
|
|
* by callout_handle_init, but never used
|
|
* for a real timeout.
|
|
*/
|
|
if (handle.callout == NULL)
|
|
return;
|
|
|
|
s = splhigh();
|
|
if ((handle.callout->c_func == ftn)
|
|
&& (handle.callout->c_arg == arg)) {
|
|
if (nextsoftcheck == handle.callout) {
|
|
nextsoftcheck = TAILQ_NEXT(handle.callout, c_links.tqe);
|
|
}
|
|
TAILQ_REMOVE(&callwheel[handle.callout->c_time & callwheelmask],
|
|
handle.callout, c_links.tqe);
|
|
handle.callout->c_func = NULL;
|
|
SLIST_INSERT_HEAD(&callfree, handle.callout, c_links.sle);
|
|
}
|
|
splx(s);
|
|
}
|
|
|
|
void
|
|
callout_handle_init(struct callout_handle *handle)
|
|
{
|
|
handle->callout = NULL;
|
|
}
|
|
|
|
void
|
|
gettime(struct timeval *tvp)
|
|
{
|
|
int s;
|
|
|
|
s = splclock();
|
|
/* XXX should use microtime() iff tv_usec is used. */
|
|
*tvp = time;
|
|
splx(s);
|
|
}
|
|
|
|
/*
|
|
* Compute number of hz until specified time. Used to
|
|
* compute third argument to timeout() from an absolute time.
|
|
*/
|
|
int
|
|
hzto(tv)
|
|
struct timeval *tv;
|
|
{
|
|
register unsigned long ticks;
|
|
register long sec, usec;
|
|
int s;
|
|
|
|
/*
|
|
* If the number of usecs in the whole seconds part of the time
|
|
* difference fits in a long, then the total number of usecs will
|
|
* fit in an unsigned long. Compute the total and convert it to
|
|
* ticks, rounding up and adding 1 to allow for the current tick
|
|
* to expire. Rounding also depends on unsigned long arithmetic
|
|
* to avoid overflow.
|
|
*
|
|
* Otherwise, if the number of ticks in the whole seconds part of
|
|
* the time difference fits in a long, then convert the parts to
|
|
* ticks separately and add, using similar rounding methods and
|
|
* overflow avoidance. This method would work in the previous
|
|
* case but it is slightly slower and assumes that hz is integral.
|
|
*
|
|
* Otherwise, round the time difference down to the maximum
|
|
* representable value.
|
|
*
|
|
* If ints have 32 bits, then the maximum value for any timeout in
|
|
* 10ms ticks is 248 days.
|
|
*/
|
|
s = splclock();
|
|
sec = tv->tv_sec - time.tv_sec;
|
|
usec = tv->tv_usec - time.tv_usec;
|
|
splx(s);
|
|
if (usec < 0) {
|
|
sec--;
|
|
usec += 1000000;
|
|
}
|
|
if (sec < 0) {
|
|
#ifdef DIAGNOSTIC
|
|
printf("hzto: negative time difference %ld sec %ld usec\n",
|
|
sec, usec);
|
|
#endif
|
|
ticks = 1;
|
|
} else if (sec <= LONG_MAX / 1000000)
|
|
ticks = (sec * 1000000 + (unsigned long)usec + (tick - 1))
|
|
/ tick + 1;
|
|
else if (sec <= LONG_MAX / hz)
|
|
ticks = sec * hz
|
|
+ ((unsigned long)usec + (tick - 1)) / tick + 1;
|
|
else
|
|
ticks = LONG_MAX;
|
|
if (ticks > INT_MAX)
|
|
ticks = INT_MAX;
|
|
return (ticks);
|
|
}
|
|
|
|
/*
|
|
* Start profiling on a process.
|
|
*
|
|
* Kernel profiling passes proc0 which never exits and hence
|
|
* keeps the profile clock running constantly.
|
|
*/
|
|
void
|
|
startprofclock(p)
|
|
register struct proc *p;
|
|
{
|
|
int s;
|
|
|
|
if ((p->p_flag & P_PROFIL) == 0) {
|
|
p->p_flag |= P_PROFIL;
|
|
if (++profprocs == 1 && stathz != 0) {
|
|
s = splstatclock();
|
|
psdiv = pscnt = psratio;
|
|
setstatclockrate(profhz);
|
|
splx(s);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Stop profiling on a process.
|
|
*/
|
|
void
|
|
stopprofclock(p)
|
|
register struct proc *p;
|
|
{
|
|
int s;
|
|
|
|
if (p->p_flag & P_PROFIL) {
|
|
p->p_flag &= ~P_PROFIL;
|
|
if (--profprocs == 0 && stathz != 0) {
|
|
s = splstatclock();
|
|
psdiv = pscnt = 1;
|
|
setstatclockrate(stathz);
|
|
splx(s);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Statistics clock. Grab profile sample, and if divider reaches 0,
|
|
* do process and kernel statistics.
|
|
*/
|
|
void
|
|
statclock(frame)
|
|
register struct clockframe *frame;
|
|
{
|
|
#ifdef GPROF
|
|
register struct gmonparam *g;
|
|
#endif
|
|
register struct proc *p;
|
|
register int i;
|
|
struct pstats *pstats;
|
|
long rss;
|
|
struct rusage *ru;
|
|
struct vmspace *vm;
|
|
|
|
if (CLKF_USERMODE(frame)) {
|
|
p = curproc;
|
|
if (p->p_flag & P_PROFIL)
|
|
addupc_intr(p, CLKF_PC(frame), 1);
|
|
if (--pscnt > 0)
|
|
return;
|
|
/*
|
|
* Came from user mode; CPU was in user state.
|
|
* If this process is being profiled record the tick.
|
|
*/
|
|
p->p_uticks++;
|
|
if (p->p_nice > NZERO)
|
|
cp_time[CP_NICE]++;
|
|
else
|
|
cp_time[CP_USER]++;
|
|
} else {
|
|
#ifdef GPROF
|
|
/*
|
|
* Kernel statistics are just like addupc_intr, only easier.
|
|
*/
|
|
g = &_gmonparam;
|
|
if (g->state == GMON_PROF_ON) {
|
|
i = CLKF_PC(frame) - g->lowpc;
|
|
if (i < g->textsize) {
|
|
i /= HISTFRACTION * sizeof(*g->kcount);
|
|
g->kcount[i]++;
|
|
}
|
|
}
|
|
#endif
|
|
if (--pscnt > 0)
|
|
return;
|
|
/*
|
|
* Came from kernel mode, so we were:
|
|
* - handling an interrupt,
|
|
* - doing syscall or trap work on behalf of the current
|
|
* user process, or
|
|
* - spinning in the idle loop.
|
|
* Whichever it is, charge the time as appropriate.
|
|
* Note that we charge interrupts to the current process,
|
|
* regardless of whether they are ``for'' that process,
|
|
* so that we know how much of its real time was spent
|
|
* in ``non-process'' (i.e., interrupt) work.
|
|
*/
|
|
p = curproc;
|
|
if (CLKF_INTR(frame)) {
|
|
if (p != NULL)
|
|
p->p_iticks++;
|
|
cp_time[CP_INTR]++;
|
|
} else if (p != NULL && !(p->p_flag & P_IDLEPROC)) {
|
|
p->p_sticks++;
|
|
cp_time[CP_SYS]++;
|
|
} else
|
|
cp_time[CP_IDLE]++;
|
|
}
|
|
pscnt = psdiv;
|
|
|
|
/*
|
|
* We maintain statistics shown by user-level statistics
|
|
* programs: the amount of time in each cpu state, and
|
|
* the amount of time each of DK_NDRIVE ``drives'' is busy.
|
|
*
|
|
* XXX should either run linked list of drives, or (better)
|
|
* grab timestamps in the start & done code.
|
|
*/
|
|
for (i = 0; i < DK_NDRIVE; i++)
|
|
if (dk_busy & (1 << i))
|
|
dk_time[i]++;
|
|
|
|
/*
|
|
* We adjust the priority of the current process. The priority of
|
|
* a process gets worse as it accumulates CPU time. The cpu usage
|
|
* estimator (p_estcpu) is increased here. The formula for computing
|
|
* priorities (in kern_synch.c) will compute a different value each
|
|
* time p_estcpu increases by 4. The cpu usage estimator ramps up
|
|
* quite quickly when the process is running (linearly), and decays
|
|
* away exponentially, at a rate which is proportionally slower when
|
|
* the system is busy. The basic principal is that the system will
|
|
* 90% forget that the process used a lot of CPU time in 5 * loadav
|
|
* seconds. This causes the system to favor processes which haven't
|
|
* run much recently, and to round-robin among other processes.
|
|
*/
|
|
if (p != NULL) {
|
|
p->p_cpticks++;
|
|
if (++p->p_estcpu == 0)
|
|
p->p_estcpu--;
|
|
if ((p->p_estcpu & 3) == 0) {
|
|
resetpriority(p);
|
|
if (p->p_priority >= PUSER)
|
|
p->p_priority = p->p_usrpri;
|
|
}
|
|
|
|
/* Update resource usage integrals and maximums. */
|
|
if ((pstats = p->p_stats) != NULL &&
|
|
(ru = &pstats->p_ru) != NULL &&
|
|
(vm = p->p_vmspace) != NULL) {
|
|
ru->ru_ixrss += vm->vm_tsize * PAGE_SIZE / 1024;
|
|
ru->ru_idrss += vm->vm_dsize * PAGE_SIZE / 1024;
|
|
ru->ru_isrss += vm->vm_ssize * PAGE_SIZE / 1024;
|
|
rss = vm->vm_pmap.pm_stats.resident_count *
|
|
PAGE_SIZE / 1024;
|
|
if (ru->ru_maxrss < rss)
|
|
ru->ru_maxrss = rss;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Return information about system clocks.
|
|
*/
|
|
static int
|
|
sysctl_kern_clockrate SYSCTL_HANDLER_ARGS
|
|
{
|
|
struct clockinfo clkinfo;
|
|
/*
|
|
* Construct clockinfo structure.
|
|
*/
|
|
clkinfo.hz = hz;
|
|
clkinfo.tick = tick;
|
|
clkinfo.tickadj = tickadj;
|
|
clkinfo.profhz = profhz;
|
|
clkinfo.stathz = stathz ? stathz : hz;
|
|
return (sysctl_handle_opaque(oidp, &clkinfo, sizeof clkinfo, req));
|
|
}
|
|
|
|
SYSCTL_PROC(_kern, KERN_CLOCKRATE, clockrate, CTLTYPE_STRUCT|CTLFLAG_RD,
|
|
0, 0, sysctl_kern_clockrate, "S,clockinfo","");
|
|
|
|
#ifdef PPS_SYNC
|
|
/*
|
|
* hardpps() - discipline CPU clock oscillator to external PPS signal
|
|
*
|
|
* This routine is called at each PPS interrupt in order to discipline
|
|
* the CPU clock oscillator to the PPS signal. It measures the PPS phase
|
|
* and leaves it in a handy spot for the hardclock() routine. It
|
|
* integrates successive PPS phase differences and calculates the
|
|
* frequency offset. This is used in hardclock() to discipline the CPU
|
|
* clock oscillator so that intrinsic frequency error is cancelled out.
|
|
* The code requires the caller to capture the time and hardware counter
|
|
* value at the on-time PPS signal transition.
|
|
*
|
|
* Note that, on some Unix systems, this routine runs at an interrupt
|
|
* priority level higher than the timer interrupt routine hardclock().
|
|
* Therefore, the variables used are distinct from the hardclock()
|
|
* variables, except for certain exceptions: The PPS frequency pps_freq
|
|
* and phase pps_offset variables are determined by this routine and
|
|
* updated atomically. The time_tolerance variable can be considered a
|
|
* constant, since it is infrequently changed, and then only when the
|
|
* PPS signal is disabled. The watchdog counter pps_valid is updated
|
|
* once per second by hardclock() and is atomically cleared in this
|
|
* routine.
|
|
*/
|
|
void
|
|
hardpps(tvp, usec)
|
|
struct timeval *tvp; /* time at PPS */
|
|
long usec; /* hardware counter at PPS */
|
|
{
|
|
long u_usec, v_usec, bigtick;
|
|
long cal_sec, cal_usec;
|
|
|
|
/*
|
|
* An occasional glitch can be produced when the PPS interrupt
|
|
* occurs in the hardclock() routine before the time variable is
|
|
* updated. Here the offset is discarded when the difference
|
|
* between it and the last one is greater than tick/2, but not
|
|
* if the interval since the first discard exceeds 30 s.
|
|
*/
|
|
time_status |= STA_PPSSIGNAL;
|
|
time_status &= ~(STA_PPSJITTER | STA_PPSWANDER | STA_PPSERROR);
|
|
pps_valid = 0;
|
|
u_usec = -tvp->tv_usec;
|
|
if (u_usec < -500000)
|
|
u_usec += 1000000;
|
|
v_usec = pps_offset - u_usec;
|
|
if (v_usec < 0)
|
|
v_usec = -v_usec;
|
|
if (v_usec > (tick >> 1)) {
|
|
if (pps_glitch > MAXGLITCH) {
|
|
pps_glitch = 0;
|
|
pps_tf[2] = u_usec;
|
|
pps_tf[1] = u_usec;
|
|
} else {
|
|
pps_glitch++;
|
|
u_usec = pps_offset;
|
|
}
|
|
} else
|
|
pps_glitch = 0;
|
|
|
|
/*
|
|
* A three-stage median filter is used to help deglitch the pps
|
|
* time. The median sample becomes the time offset estimate; the
|
|
* difference between the other two samples becomes the time
|
|
* dispersion (jitter) estimate.
|
|
*/
|
|
pps_tf[2] = pps_tf[1];
|
|
pps_tf[1] = pps_tf[0];
|
|
pps_tf[0] = u_usec;
|
|
if (pps_tf[0] > pps_tf[1]) {
|
|
if (pps_tf[1] > pps_tf[2]) {
|
|
pps_offset = pps_tf[1]; /* 0 1 2 */
|
|
v_usec = pps_tf[0] - pps_tf[2];
|
|
} else if (pps_tf[2] > pps_tf[0]) {
|
|
pps_offset = pps_tf[0]; /* 2 0 1 */
|
|
v_usec = pps_tf[2] - pps_tf[1];
|
|
} else {
|
|
pps_offset = pps_tf[2]; /* 0 2 1 */
|
|
v_usec = pps_tf[0] - pps_tf[1];
|
|
}
|
|
} else {
|
|
if (pps_tf[1] < pps_tf[2]) {
|
|
pps_offset = pps_tf[1]; /* 2 1 0 */
|
|
v_usec = pps_tf[2] - pps_tf[0];
|
|
} else if (pps_tf[2] < pps_tf[0]) {
|
|
pps_offset = pps_tf[0]; /* 1 0 2 */
|
|
v_usec = pps_tf[1] - pps_tf[2];
|
|
} else {
|
|
pps_offset = pps_tf[2]; /* 1 2 0 */
|
|
v_usec = pps_tf[1] - pps_tf[0];
|
|
}
|
|
}
|
|
if (v_usec > MAXTIME)
|
|
pps_jitcnt++;
|
|
v_usec = (v_usec << PPS_AVG) - pps_jitter;
|
|
if (v_usec < 0)
|
|
pps_jitter -= -v_usec >> PPS_AVG;
|
|
else
|
|
pps_jitter += v_usec >> PPS_AVG;
|
|
if (pps_jitter > (MAXTIME >> 1))
|
|
time_status |= STA_PPSJITTER;
|
|
|
|
/*
|
|
* During the calibration interval adjust the starting time when
|
|
* the tick overflows. At the end of the interval compute the
|
|
* duration of the interval and the difference of the hardware
|
|
* counters at the beginning and end of the interval. This code
|
|
* is deliciously complicated by the fact valid differences may
|
|
* exceed the value of tick when using long calibration
|
|
* intervals and small ticks. Note that the counter can be
|
|
* greater than tick if caught at just the wrong instant, but
|
|
* the values returned and used here are correct.
|
|
*/
|
|
bigtick = (long)tick << SHIFT_USEC;
|
|
pps_usec -= pps_freq;
|
|
if (pps_usec >= bigtick)
|
|
pps_usec -= bigtick;
|
|
if (pps_usec < 0)
|
|
pps_usec += bigtick;
|
|
pps_time.tv_sec++;
|
|
pps_count++;
|
|
if (pps_count < (1 << pps_shift))
|
|
return;
|
|
pps_count = 0;
|
|
pps_calcnt++;
|
|
u_usec = usec << SHIFT_USEC;
|
|
v_usec = pps_usec - u_usec;
|
|
if (v_usec >= bigtick >> 1)
|
|
v_usec -= bigtick;
|
|
if (v_usec < -(bigtick >> 1))
|
|
v_usec += bigtick;
|
|
if (v_usec < 0)
|
|
v_usec = -(-v_usec >> pps_shift);
|
|
else
|
|
v_usec = v_usec >> pps_shift;
|
|
pps_usec = u_usec;
|
|
cal_sec = tvp->tv_sec;
|
|
cal_usec = tvp->tv_usec;
|
|
cal_sec -= pps_time.tv_sec;
|
|
cal_usec -= pps_time.tv_usec;
|
|
if (cal_usec < 0) {
|
|
cal_usec += 1000000;
|
|
cal_sec--;
|
|
}
|
|
pps_time = *tvp;
|
|
|
|
/*
|
|
* Check for lost interrupts, noise, excessive jitter and
|
|
* excessive frequency error. The number of timer ticks during
|
|
* the interval may vary +-1 tick. Add to this a margin of one
|
|
* tick for the PPS signal jitter and maximum frequency
|
|
* deviation. If the limits are exceeded, the calibration
|
|
* interval is reset to the minimum and we start over.
|
|
*/
|
|
u_usec = (long)tick << 1;
|
|
if (!((cal_sec == -1 && cal_usec > (1000000 - u_usec))
|
|
|| (cal_sec == 0 && cal_usec < u_usec))
|
|
|| v_usec > time_tolerance || v_usec < -time_tolerance) {
|
|
pps_errcnt++;
|
|
pps_shift = PPS_SHIFT;
|
|
pps_intcnt = 0;
|
|
time_status |= STA_PPSERROR;
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* A three-stage median filter is used to help deglitch the pps
|
|
* frequency. The median sample becomes the frequency offset
|
|
* estimate; the difference between the other two samples
|
|
* becomes the frequency dispersion (stability) estimate.
|
|
*/
|
|
pps_ff[2] = pps_ff[1];
|
|
pps_ff[1] = pps_ff[0];
|
|
pps_ff[0] = v_usec;
|
|
if (pps_ff[0] > pps_ff[1]) {
|
|
if (pps_ff[1] > pps_ff[2]) {
|
|
u_usec = pps_ff[1]; /* 0 1 2 */
|
|
v_usec = pps_ff[0] - pps_ff[2];
|
|
} else if (pps_ff[2] > pps_ff[0]) {
|
|
u_usec = pps_ff[0]; /* 2 0 1 */
|
|
v_usec = pps_ff[2] - pps_ff[1];
|
|
} else {
|
|
u_usec = pps_ff[2]; /* 0 2 1 */
|
|
v_usec = pps_ff[0] - pps_ff[1];
|
|
}
|
|
} else {
|
|
if (pps_ff[1] < pps_ff[2]) {
|
|
u_usec = pps_ff[1]; /* 2 1 0 */
|
|
v_usec = pps_ff[2] - pps_ff[0];
|
|
} else if (pps_ff[2] < pps_ff[0]) {
|
|
u_usec = pps_ff[0]; /* 1 0 2 */
|
|
v_usec = pps_ff[1] - pps_ff[2];
|
|
} else {
|
|
u_usec = pps_ff[2]; /* 1 2 0 */
|
|
v_usec = pps_ff[1] - pps_ff[0];
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Here the frequency dispersion (stability) is updated. If it
|
|
* is less than one-fourth the maximum (MAXFREQ), the frequency
|
|
* offset is updated as well, but clamped to the tolerance. It
|
|
* will be processed later by the hardclock() routine.
|
|
*/
|
|
v_usec = (v_usec >> 1) - pps_stabil;
|
|
if (v_usec < 0)
|
|
pps_stabil -= -v_usec >> PPS_AVG;
|
|
else
|
|
pps_stabil += v_usec >> PPS_AVG;
|
|
if (pps_stabil > MAXFREQ >> 2) {
|
|
pps_stbcnt++;
|
|
time_status |= STA_PPSWANDER;
|
|
return;
|
|
}
|
|
if (time_status & STA_PPSFREQ) {
|
|
if (u_usec < 0) {
|
|
pps_freq -= -u_usec >> PPS_AVG;
|
|
if (pps_freq < -time_tolerance)
|
|
pps_freq = -time_tolerance;
|
|
u_usec = -u_usec;
|
|
} else {
|
|
pps_freq += u_usec >> PPS_AVG;
|
|
if (pps_freq > time_tolerance)
|
|
pps_freq = time_tolerance;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Here the calibration interval is adjusted. If the maximum
|
|
* time difference is greater than tick / 4, reduce the interval
|
|
* by half. If this is not the case for four consecutive
|
|
* intervals, double the interval.
|
|
*/
|
|
if (u_usec << pps_shift > bigtick >> 2) {
|
|
pps_intcnt = 0;
|
|
if (pps_shift > PPS_SHIFT)
|
|
pps_shift--;
|
|
} else if (pps_intcnt >= 4) {
|
|
pps_intcnt = 0;
|
|
if (pps_shift < PPS_SHIFTMAX)
|
|
pps_shift++;
|
|
} else
|
|
pps_intcnt++;
|
|
}
|
|
#endif /* PPS_SYNC */
|