0c14ff0eb5
system calls now enter without Giant held, and then in some cases, acquire Giant explicitly. Remove a number of other MPSAFE annotations in the credential code and tweak one or two other adjacent comments.
589 lines
17 KiB
C
589 lines
17 KiB
C
/*-
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* Copyright (c) 1982, 1986, 1993
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* The Regents of the University of California. All rights reserved.
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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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* 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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* @(#)subr_prof.c 8.3 (Berkeley) 9/23/93
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/sysproto.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/resourcevar.h>
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#include <sys/sysctl.h>
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#include <machine/cpu.h>
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#ifdef GPROF
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#include <sys/malloc.h>
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#include <sys/gmon.h>
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#undef MCOUNT
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static MALLOC_DEFINE(M_GPROF, "gprof", "kernel profiling buffer");
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static void kmstartup(void *);
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SYSINIT(kmem, SI_SUB_KPROF, SI_ORDER_FIRST, kmstartup, NULL)
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struct gmonparam _gmonparam = { GMON_PROF_OFF };
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#ifdef GUPROF
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void
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nullfunc_loop_profiled()
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{
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int i;
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for (i = 0; i < CALIB_SCALE; i++)
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nullfunc_profiled();
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}
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#define nullfunc_loop_profiled_end nullfunc_profiled /* XXX */
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void
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nullfunc_profiled()
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{
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}
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#endif /* GUPROF */
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/*
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* Update the histograms to support extending the text region arbitrarily.
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* This is done slightly naively (no sparse regions), so will waste slight
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* amounts of memory, but will overall work nicely enough to allow profiling
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* of KLDs.
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*/
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void
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kmupetext(uintfptr_t nhighpc)
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{
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struct gmonparam np; /* slightly large */
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struct gmonparam *p = &_gmonparam;
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char *cp;
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GIANT_REQUIRED;
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bcopy(p, &np, sizeof(*p));
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np.highpc = ROUNDUP(nhighpc, HISTFRACTION * sizeof(HISTCOUNTER));
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if (np.highpc <= p->highpc)
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return;
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np.textsize = np.highpc - p->lowpc;
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np.kcountsize = np.textsize / HISTFRACTION;
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np.hashfraction = HASHFRACTION;
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np.fromssize = np.textsize / HASHFRACTION;
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np.tolimit = np.textsize * ARCDENSITY / 100;
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if (np.tolimit < MINARCS)
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np.tolimit = MINARCS;
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else if (np.tolimit > MAXARCS)
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np.tolimit = MAXARCS;
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np.tossize = np.tolimit * sizeof(struct tostruct);
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cp = malloc(np.kcountsize + np.fromssize + np.tossize,
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M_GPROF, M_WAITOK);
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/*
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* Check for something else extending highpc while we slept.
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*/
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if (np.highpc <= p->highpc) {
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free(cp, M_GPROF);
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return;
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}
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np.tos = (struct tostruct *)cp;
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cp += np.tossize;
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np.kcount = (HISTCOUNTER *)cp;
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cp += np.kcountsize;
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np.froms = (u_short *)cp;
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#ifdef GUPROF
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/* Reinitialize pointers to overhead counters. */
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np.cputime_count = &KCOUNT(&np, PC_TO_I(&np, cputime));
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np.mcount_count = &KCOUNT(&np, PC_TO_I(&np, mcount));
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np.mexitcount_count = &KCOUNT(&np, PC_TO_I(&np, mexitcount));
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#endif
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critical_enter();
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bcopy(p->tos, np.tos, p->tossize);
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bzero((char *)np.tos + p->tossize, np.tossize - p->tossize);
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bcopy(p->kcount, np.kcount, p->kcountsize);
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bzero((char *)np.kcount + p->kcountsize, np.kcountsize -
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p->kcountsize);
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bcopy(p->froms, np.froms, p->fromssize);
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bzero((char *)np.froms + p->fromssize, np.fromssize - p->fromssize);
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cp = (char *)p->tos;
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bcopy(&np, p, sizeof(*p));
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critical_exit();
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free(cp, M_GPROF);
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}
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static void
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kmstartup(dummy)
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void *dummy;
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{
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char *cp;
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struct gmonparam *p = &_gmonparam;
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#ifdef GUPROF
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int cputime_overhead;
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int empty_loop_time;
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int i;
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int mcount_overhead;
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int mexitcount_overhead;
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int nullfunc_loop_overhead;
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int nullfunc_loop_profiled_time;
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uintfptr_t tmp_addr;
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#endif
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/*
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* Round lowpc and highpc to multiples of the density we're using
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* so the rest of the scaling (here and in gprof) stays in ints.
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*/
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p->lowpc = ROUNDDOWN((u_long)btext, HISTFRACTION * sizeof(HISTCOUNTER));
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p->highpc = ROUNDUP((u_long)etext, HISTFRACTION * sizeof(HISTCOUNTER));
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p->textsize = p->highpc - p->lowpc;
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printf("Profiling kernel, textsize=%lu [%jx..%jx]\n",
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p->textsize, (uintmax_t)p->lowpc, (uintmax_t)p->highpc);
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p->kcountsize = p->textsize / HISTFRACTION;
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p->hashfraction = HASHFRACTION;
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p->fromssize = p->textsize / HASHFRACTION;
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p->tolimit = p->textsize * ARCDENSITY / 100;
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if (p->tolimit < MINARCS)
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p->tolimit = MINARCS;
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else if (p->tolimit > MAXARCS)
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p->tolimit = MAXARCS;
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p->tossize = p->tolimit * sizeof(struct tostruct);
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cp = (char *)malloc(p->kcountsize + p->fromssize + p->tossize,
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M_GPROF, M_WAITOK | M_ZERO);
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p->tos = (struct tostruct *)cp;
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cp += p->tossize;
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p->kcount = (HISTCOUNTER *)cp;
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cp += p->kcountsize;
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p->froms = (u_short *)cp;
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p->histcounter_type = FUNCTION_ALIGNMENT / HISTFRACTION * NBBY;
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#ifdef GUPROF
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/* Signed counters. */
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p->histcounter_type = -p->histcounter_type;
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/* Initialize pointers to overhead counters. */
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p->cputime_count = &KCOUNT(p, PC_TO_I(p, cputime));
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p->mcount_count = &KCOUNT(p, PC_TO_I(p, mcount));
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p->mexitcount_count = &KCOUNT(p, PC_TO_I(p, mexitcount));
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/*
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* Disable interrupts to avoid interference while we calibrate
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* things.
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*/
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critical_enter();
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/*
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* Determine overheads.
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* XXX this needs to be repeated for each useful timer/counter.
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*/
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cputime_overhead = 0;
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startguprof(p);
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for (i = 0; i < CALIB_SCALE; i++)
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cputime_overhead += cputime();
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empty_loop();
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startguprof(p);
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empty_loop();
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empty_loop_time = cputime();
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nullfunc_loop_profiled();
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/*
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* Start profiling. There won't be any normal function calls since
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* interrupts are disabled, but we will call the profiling routines
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* directly to determine their overheads.
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*/
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p->state = GMON_PROF_HIRES;
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startguprof(p);
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nullfunc_loop_profiled();
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startguprof(p);
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for (i = 0; i < CALIB_SCALE; i++)
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MCOUNT_OVERHEAD(profil);
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mcount_overhead = KCOUNT(p, PC_TO_I(p, profil));
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startguprof(p);
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for (i = 0; i < CALIB_SCALE; i++)
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MEXITCOUNT_OVERHEAD();
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MEXITCOUNT_OVERHEAD_GETLABEL(tmp_addr);
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mexitcount_overhead = KCOUNT(p, PC_TO_I(p, tmp_addr));
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p->state = GMON_PROF_OFF;
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stopguprof(p);
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critical_exit();
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nullfunc_loop_profiled_time = 0;
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for (tmp_addr = (uintfptr_t)nullfunc_loop_profiled;
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tmp_addr < (uintfptr_t)nullfunc_loop_profiled_end;
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tmp_addr += HISTFRACTION * sizeof(HISTCOUNTER))
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nullfunc_loop_profiled_time += KCOUNT(p, PC_TO_I(p, tmp_addr));
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#define CALIB_DOSCALE(count) (((count) + CALIB_SCALE / 3) / CALIB_SCALE)
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#define c2n(count, freq) ((int)((count) * 1000000000LL / freq))
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printf("cputime %d, empty_loop %d, nullfunc_loop_profiled %d, mcount %d, mexitcount %d\n",
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CALIB_DOSCALE(c2n(cputime_overhead, p->profrate)),
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CALIB_DOSCALE(c2n(empty_loop_time, p->profrate)),
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CALIB_DOSCALE(c2n(nullfunc_loop_profiled_time, p->profrate)),
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CALIB_DOSCALE(c2n(mcount_overhead, p->profrate)),
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CALIB_DOSCALE(c2n(mexitcount_overhead, p->profrate)));
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cputime_overhead -= empty_loop_time;
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mcount_overhead -= empty_loop_time;
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mexitcount_overhead -= empty_loop_time;
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/*-
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* Profiling overheads are determined by the times between the
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* following events:
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* MC1: mcount() is called
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* MC2: cputime() (called from mcount()) latches the timer
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* MC3: mcount() completes
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* ME1: mexitcount() is called
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* ME2: cputime() (called from mexitcount()) latches the timer
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* ME3: mexitcount() completes.
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* The times between the events vary slightly depending on instruction
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* combination and cache misses, etc. Attempt to determine the
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* minimum times. These can be subtracted from the profiling times
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* without much risk of reducing the profiling times below what they
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* would be when profiling is not configured. Abbreviate:
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* ab = minimum time between MC1 and MC3
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* a = minumum time between MC1 and MC2
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* b = minimum time between MC2 and MC3
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* cd = minimum time between ME1 and ME3
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* c = minimum time between ME1 and ME2
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* d = minimum time between ME2 and ME3.
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* These satisfy the relations:
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* ab <= mcount_overhead (just measured)
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* a + b <= ab
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* cd <= mexitcount_overhead (just measured)
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* c + d <= cd
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* a + d <= nullfunc_loop_profiled_time (just measured)
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* a >= 0, b >= 0, c >= 0, d >= 0.
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* Assume that ab and cd are equal to the minimums.
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*/
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p->cputime_overhead = CALIB_DOSCALE(cputime_overhead);
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p->mcount_overhead = CALIB_DOSCALE(mcount_overhead - cputime_overhead);
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p->mexitcount_overhead = CALIB_DOSCALE(mexitcount_overhead
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- cputime_overhead);
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nullfunc_loop_overhead = nullfunc_loop_profiled_time - empty_loop_time;
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p->mexitcount_post_overhead = CALIB_DOSCALE((mcount_overhead
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- nullfunc_loop_overhead)
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/ 4);
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p->mexitcount_pre_overhead = p->mexitcount_overhead
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+ p->cputime_overhead
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- p->mexitcount_post_overhead;
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p->mcount_pre_overhead = CALIB_DOSCALE(nullfunc_loop_overhead)
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- p->mexitcount_post_overhead;
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p->mcount_post_overhead = p->mcount_overhead
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+ p->cputime_overhead
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- p->mcount_pre_overhead;
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printf(
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"Profiling overheads: mcount: %d+%d, %d+%d; mexitcount: %d+%d, %d+%d nsec\n",
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c2n(p->cputime_overhead, p->profrate),
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c2n(p->mcount_overhead, p->profrate),
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c2n(p->mcount_pre_overhead, p->profrate),
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c2n(p->mcount_post_overhead, p->profrate),
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c2n(p->cputime_overhead, p->profrate),
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c2n(p->mexitcount_overhead, p->profrate),
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c2n(p->mexitcount_pre_overhead, p->profrate),
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c2n(p->mexitcount_post_overhead, p->profrate));
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printf(
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"Profiling overheads: mcount: %d+%d, %d+%d; mexitcount: %d+%d, %d+%d cycles\n",
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p->cputime_overhead, p->mcount_overhead,
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p->mcount_pre_overhead, p->mcount_post_overhead,
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p->cputime_overhead, p->mexitcount_overhead,
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p->mexitcount_pre_overhead, p->mexitcount_post_overhead);
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#endif /* GUPROF */
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}
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/*
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* Return kernel profiling information.
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*/
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static int
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sysctl_kern_prof(SYSCTL_HANDLER_ARGS)
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{
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int *name = (int *) arg1;
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u_int namelen = arg2;
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struct gmonparam *gp = &_gmonparam;
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int error;
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int state;
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/* all sysctl names at this level are terminal */
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if (namelen != 1)
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return (ENOTDIR); /* overloaded */
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switch (name[0]) {
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case GPROF_STATE:
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state = gp->state;
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error = sysctl_handle_int(oidp, &state, 0, req);
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if (error)
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return (error);
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if (!req->newptr)
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return (0);
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if (state == GMON_PROF_OFF) {
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gp->state = state;
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PROC_LOCK(&proc0);
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stopprofclock(&proc0);
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PROC_UNLOCK(&proc0);
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stopguprof(gp);
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} else if (state == GMON_PROF_ON) {
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gp->state = GMON_PROF_OFF;
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stopguprof(gp);
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gp->profrate = profhz;
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PROC_LOCK(&proc0);
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startprofclock(&proc0);
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PROC_UNLOCK(&proc0);
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gp->state = state;
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#ifdef GUPROF
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} else if (state == GMON_PROF_HIRES) {
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gp->state = GMON_PROF_OFF;
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PROC_LOCK(&proc0);
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stopprofclock(&proc0);
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PROC_UNLOCK(&proc0);
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startguprof(gp);
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gp->state = state;
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#endif
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} else if (state != gp->state)
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return (EINVAL);
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return (0);
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case GPROF_COUNT:
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return (sysctl_handle_opaque(oidp,
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gp->kcount, gp->kcountsize, req));
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case GPROF_FROMS:
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return (sysctl_handle_opaque(oidp,
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gp->froms, gp->fromssize, req));
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case GPROF_TOS:
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return (sysctl_handle_opaque(oidp,
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gp->tos, gp->tossize, req));
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case GPROF_GMONPARAM:
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return (sysctl_handle_opaque(oidp, gp, sizeof *gp, req));
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default:
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return (EOPNOTSUPP);
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}
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/* NOTREACHED */
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}
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SYSCTL_NODE(_kern, KERN_PROF, prof, CTLFLAG_RW, sysctl_kern_prof, "");
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#endif /* GPROF */
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/*
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* Profiling system call.
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*
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* The scale factor is a fixed point number with 16 bits of fraction, so that
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* 1.0 is represented as 0x10000. A scale factor of 0 turns off profiling.
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*/
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#ifndef _SYS_SYSPROTO_H_
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struct profil_args {
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caddr_t samples;
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size_t size;
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size_t offset;
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u_int scale;
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};
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#endif
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/* ARGSUSED */
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int
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profil(td, uap)
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struct thread *td;
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register struct profil_args *uap;
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{
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struct uprof *upp;
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struct proc *p;
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if (uap->scale > (1 << 16))
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return (EINVAL);
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p = td->td_proc;
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if (uap->scale == 0) {
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PROC_LOCK(p);
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stopprofclock(p);
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PROC_UNLOCK(p);
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return (0);
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}
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PROC_LOCK(p);
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upp = &td->td_proc->p_stats->p_prof;
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mtx_lock_spin(&sched_lock);
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upp->pr_off = uap->offset;
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upp->pr_scale = uap->scale;
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upp->pr_base = uap->samples;
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upp->pr_size = uap->size;
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mtx_unlock_spin(&sched_lock);
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startprofclock(p);
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PROC_UNLOCK(p);
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return (0);
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}
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/*
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* Scale is a fixed-point number with the binary point 16 bits
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* into the value, and is <= 1.0. pc is at most 32 bits, so the
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* intermediate result is at most 48 bits.
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*/
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#define PC_TO_INDEX(pc, prof) \
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((int)(((u_quad_t)((pc) - (prof)->pr_off) * \
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(u_quad_t)((prof)->pr_scale)) >> 16) & ~1)
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/*
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* Collect user-level profiling statistics; called on a profiling tick,
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* when a process is running in user-mode. This routine may be called
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* from an interrupt context. We try to update the user profiling buffers
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* cheaply with fuswintr() and suswintr(). If that fails, we revert to
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* an AST that will vector us to trap() with a context in which copyin
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|
* and copyout will work. Trap will then call addupc_task().
|
|
*
|
|
* Note that we may (rarely) not get around to the AST soon enough, and
|
|
* lose profile ticks when the next tick overwrites this one, but in this
|
|
* case the system is overloaded and the profile is probably already
|
|
* inaccurate.
|
|
*/
|
|
void
|
|
addupc_intr(struct thread *td, uintfptr_t pc, u_int ticks)
|
|
{
|
|
struct uprof *prof;
|
|
caddr_t addr;
|
|
u_int i;
|
|
int v;
|
|
|
|
if (ticks == 0)
|
|
return;
|
|
prof = &td->td_proc->p_stats->p_prof;
|
|
mtx_lock_spin(&sched_lock);
|
|
if (pc < prof->pr_off ||
|
|
(i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) {
|
|
mtx_unlock_spin(&sched_lock);
|
|
return; /* out of range; ignore */
|
|
}
|
|
|
|
addr = prof->pr_base + i;
|
|
mtx_unlock_spin(&sched_lock);
|
|
if ((v = fuswintr(addr)) == -1 || suswintr(addr, v + ticks) == -1) {
|
|
td->td_profil_addr = pc;
|
|
td->td_profil_ticks = ticks;
|
|
td->td_pflags |= TDP_OWEUPC;
|
|
mtx_lock_spin(&sched_lock);
|
|
td->td_flags |= TDF_ASTPENDING;
|
|
mtx_unlock_spin(&sched_lock);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Much like before, but we can afford to take faults here. If the
|
|
* update fails, we simply turn off profiling.
|
|
*/
|
|
void
|
|
addupc_task(struct thread *td, uintfptr_t pc, u_int ticks)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
struct uprof *prof;
|
|
caddr_t addr;
|
|
u_int i;
|
|
u_short v;
|
|
int stop = 0;
|
|
|
|
if (ticks == 0)
|
|
return;
|
|
|
|
PROC_LOCK(p);
|
|
if (!(p->p_flag & P_PROFIL)) {
|
|
PROC_UNLOCK(p);
|
|
return;
|
|
}
|
|
p->p_profthreads++;
|
|
prof = &p->p_stats->p_prof;
|
|
if (pc < prof->pr_off ||
|
|
(i = PC_TO_INDEX(pc, prof)) >= prof->pr_size) {
|
|
goto out;
|
|
}
|
|
|
|
addr = prof->pr_base + i;
|
|
PROC_UNLOCK(p);
|
|
if (copyin(addr, &v, sizeof(v)) == 0) {
|
|
v += ticks;
|
|
if (copyout(&v, addr, sizeof(v)) == 0) {
|
|
PROC_LOCK(p);
|
|
goto out;
|
|
}
|
|
}
|
|
stop = 1;
|
|
PROC_LOCK(p);
|
|
|
|
out:
|
|
if (--p->p_profthreads == 0) {
|
|
if (p->p_flag & P_STOPPROF) {
|
|
wakeup(&p->p_profthreads);
|
|
stop = 0;
|
|
}
|
|
}
|
|
if (stop)
|
|
stopprofclock(p);
|
|
PROC_UNLOCK(p);
|
|
}
|
|
|
|
#if (defined(__amd64__) || defined(__i386__)) && \
|
|
defined(__GNUCLIKE_CTOR_SECTION_HANDLING)
|
|
/*
|
|
* Support for "--test-coverage --profile-arcs" in GCC.
|
|
*
|
|
* We need to call all the functions in the .ctor section, in order
|
|
* to get all the counter-arrays strung into a list.
|
|
*
|
|
* XXX: the .ctors call __bb_init_func which is located in over in
|
|
* XXX: i386/i386/support.s for historical reasons. There is probably
|
|
* XXX: no reason for that to be assembler anymore, but doing it right
|
|
* XXX: in MI C code requires one to reverse-engineer the type-selection
|
|
* XXX: inside GCC. Have fun.
|
|
*
|
|
* XXX: Worrisome perspective: Calling the .ctors may make C++ in the
|
|
* XXX: kernel feasible. Don't.
|
|
*/
|
|
typedef void (*ctor_t)(void);
|
|
extern ctor_t _start_ctors, _stop_ctors;
|
|
|
|
static void
|
|
tcov_init(void *foo __unused)
|
|
{
|
|
ctor_t *p, q;
|
|
|
|
for (p = &_start_ctors; p < &_stop_ctors; p++) {
|
|
q = *p;
|
|
q();
|
|
}
|
|
}
|
|
|
|
SYSINIT(tcov_init, SI_SUB_KPROF, SI_ORDER_SECOND, tcov_init, NULL)
|
|
|
|
/*
|
|
* GCC contains magic to recognize calls to for instance execve() and
|
|
* puts in calls to this function to preserve the profile counters.
|
|
* XXX: Put zinging punchline here.
|
|
*/
|
|
void __bb_fork_func(void);
|
|
void
|
|
__bb_fork_func(void)
|
|
{
|
|
}
|
|
|
|
#endif
|
|
|