freebsd-dev/sys/kern/kern_et.c

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Implement new event timers infrastructure. It provides unified APIs for writing event timer drivers, for choosing best possible drivers by machine independent code and for operating them to supply kernel with hardclock(), statclock() and profclock() events in unified fashion on various hardware. Infrastructure provides support for both per-CPU (independent for every CPU core) and global timers in periodic and one-shot modes. MI management code at this moment uses only periodic mode, but one-shot mode use planned for later, as part of tickless kernel project. For this moment infrastructure used on i386 and amd64 architectures. Other archs are welcome to follow, while their current operation should not be affected. This patch updates existing drivers (i8254, RTC and LAPIC) for the new order, and adds event timers support into the HPET driver. These drivers have different capabilities: LAPIC - per-CPU timer, supports periodic and one-shot operation, may freeze in C3 state, calibrated on first use, so may be not exactly precise. HPET - depending on hardware can work as per-CPU or global, supports periodic and one-shot operation, usually provides several event timers. i8254 - global, limited to periodic mode, because same hardware used also as time counter. RTC - global, supports only periodic mode, set of frequencies in Hz limited by powers of 2. Depending on hardware capabilities, drivers preferred in following orders, either LAPIC, HPETs, i8254, RTC or HPETs, LAPIC, i8254, RTC. User may explicitly specify wanted timers via loader tunables or sysctls: kern.eventtimer.timer1 and kern.eventtimer.timer2. If requested driver is unavailable or unoperational, system will try to replace it. If no more timers available or "NONE" specified for second, system will operate using only one timer, multiplying it's frequency by few times and uing respective dividers to honor hz, stathz and profhz values, set during initial setup.
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/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2010-2013 Alexander Motin <mav@FreeBSD.org>
Implement new event timers infrastructure. It provides unified APIs for writing event timer drivers, for choosing best possible drivers by machine independent code and for operating them to supply kernel with hardclock(), statclock() and profclock() events in unified fashion on various hardware. Infrastructure provides support for both per-CPU (independent for every CPU core) and global timers in periodic and one-shot modes. MI management code at this moment uses only periodic mode, but one-shot mode use planned for later, as part of tickless kernel project. For this moment infrastructure used on i386 and amd64 architectures. Other archs are welcome to follow, while their current operation should not be affected. This patch updates existing drivers (i8254, RTC and LAPIC) for the new order, and adds event timers support into the HPET driver. These drivers have different capabilities: LAPIC - per-CPU timer, supports periodic and one-shot operation, may freeze in C3 state, calibrated on first use, so may be not exactly precise. HPET - depending on hardware can work as per-CPU or global, supports periodic and one-shot operation, usually provides several event timers. i8254 - global, limited to periodic mode, because same hardware used also as time counter. RTC - global, supports only periodic mode, set of frequencies in Hz limited by powers of 2. Depending on hardware capabilities, drivers preferred in following orders, either LAPIC, HPETs, i8254, RTC or HPETs, LAPIC, i8254, RTC. User may explicitly specify wanted timers via loader tunables or sysctls: kern.eventtimer.timer1 and kern.eventtimer.timer2. If requested driver is unavailable or unoperational, system will try to replace it. If no more timers available or "NONE" specified for second, system will operate using only one timer, multiplying it's frequency by few times and uing respective dividers to honor hz, stathz and profhz values, set during initial setup.
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* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer,
* without modification, immediately at the beginning of the file.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/sbuf.h>
Implement new event timers infrastructure. It provides unified APIs for writing event timer drivers, for choosing best possible drivers by machine independent code and for operating them to supply kernel with hardclock(), statclock() and profclock() events in unified fashion on various hardware. Infrastructure provides support for both per-CPU (independent for every CPU core) and global timers in periodic and one-shot modes. MI management code at this moment uses only periodic mode, but one-shot mode use planned for later, as part of tickless kernel project. For this moment infrastructure used on i386 and amd64 architectures. Other archs are welcome to follow, while their current operation should not be affected. This patch updates existing drivers (i8254, RTC and LAPIC) for the new order, and adds event timers support into the HPET driver. These drivers have different capabilities: LAPIC - per-CPU timer, supports periodic and one-shot operation, may freeze in C3 state, calibrated on first use, so may be not exactly precise. HPET - depending on hardware can work as per-CPU or global, supports periodic and one-shot operation, usually provides several event timers. i8254 - global, limited to periodic mode, because same hardware used also as time counter. RTC - global, supports only periodic mode, set of frequencies in Hz limited by powers of 2. Depending on hardware capabilities, drivers preferred in following orders, either LAPIC, HPETs, i8254, RTC or HPETs, LAPIC, i8254, RTC. User may explicitly specify wanted timers via loader tunables or sysctls: kern.eventtimer.timer1 and kern.eventtimer.timer2. If requested driver is unavailable or unoperational, system will try to replace it. If no more timers available or "NONE" specified for second, system will operate using only one timer, multiplying it's frequency by few times and uing respective dividers to honor hz, stathz and profhz values, set during initial setup.
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#include <sys/sysctl.h>
#include <sys/systm.h>
#include <sys/queue.h>
#include <sys/timeet.h>
#include "opt_timer.h"
Implement new event timers infrastructure. It provides unified APIs for writing event timer drivers, for choosing best possible drivers by machine independent code and for operating them to supply kernel with hardclock(), statclock() and profclock() events in unified fashion on various hardware. Infrastructure provides support for both per-CPU (independent for every CPU core) and global timers in periodic and one-shot modes. MI management code at this moment uses only periodic mode, but one-shot mode use planned for later, as part of tickless kernel project. For this moment infrastructure used on i386 and amd64 architectures. Other archs are welcome to follow, while their current operation should not be affected. This patch updates existing drivers (i8254, RTC and LAPIC) for the new order, and adds event timers support into the HPET driver. These drivers have different capabilities: LAPIC - per-CPU timer, supports periodic and one-shot operation, may freeze in C3 state, calibrated on first use, so may be not exactly precise. HPET - depending on hardware can work as per-CPU or global, supports periodic and one-shot operation, usually provides several event timers. i8254 - global, limited to periodic mode, because same hardware used also as time counter. RTC - global, supports only periodic mode, set of frequencies in Hz limited by powers of 2. Depending on hardware capabilities, drivers preferred in following orders, either LAPIC, HPETs, i8254, RTC or HPETs, LAPIC, i8254, RTC. User may explicitly specify wanted timers via loader tunables or sysctls: kern.eventtimer.timer1 and kern.eventtimer.timer2. If requested driver is unavailable or unoperational, system will try to replace it. If no more timers available or "NONE" specified for second, system will operate using only one timer, multiplying it's frequency by few times and uing respective dividers to honor hz, stathz and profhz values, set during initial setup.
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SLIST_HEAD(et_eventtimers_list, eventtimer);
static struct et_eventtimers_list eventtimers = SLIST_HEAD_INITIALIZER(et_eventtimers);
struct mtx et_eventtimers_mtx;
Refactor timer management code with priority to one-shot operation mode. The main goal of this is to generate timer interrupts only when there is some work to do. When CPU is busy interrupts are generating at full rate of hz + stathz to fullfill scheduler and timekeeping requirements. But when CPU is idle, only minimum set of interrupts (down to 8 interrupts per second per CPU now), needed to handle scheduled callouts is executed. This allows significantly increase idle CPU sleep time, increasing effect of static power-saving technologies. Also it should reduce host CPU load on virtualized systems, when guest system is idle. There is set of tunables, also available as writable sysctls, allowing to control wanted event timer subsystem behavior: kern.eventtimer.timer - allows to choose event timer hardware to use. On x86 there is up to 4 different kinds of timers. Depending on whether chosen timer is per-CPU, behavior of other options slightly differs. kern.eventtimer.periodic - allows to choose periodic and one-shot operation mode. In periodic mode, current timer hardware taken as the only source of time for time events. This mode is quite alike to previous kernel behavior. One-shot mode instead uses currently selected time counter hardware to schedule all needed events one by one and program timer to generate interrupt exactly in specified time. Default value depends of chosen timer capabilities, but one-shot mode is preferred, until other is forced by user or hardware. kern.eventtimer.singlemul - in periodic mode specifies how much times higher timer frequency should be, to not strictly alias hardclock() and statclock() events. Default values are 2 and 4, but could be reduced to 1 if extra interrupts are unwanted. kern.eventtimer.idletick - makes each CPU to receive every timer interrupt independently of whether they busy or not. By default this options is disabled. If chosen timer is per-CPU and runs in periodic mode, this option has no effect - all interrupts are generating. As soon as this patch modifies cpu_idle() on some platforms, I have also refactored one on x86. Now it makes use of MONITOR/MWAIT instrunctions (if supported) under high sleep/wakeup rate, as fast alternative to other methods. It allows SMP scheduler to wake up sleeping CPUs much faster without using IPI, significantly increasing performance on some highly task-switching loads. Tested by: many (on i386, amd64, sparc64 and powerc) H/W donated by: Gheorghe Ardelean Sponsored by: iXsystems, Inc.
2010-09-13 07:25:35 +00:00
MTX_SYSINIT(et_eventtimers_init, &et_eventtimers_mtx, "et_mtx", MTX_DEF);
Implement new event timers infrastructure. It provides unified APIs for writing event timer drivers, for choosing best possible drivers by machine independent code and for operating them to supply kernel with hardclock(), statclock() and profclock() events in unified fashion on various hardware. Infrastructure provides support for both per-CPU (independent for every CPU core) and global timers in periodic and one-shot modes. MI management code at this moment uses only periodic mode, but one-shot mode use planned for later, as part of tickless kernel project. For this moment infrastructure used on i386 and amd64 architectures. Other archs are welcome to follow, while their current operation should not be affected. This patch updates existing drivers (i8254, RTC and LAPIC) for the new order, and adds event timers support into the HPET driver. These drivers have different capabilities: LAPIC - per-CPU timer, supports periodic and one-shot operation, may freeze in C3 state, calibrated on first use, so may be not exactly precise. HPET - depending on hardware can work as per-CPU or global, supports periodic and one-shot operation, usually provides several event timers. i8254 - global, limited to periodic mode, because same hardware used also as time counter. RTC - global, supports only periodic mode, set of frequencies in Hz limited by powers of 2. Depending on hardware capabilities, drivers preferred in following orders, either LAPIC, HPETs, i8254, RTC or HPETs, LAPIC, i8254, RTC. User may explicitly specify wanted timers via loader tunables or sysctls: kern.eventtimer.timer1 and kern.eventtimer.timer2. If requested driver is unavailable or unoperational, system will try to replace it. If no more timers available or "NONE" specified for second, system will operate using only one timer, multiplying it's frequency by few times and uing respective dividers to honor hz, stathz and profhz values, set during initial setup.
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SYSCTL_NODE(_kern, OID_AUTO, eventtimer, CTLFLAG_RW, 0, "Event timers");
static SYSCTL_NODE(_kern_eventtimer, OID_AUTO, et, CTLFLAG_RW, 0, "");
Implement new event timers infrastructure. It provides unified APIs for writing event timer drivers, for choosing best possible drivers by machine independent code and for operating them to supply kernel with hardclock(), statclock() and profclock() events in unified fashion on various hardware. Infrastructure provides support for both per-CPU (independent for every CPU core) and global timers in periodic and one-shot modes. MI management code at this moment uses only periodic mode, but one-shot mode use planned for later, as part of tickless kernel project. For this moment infrastructure used on i386 and amd64 architectures. Other archs are welcome to follow, while their current operation should not be affected. This patch updates existing drivers (i8254, RTC and LAPIC) for the new order, and adds event timers support into the HPET driver. These drivers have different capabilities: LAPIC - per-CPU timer, supports periodic and one-shot operation, may freeze in C3 state, calibrated on first use, so may be not exactly precise. HPET - depending on hardware can work as per-CPU or global, supports periodic and one-shot operation, usually provides several event timers. i8254 - global, limited to periodic mode, because same hardware used also as time counter. RTC - global, supports only periodic mode, set of frequencies in Hz limited by powers of 2. Depending on hardware capabilities, drivers preferred in following orders, either LAPIC, HPETs, i8254, RTC or HPETs, LAPIC, i8254, RTC. User may explicitly specify wanted timers via loader tunables or sysctls: kern.eventtimer.timer1 and kern.eventtimer.timer2. If requested driver is unavailable or unoperational, system will try to replace it. If no more timers available or "NONE" specified for second, system will operate using only one timer, multiplying it's frequency by few times and uing respective dividers to honor hz, stathz and profhz values, set during initial setup.
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/*
* Register a new event timer hardware.
*/
int
et_register(struct eventtimer *et)
{
struct eventtimer *tmp, *next;
if (et->et_quality >= 0 || bootverbose) {
if (et->et_frequency == 0) {
printf("Event timer \"%s\" quality %d\n",
et->et_name, et->et_quality);
} else {
printf("Event timer \"%s\" "
"frequency %ju Hz quality %d\n",
et->et_name, (uintmax_t)et->et_frequency,
et->et_quality);
}
Implement new event timers infrastructure. It provides unified APIs for writing event timer drivers, for choosing best possible drivers by machine independent code and for operating them to supply kernel with hardclock(), statclock() and profclock() events in unified fashion on various hardware. Infrastructure provides support for both per-CPU (independent for every CPU core) and global timers in periodic and one-shot modes. MI management code at this moment uses only periodic mode, but one-shot mode use planned for later, as part of tickless kernel project. For this moment infrastructure used on i386 and amd64 architectures. Other archs are welcome to follow, while their current operation should not be affected. This patch updates existing drivers (i8254, RTC and LAPIC) for the new order, and adds event timers support into the HPET driver. These drivers have different capabilities: LAPIC - per-CPU timer, supports periodic and one-shot operation, may freeze in C3 state, calibrated on first use, so may be not exactly precise. HPET - depending on hardware can work as per-CPU or global, supports periodic and one-shot operation, usually provides several event timers. i8254 - global, limited to periodic mode, because same hardware used also as time counter. RTC - global, supports only periodic mode, set of frequencies in Hz limited by powers of 2. Depending on hardware capabilities, drivers preferred in following orders, either LAPIC, HPETs, i8254, RTC or HPETs, LAPIC, i8254, RTC. User may explicitly specify wanted timers via loader tunables or sysctls: kern.eventtimer.timer1 and kern.eventtimer.timer2. If requested driver is unavailable or unoperational, system will try to replace it. If no more timers available or "NONE" specified for second, system will operate using only one timer, multiplying it's frequency by few times and uing respective dividers to honor hz, stathz and profhz values, set during initial setup.
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}
KASSERT(et->et_start, ("et_register: timer has no start function"));
et->et_sysctl = SYSCTL_ADD_NODE_WITH_LABEL(NULL,
Implement new event timers infrastructure. It provides unified APIs for writing event timer drivers, for choosing best possible drivers by machine independent code and for operating them to supply kernel with hardclock(), statclock() and profclock() events in unified fashion on various hardware. Infrastructure provides support for both per-CPU (independent for every CPU core) and global timers in periodic and one-shot modes. MI management code at this moment uses only periodic mode, but one-shot mode use planned for later, as part of tickless kernel project. For this moment infrastructure used on i386 and amd64 architectures. Other archs are welcome to follow, while their current operation should not be affected. This patch updates existing drivers (i8254, RTC and LAPIC) for the new order, and adds event timers support into the HPET driver. These drivers have different capabilities: LAPIC - per-CPU timer, supports periodic and one-shot operation, may freeze in C3 state, calibrated on first use, so may be not exactly precise. HPET - depending on hardware can work as per-CPU or global, supports periodic and one-shot operation, usually provides several event timers. i8254 - global, limited to periodic mode, because same hardware used also as time counter. RTC - global, supports only periodic mode, set of frequencies in Hz limited by powers of 2. Depending on hardware capabilities, drivers preferred in following orders, either LAPIC, HPETs, i8254, RTC or HPETs, LAPIC, i8254, RTC. User may explicitly specify wanted timers via loader tunables or sysctls: kern.eventtimer.timer1 and kern.eventtimer.timer2. If requested driver is unavailable or unoperational, system will try to replace it. If no more timers available or "NONE" specified for second, system will operate using only one timer, multiplying it's frequency by few times and uing respective dividers to honor hz, stathz and profhz values, set during initial setup.
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SYSCTL_STATIC_CHILDREN(_kern_eventtimer_et), OID_AUTO, et->et_name,
CTLFLAG_RW, 0, "event timer description", "eventtimer");
SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(et->et_sysctl), OID_AUTO,
Implement new event timers infrastructure. It provides unified APIs for writing event timer drivers, for choosing best possible drivers by machine independent code and for operating them to supply kernel with hardclock(), statclock() and profclock() events in unified fashion on various hardware. Infrastructure provides support for both per-CPU (independent for every CPU core) and global timers in periodic and one-shot modes. MI management code at this moment uses only periodic mode, but one-shot mode use planned for later, as part of tickless kernel project. For this moment infrastructure used on i386 and amd64 architectures. Other archs are welcome to follow, while their current operation should not be affected. This patch updates existing drivers (i8254, RTC and LAPIC) for the new order, and adds event timers support into the HPET driver. These drivers have different capabilities: LAPIC - per-CPU timer, supports periodic and one-shot operation, may freeze in C3 state, calibrated on first use, so may be not exactly precise. HPET - depending on hardware can work as per-CPU or global, supports periodic and one-shot operation, usually provides several event timers. i8254 - global, limited to periodic mode, because same hardware used also as time counter. RTC - global, supports only periodic mode, set of frequencies in Hz limited by powers of 2. Depending on hardware capabilities, drivers preferred in following orders, either LAPIC, HPETs, i8254, RTC or HPETs, LAPIC, i8254, RTC. User may explicitly specify wanted timers via loader tunables or sysctls: kern.eventtimer.timer1 and kern.eventtimer.timer2. If requested driver is unavailable or unoperational, system will try to replace it. If no more timers available or "NONE" specified for second, system will operate using only one timer, multiplying it's frequency by few times and uing respective dividers to honor hz, stathz and profhz values, set during initial setup.
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"flags", CTLFLAG_RD, &(et->et_flags), 0,
"Event timer capabilities");
SYSCTL_ADD_UQUAD(NULL, SYSCTL_CHILDREN(et->et_sysctl), OID_AUTO,
"frequency", CTLFLAG_RD, &(et->et_frequency),
Implement new event timers infrastructure. It provides unified APIs for writing event timer drivers, for choosing best possible drivers by machine independent code and for operating them to supply kernel with hardclock(), statclock() and profclock() events in unified fashion on various hardware. Infrastructure provides support for both per-CPU (independent for every CPU core) and global timers in periodic and one-shot modes. MI management code at this moment uses only periodic mode, but one-shot mode use planned for later, as part of tickless kernel project. For this moment infrastructure used on i386 and amd64 architectures. Other archs are welcome to follow, while their current operation should not be affected. This patch updates existing drivers (i8254, RTC and LAPIC) for the new order, and adds event timers support into the HPET driver. These drivers have different capabilities: LAPIC - per-CPU timer, supports periodic and one-shot operation, may freeze in C3 state, calibrated on first use, so may be not exactly precise. HPET - depending on hardware can work as per-CPU or global, supports periodic and one-shot operation, usually provides several event timers. i8254 - global, limited to periodic mode, because same hardware used also as time counter. RTC - global, supports only periodic mode, set of frequencies in Hz limited by powers of 2. Depending on hardware capabilities, drivers preferred in following orders, either LAPIC, HPETs, i8254, RTC or HPETs, LAPIC, i8254, RTC. User may explicitly specify wanted timers via loader tunables or sysctls: kern.eventtimer.timer1 and kern.eventtimer.timer2. If requested driver is unavailable or unoperational, system will try to replace it. If no more timers available or "NONE" specified for second, system will operate using only one timer, multiplying it's frequency by few times and uing respective dividers to honor hz, stathz and profhz values, set during initial setup.
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"Event timer base frequency");
SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(et->et_sysctl), OID_AUTO,
"quality", CTLFLAG_RD, &(et->et_quality), 0,
"Goodness of event timer");
ET_LOCK();
if (SLIST_EMPTY(&eventtimers) ||
SLIST_FIRST(&eventtimers)->et_quality < et->et_quality) {
SLIST_INSERT_HEAD(&eventtimers, et, et_all);
} else {
SLIST_FOREACH(tmp, &eventtimers, et_all) {
next = SLIST_NEXT(tmp, et_all);
if (next == NULL || next->et_quality < et->et_quality) {
SLIST_INSERT_AFTER(tmp, et, et_all);
break;
}
}
}
ET_UNLOCK();
return (0);
}
/*
* Deregister event timer hardware.
*/
int
et_deregister(struct eventtimer *et)
{
int err = 0;
if (et->et_deregister_cb != NULL) {
if ((err = et->et_deregister_cb(et, et->et_arg)) != 0)
return (err);
}
ET_LOCK();
SLIST_REMOVE(&eventtimers, et, eventtimer, et_all);
ET_UNLOCK();
sysctl_remove_oid(et->et_sysctl, 1, 1);
return (0);
}
/*
* Change the frequency of the given timer. If it is the active timer,
* reconfigure it on all CPUs (reschedules all current events based on the new
* timer frequency).
*/
void
et_change_frequency(struct eventtimer *et, uint64_t newfreq)
{
#ifndef NO_EVENTTIMERS
cpu_et_frequency(et, newfreq);
#endif
}
Implement new event timers infrastructure. It provides unified APIs for writing event timer drivers, for choosing best possible drivers by machine independent code and for operating them to supply kernel with hardclock(), statclock() and profclock() events in unified fashion on various hardware. Infrastructure provides support for both per-CPU (independent for every CPU core) and global timers in periodic and one-shot modes. MI management code at this moment uses only periodic mode, but one-shot mode use planned for later, as part of tickless kernel project. For this moment infrastructure used on i386 and amd64 architectures. Other archs are welcome to follow, while their current operation should not be affected. This patch updates existing drivers (i8254, RTC and LAPIC) for the new order, and adds event timers support into the HPET driver. These drivers have different capabilities: LAPIC - per-CPU timer, supports periodic and one-shot operation, may freeze in C3 state, calibrated on first use, so may be not exactly precise. HPET - depending on hardware can work as per-CPU or global, supports periodic and one-shot operation, usually provides several event timers. i8254 - global, limited to periodic mode, because same hardware used also as time counter. RTC - global, supports only periodic mode, set of frequencies in Hz limited by powers of 2. Depending on hardware capabilities, drivers preferred in following orders, either LAPIC, HPETs, i8254, RTC or HPETs, LAPIC, i8254, RTC. User may explicitly specify wanted timers via loader tunables or sysctls: kern.eventtimer.timer1 and kern.eventtimer.timer2. If requested driver is unavailable or unoperational, system will try to replace it. If no more timers available or "NONE" specified for second, system will operate using only one timer, multiplying it's frequency by few times and uing respective dividers to honor hz, stathz and profhz values, set during initial setup.
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/*
* Find free event timer hardware with specified parameters.
*/
struct eventtimer *
et_find(const char *name, int check, int want)
{
struct eventtimer *et = NULL;
SLIST_FOREACH(et, &eventtimers, et_all) {
if (et->et_active)
continue;
if (name != NULL && strcasecmp(et->et_name, name) != 0)
continue;
if (name == NULL && et->et_quality < 0)
continue;
if ((et->et_flags & check) != want)
continue;
break;
}
return (et);
}
/*
* Initialize event timer hardware. Set callbacks.
*/
int
et_init(struct eventtimer *et, et_event_cb_t *event,
et_deregister_cb_t *deregister, void *arg)
{
if (event == NULL)
return (EINVAL);
if (et->et_active)
return (EBUSY);
et->et_active = 1;
et->et_event_cb = event;
et->et_deregister_cb = deregister;
et->et_arg = arg;
return (0);
}
/*
* Start event timer hardware.
* first - delay before first tick.
* period - period of subsequent periodic ticks.
*/
int
et_start(struct eventtimer *et, sbintime_t first, sbintime_t period)
Implement new event timers infrastructure. It provides unified APIs for writing event timer drivers, for choosing best possible drivers by machine independent code and for operating them to supply kernel with hardclock(), statclock() and profclock() events in unified fashion on various hardware. Infrastructure provides support for both per-CPU (independent for every CPU core) and global timers in periodic and one-shot modes. MI management code at this moment uses only periodic mode, but one-shot mode use planned for later, as part of tickless kernel project. For this moment infrastructure used on i386 and amd64 architectures. Other archs are welcome to follow, while their current operation should not be affected. This patch updates existing drivers (i8254, RTC and LAPIC) for the new order, and adds event timers support into the HPET driver. These drivers have different capabilities: LAPIC - per-CPU timer, supports periodic and one-shot operation, may freeze in C3 state, calibrated on first use, so may be not exactly precise. HPET - depending on hardware can work as per-CPU or global, supports periodic and one-shot operation, usually provides several event timers. i8254 - global, limited to periodic mode, because same hardware used also as time counter. RTC - global, supports only periodic mode, set of frequencies in Hz limited by powers of 2. Depending on hardware capabilities, drivers preferred in following orders, either LAPIC, HPETs, i8254, RTC or HPETs, LAPIC, i8254, RTC. User may explicitly specify wanted timers via loader tunables or sysctls: kern.eventtimer.timer1 and kern.eventtimer.timer2. If requested driver is unavailable or unoperational, system will try to replace it. If no more timers available or "NONE" specified for second, system will operate using only one timer, multiplying it's frequency by few times and uing respective dividers to honor hz, stathz and profhz values, set during initial setup.
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{
if (!et->et_active)
return (ENXIO);
KASSERT(period >= 0, ("et_start: negative period"));
KASSERT((et->et_flags & ET_FLAGS_PERIODIC) || period == 0,
("et_start: period specified for oneshot-only timer"));
KASSERT((et->et_flags & ET_FLAGS_ONESHOT) || period != 0,
("et_start: period not specified for periodic-only timer"));
if (period != 0) {
if (period < et->et_min_period)
period = et->et_min_period;
else if (period > et->et_max_period)
period = et->et_max_period;
}
if (period == 0 || first != 0) {
if (first < et->et_min_period)
first = et->et_min_period;
else if (first > et->et_max_period)
first = et->et_max_period;
}
return (et->et_start(et, first, period));
Implement new event timers infrastructure. It provides unified APIs for writing event timer drivers, for choosing best possible drivers by machine independent code and for operating them to supply kernel with hardclock(), statclock() and profclock() events in unified fashion on various hardware. Infrastructure provides support for both per-CPU (independent for every CPU core) and global timers in periodic and one-shot modes. MI management code at this moment uses only periodic mode, but one-shot mode use planned for later, as part of tickless kernel project. For this moment infrastructure used on i386 and amd64 architectures. Other archs are welcome to follow, while their current operation should not be affected. This patch updates existing drivers (i8254, RTC and LAPIC) for the new order, and adds event timers support into the HPET driver. These drivers have different capabilities: LAPIC - per-CPU timer, supports periodic and one-shot operation, may freeze in C3 state, calibrated on first use, so may be not exactly precise. HPET - depending on hardware can work as per-CPU or global, supports periodic and one-shot operation, usually provides several event timers. i8254 - global, limited to periodic mode, because same hardware used also as time counter. RTC - global, supports only periodic mode, set of frequencies in Hz limited by powers of 2. Depending on hardware capabilities, drivers preferred in following orders, either LAPIC, HPETs, i8254, RTC or HPETs, LAPIC, i8254, RTC. User may explicitly specify wanted timers via loader tunables or sysctls: kern.eventtimer.timer1 and kern.eventtimer.timer2. If requested driver is unavailable or unoperational, system will try to replace it. If no more timers available or "NONE" specified for second, system will operate using only one timer, multiplying it's frequency by few times and uing respective dividers to honor hz, stathz and profhz values, set during initial setup.
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}
/* Stop event timer hardware. */
int
et_stop(struct eventtimer *et)
{
if (!et->et_active)
return (ENXIO);
if (et->et_stop)
return (et->et_stop(et));
return (0);
}
/* Mark event timer hardware as broken. */
int
et_ban(struct eventtimer *et)
{
et->et_flags &= ~(ET_FLAGS_PERIODIC | ET_FLAGS_ONESHOT);
return (0);
}
/* Free event timer hardware. */
int
et_free(struct eventtimer *et)
{
if (!et->et_active)
return (ENXIO);
et->et_active = 0;
return (0);
}
/* Report list of supported event timer hardware via sysctl. */
Implement new event timers infrastructure. It provides unified APIs for writing event timer drivers, for choosing best possible drivers by machine independent code and for operating them to supply kernel with hardclock(), statclock() and profclock() events in unified fashion on various hardware. Infrastructure provides support for both per-CPU (independent for every CPU core) and global timers in periodic and one-shot modes. MI management code at this moment uses only periodic mode, but one-shot mode use planned for later, as part of tickless kernel project. For this moment infrastructure used on i386 and amd64 architectures. Other archs are welcome to follow, while their current operation should not be affected. This patch updates existing drivers (i8254, RTC and LAPIC) for the new order, and adds event timers support into the HPET driver. These drivers have different capabilities: LAPIC - per-CPU timer, supports periodic and one-shot operation, may freeze in C3 state, calibrated on first use, so may be not exactly precise. HPET - depending on hardware can work as per-CPU or global, supports periodic and one-shot operation, usually provides several event timers. i8254 - global, limited to periodic mode, because same hardware used also as time counter. RTC - global, supports only periodic mode, set of frequencies in Hz limited by powers of 2. Depending on hardware capabilities, drivers preferred in following orders, either LAPIC, HPETs, i8254, RTC or HPETs, LAPIC, i8254, RTC. User may explicitly specify wanted timers via loader tunables or sysctls: kern.eventtimer.timer1 and kern.eventtimer.timer2. If requested driver is unavailable or unoperational, system will try to replace it. If no more timers available or "NONE" specified for second, system will operate using only one timer, multiplying it's frequency by few times and uing respective dividers to honor hz, stathz and profhz values, set during initial setup.
2010-06-20 21:33:29 +00:00
static int
sysctl_kern_eventtimer_choice(SYSCTL_HANDLER_ARGS)
{
struct sbuf sb;
Implement new event timers infrastructure. It provides unified APIs for writing event timer drivers, for choosing best possible drivers by machine independent code and for operating them to supply kernel with hardclock(), statclock() and profclock() events in unified fashion on various hardware. Infrastructure provides support for both per-CPU (independent for every CPU core) and global timers in periodic and one-shot modes. MI management code at this moment uses only periodic mode, but one-shot mode use planned for later, as part of tickless kernel project. For this moment infrastructure used on i386 and amd64 architectures. Other archs are welcome to follow, while their current operation should not be affected. This patch updates existing drivers (i8254, RTC and LAPIC) for the new order, and adds event timers support into the HPET driver. These drivers have different capabilities: LAPIC - per-CPU timer, supports periodic and one-shot operation, may freeze in C3 state, calibrated on first use, so may be not exactly precise. HPET - depending on hardware can work as per-CPU or global, supports periodic and one-shot operation, usually provides several event timers. i8254 - global, limited to periodic mode, because same hardware used also as time counter. RTC - global, supports only periodic mode, set of frequencies in Hz limited by powers of 2. Depending on hardware capabilities, drivers preferred in following orders, either LAPIC, HPETs, i8254, RTC or HPETs, LAPIC, i8254, RTC. User may explicitly specify wanted timers via loader tunables or sysctls: kern.eventtimer.timer1 and kern.eventtimer.timer2. If requested driver is unavailable or unoperational, system will try to replace it. If no more timers available or "NONE" specified for second, system will operate using only one timer, multiplying it's frequency by few times and uing respective dividers to honor hz, stathz and profhz values, set during initial setup.
2010-06-20 21:33:29 +00:00
struct eventtimer *et;
int error;
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sbuf_new(&sb, NULL, 256, SBUF_AUTOEXTEND | SBUF_INCLUDENUL);
Implement new event timers infrastructure. It provides unified APIs for writing event timer drivers, for choosing best possible drivers by machine independent code and for operating them to supply kernel with hardclock(), statclock() and profclock() events in unified fashion on various hardware. Infrastructure provides support for both per-CPU (independent for every CPU core) and global timers in periodic and one-shot modes. MI management code at this moment uses only periodic mode, but one-shot mode use planned for later, as part of tickless kernel project. For this moment infrastructure used on i386 and amd64 architectures. Other archs are welcome to follow, while their current operation should not be affected. This patch updates existing drivers (i8254, RTC and LAPIC) for the new order, and adds event timers support into the HPET driver. These drivers have different capabilities: LAPIC - per-CPU timer, supports periodic and one-shot operation, may freeze in C3 state, calibrated on first use, so may be not exactly precise. HPET - depending on hardware can work as per-CPU or global, supports periodic and one-shot operation, usually provides several event timers. i8254 - global, limited to periodic mode, because same hardware used also as time counter. RTC - global, supports only periodic mode, set of frequencies in Hz limited by powers of 2. Depending on hardware capabilities, drivers preferred in following orders, either LAPIC, HPETs, i8254, RTC or HPETs, LAPIC, i8254, RTC. User may explicitly specify wanted timers via loader tunables or sysctls: kern.eventtimer.timer1 and kern.eventtimer.timer2. If requested driver is unavailable or unoperational, system will try to replace it. If no more timers available or "NONE" specified for second, system will operate using only one timer, multiplying it's frequency by few times and uing respective dividers to honor hz, stathz and profhz values, set during initial setup.
2010-06-20 21:33:29 +00:00
ET_LOCK();
SLIST_FOREACH(et, &eventtimers, et_all) {
if (et != SLIST_FIRST(&eventtimers))
sbuf_putc(&sb, ' ');
sbuf_printf(&sb, "%s(%d)", et->et_name, et->et_quality);
Implement new event timers infrastructure. It provides unified APIs for writing event timer drivers, for choosing best possible drivers by machine independent code and for operating them to supply kernel with hardclock(), statclock() and profclock() events in unified fashion on various hardware. Infrastructure provides support for both per-CPU (independent for every CPU core) and global timers in periodic and one-shot modes. MI management code at this moment uses only periodic mode, but one-shot mode use planned for later, as part of tickless kernel project. For this moment infrastructure used on i386 and amd64 architectures. Other archs are welcome to follow, while their current operation should not be affected. This patch updates existing drivers (i8254, RTC and LAPIC) for the new order, and adds event timers support into the HPET driver. These drivers have different capabilities: LAPIC - per-CPU timer, supports periodic and one-shot operation, may freeze in C3 state, calibrated on first use, so may be not exactly precise. HPET - depending on hardware can work as per-CPU or global, supports periodic and one-shot operation, usually provides several event timers. i8254 - global, limited to periodic mode, because same hardware used also as time counter. RTC - global, supports only periodic mode, set of frequencies in Hz limited by powers of 2. Depending on hardware capabilities, drivers preferred in following orders, either LAPIC, HPETs, i8254, RTC or HPETs, LAPIC, i8254, RTC. User may explicitly specify wanted timers via loader tunables or sysctls: kern.eventtimer.timer1 and kern.eventtimer.timer2. If requested driver is unavailable or unoperational, system will try to replace it. If no more timers available or "NONE" specified for second, system will operate using only one timer, multiplying it's frequency by few times and uing respective dividers to honor hz, stathz and profhz values, set during initial setup.
2010-06-20 21:33:29 +00:00
}
ET_UNLOCK();
error = sbuf_finish(&sb);
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if (error == 0)
error = SYSCTL_OUT(req, sbuf_data(&sb), sbuf_len(&sb));
sbuf_delete(&sb);
Implement new event timers infrastructure. It provides unified APIs for writing event timer drivers, for choosing best possible drivers by machine independent code and for operating them to supply kernel with hardclock(), statclock() and profclock() events in unified fashion on various hardware. Infrastructure provides support for both per-CPU (independent for every CPU core) and global timers in periodic and one-shot modes. MI management code at this moment uses only periodic mode, but one-shot mode use planned for later, as part of tickless kernel project. For this moment infrastructure used on i386 and amd64 architectures. Other archs are welcome to follow, while their current operation should not be affected. This patch updates existing drivers (i8254, RTC and LAPIC) for the new order, and adds event timers support into the HPET driver. These drivers have different capabilities: LAPIC - per-CPU timer, supports periodic and one-shot operation, may freeze in C3 state, calibrated on first use, so may be not exactly precise. HPET - depending on hardware can work as per-CPU or global, supports periodic and one-shot operation, usually provides several event timers. i8254 - global, limited to periodic mode, because same hardware used also as time counter. RTC - global, supports only periodic mode, set of frequencies in Hz limited by powers of 2. Depending on hardware capabilities, drivers preferred in following orders, either LAPIC, HPETs, i8254, RTC or HPETs, LAPIC, i8254, RTC. User may explicitly specify wanted timers via loader tunables or sysctls: kern.eventtimer.timer1 and kern.eventtimer.timer2. If requested driver is unavailable or unoperational, system will try to replace it. If no more timers available or "NONE" specified for second, system will operate using only one timer, multiplying it's frequency by few times and uing respective dividers to honor hz, stathz and profhz values, set during initial setup.
2010-06-20 21:33:29 +00:00
return (error);
}
SYSCTL_PROC(_kern_eventtimer, OID_AUTO, choice,
CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,
0, 0, sysctl_kern_eventtimer_choice, "A", "Present event timers");