Author: mav
Date: Wed Dec 14 15:19:40 2011
New Revision: 228501
URL: http://svn.freebsd.org/changeset/base/228501
Log:
After several suggestions from people, move eventtimers page from 7 to 4.
Added:
head/share/man/man4/eventtimers.4
- copied unchanged from r228500, head/share/man/man7/eventtimers.7
Deleted:
head/share/man/man7/eventtimers.7
Modified:
head/share/man/man4/Makefile
head/share/man/man4/atrtc.4
head/share/man/man4/attimer.4
head/share/man/man4/hpet.4
head/share/man/man7/Makefile
Modified: head/share/man/man4/Makefile
==============================================================================
--- head/share/man/man4/Makefile Wed Dec 14 14:55:19 2011
(r228500)
+++ head/share/man/man4/Makefile Wed Dec 14 15:19:40 2011
(r228501)
@@ -116,6 +116,7 @@ MAN= aac.4 \
epair.4 \
esp.4 \
et.4 \
+ eventtimers.4 \
exca.4 \
faith.4 \
fatm.4 \
Modified: head/share/man/man4/atrtc.4
==============================================================================
--- head/share/man/man4/atrtc.4 Wed Dec 14 14:55:19 2011 (r228500)
+++ head/share/man/man4/atrtc.4 Wed Dec 14 15:19:40 2011 (r228501)
@@ -53,4 +53,4 @@ Event timer provided by the driver is ir
.Sh SEE ALSO
.Xr attimer 4 ,
.Xr hpet 4 ,
-.Xr eventtimers 7
+.Xr eventtimers 4
Modified: head/share/man/man4/attimer.4
==============================================================================
--- head/share/man/man4/attimer.4 Wed Dec 14 14:55:19 2011
(r228500)
+++ head/share/man/man4/attimer.4 Wed Dec 14 15:19:40 2011
(r228501)
@@ -72,4 +72,4 @@ Event timer provided by the driver is ir
.Sh SEE ALSO
.Xr atrtc 4 ,
.Xr hpet 4 ,
-.Xr eventtimers 7
+.Xr eventtimers 4
Copied: head/share/man/man4/eventtimers.4 (from r228500,
head/share/man/man7/eventtimers.7)
==============================================================================
--- /dev/null 00:00:00 1970 (empty, because file is newly added)
+++ head/share/man/man4/eventtimers.4 Wed Dec 14 15:19:40 2011
(r228501, copy of r228500, head/share/man/man7/eventtimers.7)
@@ -0,0 +1,133 @@
+.\" Copyright (c) 2010 Alexander Motin <m...@freebsd.org>
+.\" 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.
+.\" 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 AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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.
+.\"
+.\" $FreeBSD$
+.\"
+.Dd September 15, 2010
+.Dt EVENTTIMERS 4
+.Os
+.Sh NAME
+.Nm eventtimers
+.Nd kernel event timers subsystem
+.Sh SYNOPSIS
+Kernel uses several types of time-related devices, such as: real time clocks,
+time counters and event timers.
+Real time clocks responsible for tracking real world time, mostly when system
+is down.
+Time counters are responsible for generation of monotonically increasing
+timestamps for precise uptime tracking purposes, when system is running.
+Event timers are responsible for generating interrupts at specified time or
+periodically, to run different time-based events.
+This page is about the last.
+.Sh DESCRIPTION
+Kernel uses time-based events for many different purposes: scheduling,
+statistics, time keeping, profiling and many other things, based on
+.Xr callout 9
+mechanism.
+These purposes now grouped into three main callbacks:
+.Bl -tag
+.It hardclock()
+.Xr callout 9
+and timekeeping events entry. Called with frequency defined by hz variable,
+usually 1000Hz.
+.It statclock()
+statistics and scheduler events entry. Called with frequency about 128Hz.
+.It profclock()
+profiler events entry. When enabled, called with frequency about 8KHz.
+.El
+Different platforms provide different kinds of timer hardware.
+The goal of the event timers subsystem is to provide unified way to control
+that hardware, and to use it, supplying kernel with all required time-based
+events.
+.Pp
+Each driver implementing event timers, registers them at the subsystem.
+It is possible to see the list of present event timers, like this, via
+.Va kern.eventtimer
+sysctl:
+.Bd -literal
+kern.eventtimer.choice: HPET(550) LAPIC(400) i8254(100) RTC(0)
+kern.eventtimer.et.LAPIC.flags: 15
+kern.eventtimer.et.LAPIC.frequency: 0
+kern.eventtimer.et.LAPIC.quality: 400
+kern.eventtimer.et.i8254.flags: 1
+kern.eventtimer.et.i8254.frequency: 1193182
+kern.eventtimer.et.i8254.quality: 100
+kern.eventtimer.et.RTC.flags: 17
+kern.eventtimer.et.RTC.frequency: 32768
+kern.eventtimer.et.RTC.quality: 0
+kern.eventtimer.et.HPET.flags: 7
+kern.eventtimer.et.HPET.frequency: 14318180
+kern.eventtimer.et.HPET.quality: 550
+.Ed
+, where:
+.Bl -tag
+.It Va kern.eventtimer.et. Ns Ar X Ns Va .flags
+bitmask, defining event timer capabilities:
+.Bl -tag -compact
+.It 1
+periodic mode supported,
+.It 2
+one-shot mode supported,
+.It 4
+timer is per-CPU,
+.It 8
+timer may stop when CPU goes to sleep state,
+.It 16
+timer supports only power-of-2 divisors.
+.El
+.It Va kern.eventtimer.et. Ns Ar X Ns Va .frequency
+timer base frequency,
+.It Va kern.eventtimer.et. Ns Ar X Ns Va .quality
+integral value, defining how good is this timer, comparing to others.
+.El
+.Pp
+Timers management code of the kernel chooses one timer from that list.
+Current choice can be read and affected via
+.Va kern.eventtimer.timer
+tunable/sysctl.
+Several other tunables/sysctls are affecting how exactly this timer is used:
+.Bl -tag
+.It Va kern.eventtimer.periodic
+allows to choose periodic and one-shot operation mode.
+In periodic mode, periodic interrupts from timer hardware are taken as the
+only source of time for time events.
+One-shot mode instead uses currently selected time counter to precisely
+schedule all needed events and programs event 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.
+.It Va 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
+1, 2 or 4, depending on configured HZ value.
+.It Va 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
+always generating.
+.El
+.Sh SEE ALSO
+.Xr attimer 4 ,
+.Xr atrtc 4 ,
+.Xr hpet 4
Modified: head/share/man/man4/hpet.4
==============================================================================
--- head/share/man/man4/hpet.4 Wed Dec 14 14:55:19 2011 (r228500)
+++ head/share/man/man4/hpet.4 Wed Dec 14 15:19:40 2011 (r228501)
@@ -96,7 +96,7 @@ of these comparators has own unsharable
.Xr acpi 4 ,
.Xr atrtc 4 ,
.Xr attimer 4 ,
-.Xr eventtimers 7
+.Xr eventtimers 4
.Sh HISTORY
The
.Nm
Modified: head/share/man/man7/Makefile
==============================================================================
--- head/share/man/man7/Makefile Wed Dec 14 14:55:19 2011
(r228500)
+++ head/share/man/man7/Makefile Wed Dec 14 15:19:40 2011
(r228501)
@@ -10,7 +10,6 @@ MAN= adding_user.7 \
c99.7 \
development.7 \
environ.7 \
- eventtimers.7 \
ffs.7 \
firewall.7 \
hier.7 \
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