Date: Mon, 13 Sep 2010 12:32:23 +0000 From: Alexander Best <arundel@freebsd.org> To: Alexander Motin <mav@FreeBSD.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r212541 - in head/sys: amd64/amd64 amd64/include dev/acpica i386/i386 i386/include kern mips/include mips/mips pc98/pc98 powerpc/aim powerpc/booke powerpc/include powerpc/powerpc sparc6... Message-ID: <20100913123223.GA99507@freebsd.org> In-Reply-To: <201009130725.o8D7PZX8073399@svn.freebsd.org> References: <201009130725.o8D7PZX8073399@svn.freebsd.org>
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On Mon Sep 13 10, Alexander Motin wrote: > [snip] > > 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. > > [snip] great! :) would it be possible to document these tunables in a new manual or add them to an existing one? sorry if i missed this and they are already documented somewhere. -- a13x
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