Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753081Ab2H1UP3 (ORCPT ); Tue, 28 Aug 2012 16:15:29 -0400 Received: from mail-pz0-f46.google.com ([209.85.210.46]:40773 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752083Ab2H1UP2 (ORCPT ); Tue, 28 Aug 2012 16:15:28 -0400 MIME-Version: 1.0 In-Reply-To: <87mx1phzf1.fsf@sejong.aot.lge.com> References: <1345442050.25011.38.camel@marge.simpson.net> <87mx1phzf1.fsf@sejong.aot.lge.com> Date: Tue, 28 Aug 2012 13:15:27 -0700 Message-ID: Subject: Re: changing timeslice in linux From: Xin Tong To: Namhyung Kim Cc: Mike Galbraith , linux-kernel Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2084 Lines: 56 i changed the TIMESLICE defined in the sched.c 109 /* 110 * These are the 'tuning knobs' of the scheduler: 111 * 112 * default timeslice is 100 msecs (used only for SCHED_RR tasks). 113 * Timeslices get refilled after they expire. 114 */ 115 #define DEF_TIMESLICE (20 * HZ / 1000) I compiled and installed the modified kernel, but when i looked at the , i get a different number root@elm:~# cat /proc/sys/kernel/sched_rt_period_us 1000000 Xin On Mon, Aug 20, 2012 at 5:16 PM, Namhyung Kim wrote: > On Mon, 20 Aug 2012 07:51:52 -0700, Xin Tong wrote: >> On Sun, Aug 19, 2012 at 10:54 PM, Mike Galbraith wrote: >>> On Sun, 2012-08-19 at 11:58 -0700, Xin Tong wrote: >>>> I have 2 questions about linux 2.6 x86_64 scheduler. >>>> >>>> 1. is the default scheduling algorithm SCHED_NORMAL in linux ? >>> >>> Yes. >> Is there any document describing what the sched_normal is ? it is more >> difficult than SCHED_RR to infer its meaning just based on its name ? >>> >>>> 2. how do i change the time slice in linux source code ? >>> >>> You shouldn't need to. You can tune "slice" by adjusting >>> sched_latency_ns and sched_min_granularity_ns, but note that "slice" is >>> not a fixed quantum. Also note that CFS preemption decisions are based >>> upon instantaneous state. A task may have received a full (variable) >>> "slice" of CPU time, but preemption will be triggered only if a more >>> deserving task is available, so a "slice" is not the "max uninterrupted >>> CPU time" that you may expect it to be.. but it is somewhat similar. >>> >>> -Mike >>> >> This can be done without recompiling and reinstalling the kernel ? >> maybe one simply needs to write to a device file under /dev ? > > You can find those files under /proc/sys/kernel/. > > Thanks, > Namhyung -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/