From: Peter Zijlstra <peterz@infradead.org>
To: changhuaixin <changhuaixin@linux.alibaba.com>
Cc: Benjamin Segall <bsegall@google.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
dtcccc@linux.alibaba.com, Juri Lelli <juri.lelli@redhat.com>,
khlebnikov@yandex-team.ru,
open list <linux-kernel@vger.kernel.org>,
Mel Gorman <mgorman@suse.de>, Ingo Molnar <mingo@redhat.com>,
Odin Ugedal <odin@uged.al>, Odin Ugedal <odin@ugedal.com>,
pauld@redhead.com, Paul Turner <pjt@google.com>,
Steven Rostedt <rostedt@goodmis.org>,
Shanpei Chen <shanpeic@linux.alibaba.com>,
Tejun Heo <tj@kernel.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
xiyou.wangcong@gmail.com
Subject: Re: [PATCH v5 1/3] sched/fair: Introduce the burstable CFS controller
Date: Tue, 25 May 2021 12:49:15 +0200 [thread overview]
Message-ID: <YKzWKxD+G4wTd2hf@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <C759D4F2-FA5F-4EB2-8441-C9ECD79AFD55@linux.alibaba.com>
On Mon, May 24, 2021 at 08:42:03PM +0800, changhuaixin wrote:
> >> --- a/kernel/sysctl.c
> >> +++ b/kernel/sysctl.c
> >> @@ -1816,6 +1816,15 @@ static struct ctl_table kern_table[] = {
> >> .proc_handler = proc_dointvec_minmax,
> >> .extra1 = SYSCTL_ONE,
> >> },
> >> + {
> >> + .procname = "sched_cfs_bw_burst_enabled",
> >> + .data = &sysctl_sched_cfs_bw_burst_enabled,
> >> + .maxlen = sizeof(unsigned int),
> >> + .mode = 0644,
> >> + .proc_handler = proc_dointvec_minmax,
> >> + .extra1 = SYSCTL_ZERO,
> >> + .extra2 = SYSCTL_ONE,
> >> + },
> >> #endif
> >> #if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL)
> >> {
> >
> > What's the purpose of this new sysctl? By default it is disabled because
> > burst==0, only if you set burst to some !0 value does this actually do
> > anything.
>
> Originally, this is designed to turn burst feature off when the system becomes unstable.
> Guess we can remove this as you have questioned it.
Is stability a concern? This is CFS after all, if we overload, we simply
share time as per usual.
If there is a real use-case for a global knob to limit/disable this I
don't object too much, but then please explicitly mention it.
next prev parent reply other threads:[~2021-05-25 10:50 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-20 12:34 [PATCH v5 0/3] sched/fair: Burstable CFS bandwidth controller Huaixin Chang
2021-05-20 12:34 ` [PATCH v5 1/3] sched/fair: Introduce the burstable CFS controller Huaixin Chang
2021-05-20 14:00 ` Odin Ugedal
2021-05-20 17:04 ` Tejun Heo
2021-05-21 9:09 ` changhuaixin
2021-05-21 9:38 ` Odin Ugedal
2021-05-21 12:38 ` changhuaixin
2021-05-21 14:00 ` Peter Zijlstra
2021-05-24 12:42 ` changhuaixin
2021-05-25 10:46 ` Peter Zijlstra
2021-05-31 6:59 ` luca abeni
2021-05-25 10:47 ` Peter Zijlstra
2021-05-25 21:25 ` Benjamin Segall
2021-05-25 10:49 ` Peter Zijlstra [this message]
2021-05-20 12:34 ` [PATCH v5 2/3] sched/fair: Add cfs bandwidth burst statistics Huaixin Chang
2021-05-20 14:11 ` Odin Ugedal
2021-05-21 12:42 ` changhuaixin
2021-05-21 14:05 ` Peter Zijlstra
2021-05-20 17:06 ` Tejun Heo
2021-05-21 14:01 ` Peter Zijlstra
2021-05-20 12:34 ` [PATCH v5 3/3] sched/fair: Add document for burstable CFS bandwidth Huaixin Chang
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