From: Peter Zijlstra <peterz@infradead.org>
To: Christoph Lameter <cl@gentwo.de>
Cc: Aaron Tomlin <atomlin@redhat.com>,
frederic@kernel.org, mtosatti@redhat.com, tglx@linutronix.de,
mingo@kernel.org, pauld@redhat.com, neelx@redhat.com,
oleksandr@natalenko.name, linux-kernel@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [RFC PATCH v3] tick/sched: Ensure quiet_vmstat() is called when the idle tick was stopped too
Date: Mon, 25 Apr 2022 15:27:00 +0200 [thread overview]
Message-ID: <20220425132700.GK2731@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <alpine.DEB.2.22.394.2204251406370.13839@gentwo.de>
On Mon, Apr 25, 2022 at 02:09:06PM +0200, Christoph Lameter wrote:
> On Mon, 25 Apr 2022, Aaron Tomlin wrote:
>
> > Yes, in the context of nohz, this patch should ensure it, if required, when
> > the idle tick is to be stopped.
>
> What I said was that it is generally useful. Even in the non NOHZ case.
>
> Folding the vmstat diffs *always* when entering idle prevents unnecessary
> wakeups and processing in the future and also provides more accurate
> counters for the VM allowing better decision to be made on reclaim.
I'm thinking you're going to find a ton of regressions if you try it
though; some workloads go idle *very* shortly, doing all this accounting
is going to be counter-productive.
next prev parent reply other threads:[~2022-04-25 13:27 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-22 19:36 Aaron Tomlin
2022-04-25 7:23 ` Christoph Lameter
2022-04-25 11:39 ` Aaron Tomlin
2022-04-25 12:09 ` Christoph Lameter
2022-04-25 13:27 ` Peter Zijlstra [this message]
2022-04-25 14:06 ` Christoph Lameter
2022-04-25 14:51 ` Aaron Tomlin
2022-04-25 14:57 ` Marcelo Tosatti
2022-04-25 14:17 ` Aaron Tomlin
2022-04-25 19:21 ` Marcelo Tosatti
2022-04-27 11:50 ` Aaron Tomlin
2022-04-27 14:40 ` Thomas Gleixner
2022-04-27 14:49 ` Aaron Tomlin
2022-04-28 18:10 ` Marcelo Tosatti
2022-05-04 9:32 ` Aaron Tomlin
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