From: Peter Zijlstra <peterz@infradead.org>
To: "Li, Aubrey" <aubrey.li@linux.intel.com>
Cc: "Joel Fernandes (Google)" <joel@joelfernandes.org>,
Nishanth Aravamudan <naravamudan@digitalocean.com>,
Julien Desfossez <jdesfossez@digitalocean.com>,
Tim Chen <tim.c.chen@linux.intel.com>,
Vineeth Pillai <viremana@linux.microsoft.com>,
Aaron Lu <aaron.lwe@gmail.com>,
Aubrey Li <aubrey.intel@gmail.com>,
tglx@linutronix.de, linux-kernel@vger.kernel.org,
mingo@kernel.org, torvalds@linux-foundation.org,
fweisbec@gmail.com, keescook@chromium.org,
Phil Auld <pauld@redhat.com>,
Valentin Schneider <valentin.schneider@arm.com>,
Mel Gorman <mgorman@techsingularity.net>,
Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
Paolo Bonzini <pbonzini@redhat.com>,
vineeth@bitbyteword.org, Chen Yu <yu.c.chen@intel.com>,
Christian Brauner <christian.brauner@ubuntu.com>,
Agata Gruza <agata.gruza@intel.com>,
Antonio Gomez Iglesias <antonio.gomez.iglesias@intel.com>,
graf@amazon.com, konrad.wilk@oracle.com, dfaggioli@suse.com,
rostedt@goodmis.org, benbjiang@tencent.com,
Alexandre Chartre <alexandre.chartre@oracle.com>,
James.Bottomley@hansenpartnership.com, OWeisse@umich.edu,
Dhaval Giani <dhaval.giani@oracle.com>,
chris.hyser@oracle.com, Josh Don <joshdon@google.com>,
Hao Luo <haoluo@google.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Aubrey Li <aubrey.li@intel.com>
Subject: Re: [PATCH 1/6] sched: migration changes for core scheduling
Date: Mon, 22 Mar 2021 09:57:51 +0100 [thread overview]
Message-ID: <YFhcD/jz7kC8jaXa@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <af3f6ea6-2c71-233f-fc6b-af039b004923@linux.intel.com>
On Mon, Mar 22, 2021 at 04:12:17PM +0800, Li, Aubrey wrote:
> > But suppose there is an imbalance; then this cookie crud can forever
> > stall balance.
> >
> > Imagine this cpu running a while(1); with a uniqie cookie on, then it
> > will _never_ accept other tasks == BAD.
> >
>
> How about putting the following check in sched_core_cookie_match()?
>
> + /*
> + * Ignore cookie match if there is a big imbalance between the src rq
> + * and dst rq.
> + */
> + if ((src_rq->cfs.h_nr_running - rq->cfs.h_nr_running) > 1)
> + return true;
That's just tinkering... cookie matching should not also look at
imbalance of any kind.
> Do you have any suggestions before we drop it?
Yeah, how about you make it part of task_hot() ? Have task_hot() refuse
migration it the cookie doesn't match.
task_hot() is a hint and will get ignored when appropriate.
next prev parent reply other threads:[~2021-03-22 9:00 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-19 20:32 [PATCH 0/6] Core scheduling remaining patches Joel Fernandes (Google)
2021-03-19 20:32 ` [PATCH 1/6] sched: migration changes for core scheduling Joel Fernandes (Google)
2021-03-20 15:34 ` Peter Zijlstra
2021-03-21 13:34 ` Li, Aubrey
2021-03-22 7:48 ` Peter Zijlstra
2021-03-22 8:12 ` Li, Aubrey
2021-03-22 8:57 ` Peter Zijlstra [this message]
2021-03-22 12:31 ` Li, Aubrey
2021-03-22 12:56 ` Peter Zijlstra
2021-03-22 13:17 ` Li, Aubrey
2021-03-23 3:54 ` Li, Aubrey
2021-03-23 21:21 ` Josh Don
2021-03-19 20:32 ` [PATCH 2/6] sched: tagging interface " Joel Fernandes (Google)
2021-03-20 15:46 ` Peter Zijlstra
2021-03-22 17:57 ` Chris Hyser
2021-03-22 18:33 ` Peter Zijlstra
2021-03-22 18:35 ` Chris Hyser
2021-03-23 1:15 ` Josh Don
2021-03-19 20:32 ` [PATCH 3/6] sched: prctl() cookie manipulation " Joel Fernandes (Google)
2021-03-20 15:51 ` Peter Zijlstra
2021-03-19 20:32 ` [PATCH 4/6] kselftest: Add tests for core-sched interface Joel Fernandes (Google)
2021-03-19 20:32 ` [PATCH 5/6] Documentation: Add core scheduling documentation Joel Fernandes (Google)
2021-03-19 20:32 ` [PATCH 6/6] sched: Debug bits Joel Fernandes (Google)
2021-03-20 15:40 ` [PATCH 0/6] Core scheduling remaining patches Peter Zijlstra
2021-03-22 14:57 ` Joel Fernandes
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