From: Josh Don <joshdon@google.com>
To: Peter Zijlstra <peterz@infradead.org>
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>,
Thomas Gleixner <tglx@linutronix.de>,
linux-kernel <linux-kernel@vger.kernel.org>,
mingo@kernel.org, torvalds@linux-foundation.org,
fweisbec@gmail.com, Kees Cook <keescook@chromium.org>,
Greg Kerr <kerrnel@google.com>, 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,
Paul Turner <pjt@google.com>,
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Patrick Bellasi <derkling@google.com>,
benbjiang@tencent.com,
Alexandre Chartre <alexandre.chartre@oracle.com>,
James.Bottomley@hansenpartnership.com, OWeisse@umich.edu,
Dhaval Giani <dhaval.giani@oracle.com>,
Junaid Shahid <junaids@google.com>,
Jesse Barnes <jsbarnes@google.com>,
"Hyser,Chris" <chris.hyser@oracle.com>,
Ben Segall <bsegall@google.com>, Hao Luo <haoluo@google.com>,
Tom Lendacky <thomas.lendacky@amd.com>
Subject: Re: [PATCH v10 2/5] sched: CGroup tagging interface for core scheduling
Date: Thu, 4 Feb 2021 19:45:39 -0800 [thread overview]
Message-ID: <CABk29NuS=7U4kgvGPf1=tVJxG3tiPqjr_H4ZhAFHaKSS4uqn2Q@mail.gmail.com> (raw)
In-Reply-To: <YBv8gBSKU1MdtXuW@hirez.programming.kicks-ass.net>
On Thu, Feb 4, 2021 at 5:54 AM Peter Zijlstra <peterz@infradead.org> wrote:
>
> On Fri, Jan 22, 2021 at 08:17:01PM -0500, Joel Fernandes (Google) wrote:
> > From: Peter Zijlstra <peterz@infradead.org>
>
> I'm thinking this is too much credit, I didn't write much of this.
>
> > Marks all tasks in a cgroup as matching for core-scheduling.
> >
> > A task will need to be moved into the core scheduler queue when the cgroup
> > it belongs to is tagged to run with core scheduling. Similarly the task
> > will need to be moved out of the core scheduler queue when the cgroup
> > is untagged.
> >
> > Also after we forked a task, its core scheduler queue's presence will
> > need to be updated according to its new cgroup's status.
> >
> > Use stop machine mechanism to update all tasks in a cgroup to prevent a
> > new task from sneaking into the cgroup, and missed out from the update
> > while we iterates through all the tasks in the cgroup. A more complicated
> > scheme could probably avoid the stop machine. Such scheme will also
> > need to resovle inconsistency between a task's cgroup core scheduling
> > tag and residency in core scheduler queue.
> >
> > We are opting for the simple stop machine mechanism for now that avoids
> > such complications.
> >
> > Core scheduler has extra overhead. Enable it only for core with
> > more than one SMT hardware threads.
>
> Very little actual words on the desired and implemented semantics of the
> interface, while the patch contains much non-obvious complication.
Ack to both, will fix in the next posting.
next prev parent reply other threads:[~2021-02-05 3:46 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-23 1:16 [PATCH v10 0/5] Core scheduling remaining patches Joel Fernandes (Google)
2021-01-23 1:17 ` [PATCH v10 1/5] sched: migration changes for core scheduling Joel Fernandes (Google)
2021-01-23 1:17 ` [PATCH v10 2/5] sched: CGroup tagging interface " Joel Fernandes (Google)
2021-02-03 16:51 ` Peter Zijlstra
2021-02-04 13:59 ` Peter Zijlstra
2021-02-05 16:42 ` Joel Fernandes
2021-02-04 13:54 ` Peter Zijlstra
2021-02-05 3:45 ` Josh Don [this message]
2021-02-04 13:57 ` Peter Zijlstra
2021-02-04 20:52 ` Chris Hyser
2021-02-05 10:43 ` Peter Zijlstra
2021-02-05 22:19 ` Chris Hyser
2021-02-04 14:01 ` Peter Zijlstra
2021-02-05 3:55 ` Josh Don
2021-02-04 14:35 ` Peter Zijlstra
2021-02-05 4:07 ` Josh Don
2021-02-04 14:52 ` Peter Zijlstra
2021-02-05 16:37 ` Joel Fernandes
2021-02-05 11:41 ` Peter Zijlstra
2021-02-05 11:52 ` Peter Zijlstra
2021-02-06 1:15 ` Josh Don
2021-02-05 12:00 ` Peter Zijlstra
2021-02-23 4:00 ` Chris Hyser
2021-02-23 9:05 ` Peter Zijlstra
2021-02-23 19:25 ` Chris Hyser
2021-02-24 5:15 ` Josh Don
2021-02-24 13:02 ` Chris Hyser
2021-02-24 13:52 ` chris hyser
2021-02-24 15:47 ` chris hyser
2021-02-26 20:07 ` Chris Hyser
2021-03-01 21:01 ` Josh Don
2021-01-23 1:17 ` [PATCH v10 3/5] kselftest: Add tests for core-sched interface Joel Fernandes (Google)
2021-01-23 1:17 ` [PATCH v10 4/5] Documentation: Add core scheduling documentation Joel Fernandes (Google)
2021-01-23 1:17 ` [PATCH v10 5/5] sched: Debug bits Joel Fernandes (Google)
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