From: Frederic Weisbecker <frederic@kernel.org>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: linux-kernel@vger.kernel.org,
Frederic Weisbecker <fweisbec@gmail.com>,
Chris Friesen <chris.friesen@windriver.com>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
Jim Somerville <Jim.Somerville@windriver.com>,
Christoph Lameter <cl@linux.com>
Subject: Re: [patch 0/4] affine kernel threads to nohz_full= cpumask (v4)
Date: Mon, 20 Apr 2020 18:02:46 +0200 [thread overview]
Message-ID: <20200420160245.GA10024@lenoir> (raw)
In-Reply-To: <20200401121018.104226700@redhat.com>
On Wed, Apr 01, 2020 at 09:10:18AM -0300, Marcelo Tosatti wrote:
> This is a kernel enhancement that configures the cpu affinity of kernel
> threads via kernel boot option nohz_full=.
>
> When this option is specified, the cpumask is immediately applied upon
> thread launch. This does not affect kernel threads that specify cpu
> and node.
>
> This allows CPU isolation (that is not allowing certain threads
> to execute on certain CPUs) without using the isolcpus=domain parameter,
> making it possible to enable load balancing on such CPUs
> during runtime (see kernel-parameters.txt).
>
> Note-1: this is based off on Wind River's patch at
> https://github.com/starlingx-staging/stx-integ/blob/master/kernel/kernel-std/centos/patches/affine-compute-kernel-threads.patch
>
> Difference being that this patch is limited to modifying
> kernel thread cpumask: Behaviour of other threads can
> be controlled via cgroups or sched_setaffinity.
>
> Note-2: Wind River's patch was based off Christoph Lameter's patch at
> https://lwn.net/Articles/565932/ with the only difference being
> the kernel parameter changed from kthread to kthread_cpus.
>
> v2: use isolcpus= subcommand (Thomas Gleixner)
>
> v3: s/MontaVista/Wind River/ on changelog (Chris Friesen)
> documentation updates (Chris Friesen)
> undeprecate isolcpus (Chris Friesen)
> general cleanups (Frederic Weisbecker)
> separate cpu_possible_mask kthread
> mask change (Frederic Weisbecker)
>
> v4: disable idle load balancing for nohz_full=
> use nohz_full= option for kthread isolation (Frederic Weisbecker)
>
Thanks for the patches. I'm applying them, I may add a few details
to the changelogs and stuff.
prev parent reply other threads:[~2020-04-20 16:02 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-01 12:10 [patch 0/4] affine kernel threads to nohz_full= cpumask (v4) Marcelo Tosatti
2020-04-01 12:10 ` [patch 1/4] kthread: switch to cpu_possible_mask Marcelo Tosatti
2020-04-01 12:10 ` [patch 2/4] isolation: set HK_FLAG_SCHED on nohz_full CPUs Marcelo Tosatti
2020-04-01 12:10 ` [patch 3/4] isolcpus: affine kernel threads to housekeeping cpus Marcelo Tosatti
2020-04-01 22:32 ` Randy Dunlap
2020-04-03 10:37 ` [patch 3/4 v2] " Marcelo Tosatti
2020-04-01 12:10 ` [patch 4/4] isolcpus: undeprecate on documentation Marcelo Tosatti
2020-04-20 16:02 ` Frederic Weisbecker [this message]
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