From: Chris Friesen <chris.friesen@windriver.com>
To: Thomas Gleixner <tglx@linutronix.de>,
Marcelo Tosatti <mtosatti@redhat.com>,
linux-kernel@vger.kernel.org
Cc: Christoph Lameter <cl@linux.com>, Vu Tran <vu.tran@windriver.com>,
Jim Somerville <Jim.Somerville@windriver.com>,
Andrew Morton <akpm@linux-foundation.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH] affine kernel threads to specified cpumask
Date: Mon, 23 Mar 2020 11:02:37 -0600 [thread overview]
Message-ID: <af285c22-2a3f-5aa6-3fdb-27fba73389bd@windriver.com> (raw)
In-Reply-To: <87k13boxcn.fsf@nanos.tec.linutronix.de>
On 3/23/2020 10:22 AM, Thomas Gleixner wrote:
> Marcelo,
> Marcelo Tosatti <mtosatti@redhat.com> writes:
>
> the subject lacks a prefix and the CC list a few people.
>
>> This is a kernel enhancement to configure the cpu affinity of kernel
>> threads via kernel boot option kthread_cpus=<cpulist>.
>>
>> With kthread_cpus 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= parameter,
>> making it possible to enable load balancing on such CPUs
>> during runtime.
>
> I'm surely missing some background information, but that sentence does
> not make any sense to me.
>
> Thanks,
>
> tglx
>
The idea is to affine general kernel threads to specific "housekeeping"
CPUs, while still allowing load balancing of tasks.
The isolcpus= boot parameter would prevent kernel threads from running
on the isolated CPUs, but it disables load balancing on the isolated CPUs.
Chris
next prev parent reply other threads:[~2020-03-23 17:02 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-23 13:54 [PATCH] affine kernel threads to specified cpumask Marcelo Tosatti
2020-03-23 15:29 ` Chris Friesen
2020-03-24 15:07 ` Marcelo Tosatti
2020-03-23 16:22 ` Thomas Gleixner
2020-03-23 17:02 ` Chris Friesen [this message]
2020-03-23 20:31 ` Thomas Gleixner
2020-03-24 11:38 ` Marcelo Tosatti
2020-03-24 15:20 ` [PATCH v2] isolcpus: " Marcelo Tosatti
2020-03-24 15:56 ` Chris Friesen
2020-03-24 16:50 ` Marcelo Tosatti
2020-03-25 0:30 ` Frederic Weisbecker
2020-03-25 11:47 ` Marcelo Tosatti
2020-03-26 16:20 ` Frederic Weisbecker
2020-03-26 16:52 ` Frederic Weisbecker
2020-03-27 12:07 ` Marcelo Tosatti
2020-03-25 18:05 ` David Laight
2020-03-26 11:28 ` Marcelo Tosatti
2020-03-26 16:22 ` Frederic Weisbecker
2020-03-26 16:32 ` Chris Friesen
2020-03-26 16:51 ` Frederic Weisbecker
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