From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Zhao Chenhui <chenhui.zhao@freescale.com>
Cc: linux-rt-users@vger.kernel.org, linux-kernel@vger.kernel.org,
tglx@linutronix.de, leoli@freescale.com, scottwood@freescale.com,
Priyanka.Jain@freescale.com
Subject: Re: [PATCH][RFC] kernel/cpu: do not change the cpus_allowed of the current task when unplugging cpus
Date: Mon, 17 Jun 2013 13:49:46 +0200 [thread overview]
Message-ID: <51BEF7DA.700@linutronix.de> (raw)
In-Reply-To: <20130617104832.GA20410@localhost.localdomain>
On 06/17/2013 12:48 PM, Zhao Chenhui wrote:
> I don't think it is necessary to change the mask. migration_call() invoked by
> the cpu notify "CPU_DYING" will remove all running tasks from the dying cpu.
> Even if the current task is running on the dying cpu, it will be transfered
> to another online cpu.
I had here hiccups if the task was running on the CPU which should go
down.
> I guess that changing the mask benefits the latency of the system.
> Please correct me.
I don't get this. Lets say your system has CPUs 0-15 and you pin your
application to CPU0. After this application brings CPU15 down it is
allowed to run on CPUs 0-14. This is wrong and has been corrected. The
CPU down mechanism should not affected CPU mask of the application.
>
> -Chenhui
>
Sebastian
prev parent reply other threads:[~2013-06-17 11:49 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-16 10:17 [PATCH][RFC] kernel/cpu: do not change the cpus_allowed of the current task when unplugging cpus Zhao Chenhui
2013-06-07 9:05 ` Sebastian Andrzej Siewior
2013-06-09 9:59 ` Zhao Chenhui
2013-06-14 15:29 ` Sebastian Andrzej Siewior
2013-06-17 10:48 ` Zhao Chenhui
2013-06-17 11:49 ` Sebastian Andrzej Siewior [this message]
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