From: Rik van Riel <riel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
To: tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org
Subject: Re: [PATCH v4 RESEND 0/4] cpusets,isolcpus: exclude isolcpus from load balancing in cpusets
Date: Wed, 18 Mar 2015 12:13:36 -0400 [thread overview]
Message-ID: <5509A430.9040005@redhat.com> (raw)
In-Reply-To: <1425917530-1771-1-git-send-email-riel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
On 03/09/2015 12:12 PM, riel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org wrote:
> Ensure that cpus specified with the isolcpus= boot commandline
> option stay outside of the load balancing in the kernel scheduler.
>
> Operations like load balancing can introduce unwanted latencies,
> which is exactly what the isolcpus= commandline is there to prevent.
>
> Previously, simply creating a new cpuset, without even touching the
> cpuset.cpus field inside the new cpuset, would undo the effects of
> isolcpus=, by creating a scheduler domain spanning the whole system,
> and setting up load balancing inside that domain. The cpuset root
> cpuset.cpus file is read-only, so there was not even a way to undo
> that effect.
>
> This does not impact the majority of cpusets users, since isolcpus=
> is a fairly specialized feature used for realtime purposes.
>
> This version fixes the UP compilation issue, in the same way done
> for the other cpumasks.
Ping?
Tejun? Li?
WARNING: multiple messages have this Message-ID (diff)
From: Rik van Riel <riel@redhat.com>
To: tj@kernel.org
Cc: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
lizefan@huawei.com
Subject: Re: [PATCH v4 RESEND 0/4] cpusets,isolcpus: exclude isolcpus from load balancing in cpusets
Date: Wed, 18 Mar 2015 12:13:36 -0400 [thread overview]
Message-ID: <5509A430.9040005@redhat.com> (raw)
In-Reply-To: <1425917530-1771-1-git-send-email-riel@redhat.com>
On 03/09/2015 12:12 PM, riel@redhat.com wrote:
> Ensure that cpus specified with the isolcpus= boot commandline
> option stay outside of the load balancing in the kernel scheduler.
>
> Operations like load balancing can introduce unwanted latencies,
> which is exactly what the isolcpus= commandline is there to prevent.
>
> Previously, simply creating a new cpuset, without even touching the
> cpuset.cpus field inside the new cpuset, would undo the effects of
> isolcpus=, by creating a scheduler domain spanning the whole system,
> and setting up load balancing inside that domain. The cpuset root
> cpuset.cpus file is read-only, so there was not even a way to undo
> that effect.
>
> This does not impact the majority of cpusets users, since isolcpus=
> is a fairly specialized feature used for realtime purposes.
>
> This version fixes the UP compilation issue, in the same way done
> for the other cpumasks.
Ping?
Tejun? Li?
next prev parent reply other threads:[~2015-03-18 16:13 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-09 16:12 [PATCH v4 RESEND 0/4] cpusets,isolcpus: exclude isolcpus from load balancing in cpusets riel-H+wXaHxf7aLQT0dZR+AlfA
2015-03-09 16:12 ` riel
2015-03-09 16:12 ` [PATCH 1/4] sched,isolcpu: make cpu_isolated_map visible outside scheduler riel
2015-03-09 16:12 ` [PATCH 2/4] cpusets,isolcpus: exclude isolcpus from load balancing in cpusets riel
2015-03-09 16:12 ` [PATCH 3/4] cpusets,isolcpus: add file to show isolated cpus in cpuset riel
[not found] ` <1425917530-1771-4-git-send-email-riel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-03-18 16:47 ` Tejun Heo
2015-03-18 16:47 ` Tejun Heo
[not found] ` <20150318164745.GA21564-piEFEHQLUPpN0TnZuCh8vA@public.gmane.org>
2015-03-18 23:40 ` Rik van Riel
2015-03-18 23:40 ` Rik van Riel
2015-03-19 1:50 ` Zefan Li
2015-03-19 1:50 ` Zefan Li
[not found] ` <550A2B4C.5030705-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
2015-03-19 1:54 ` Rik van Riel
2015-03-19 1:54 ` Rik van Riel
[not found] ` <550A2C48.6080807-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-03-19 6:28 ` Zefan Li
2015-03-19 6:28 ` Zefan Li
2015-03-19 1:45 ` Rik van Riel
2015-03-19 1:45 ` Rik van Riel
[not found] ` <550A2A49.4060704-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-03-19 1:48 ` Tejun Heo
2015-03-19 1:48 ` Tejun Heo
2015-03-09 16:12 ` [PATCH 4/4] cpuset,isolcpus: document relationship between cpusets & isolcpus riel
[not found] ` <1425917530-1771-1-git-send-email-riel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2015-03-18 16:13 ` Rik van Riel [this message]
2015-03-18 16:13 ` [PATCH v4 RESEND 0/4] cpusets,isolcpus: exclude isolcpus from load balancing in cpusets Rik van Riel
2015-03-19 18:30 ` Tejun Heo
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