From: Honghui Zhang <zhanghonghui@huawei.com>
To: Kirill Tkhai <tkhai@yandex.ru>
Cc: Steven Rostedt <rostedt@goodmis.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
linux-rt-users <linux-rt-users@vger.kernel.org>
Subject: Re: [PATCH] sched/rt: Decrease number of calls of push_rt_task() in push_rt_tasks()
Date: Tue, 5 Feb 2013 11:37:14 +0800 [thread overview]
Message-ID: <51107E6A.3040006@huawei.com> (raw)
In-Reply-To: <313901359669474@web15h.yandex.ru>
On 2013/2/1 5:57, Kirill Tkhai wrote:
>
>
> 31.01.2013, 20:08, "Steven Rostedt" <rostedt@goodmis.org>:
>> On Mon, 2013-01-28 at 03:46 +0400, Kirill Tkhai wrote:
>>
>>> The patch aims to decrease the number of calls of push_rt_task()
>>> in push_rt_tasks().
>>>
>>> It's not necessary to push more than 'num_online_cpus() - 1' tasks.
>>> If just pushed task doesn't leave its new CPU during our local call
>>> of push_rt_tasks() than we won't push another task to the CPU.
>>> If it leave or change priority than it will pull new task by itself.
>>
>> I'm curious. Have you hit situations where this was an issue? Or was
>> this just discovered by code review?
>
> No, I did't hit this situation. It's impossible to hook every situation.
>
> Thanks for your explanation.
>
> Kirill
>
Suppose we have a large number of cpus(say 4096), with the last one running
a low-priority task on it. Is it possible with this patch we will never reach
the last cpu in case that previous cpu has complete the pulled task?
next prev parent reply other threads:[~2013-02-05 3:37 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-27 23:46 [PATCH] sched/rt: Decrease number of calls of push_rt_task() in push_rt_tasks() Kirill Tkhai
2013-01-31 16:08 ` Steven Rostedt
2013-01-31 21:57 ` Kirill Tkhai
2013-02-05 3:37 ` Honghui Zhang [this message]
-- strict thread matches above, loose matches on Subject: below --
2013-02-05 7:22 Kirill Tkhai
2013-02-05 8:25 ` [PATCH] " Honghui Zhang
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