linux-kernel - Re: [PATCH] sched/rt: Decrease number of calls of push_rt_task() in push_rt

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Date:	Tue, 5 Feb 2013 16:25:11 +0800
From:	Honghui Zhang <zhanghonghui@...wei.com>
To:	Kirill Tkhai <tkhai@...dex.ru>
CC:	Steven Rostedt <rostedt@...dmis.org>,
	<linux-kernel@...r.kernel.org>, Ingo Molnar <mingo@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	linux-rt-users <linux-rt-users@...r.kernel.org>
Subject: Re: [PATCH] sched/rt: Decrease number of calls of push_rt_task()
 in push_rt_tasks()

On 2013/2/5 15:22, Kirill Tkhai wrote:
>>
>> 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?
> 
> Yes. But this patch is about several pushable tasks on the same cpu.
> 
> Kirill
> 

Maybe I haven't make myself understood, but in that case, there will be a higher-priority
task in the runqueue of the pushing cpu, and a lower-priority task running in the last cpu
which could not be preempt by push_rt_task(),  I don't think it's acceptable.

Hans


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