Re:[PATCH] sched/rt: Decrease number of calls of push_rt_task() in push_rt_tasks()

From: Kirill Tkhai
Date: Tue Feb 05 2013 - 05:27:14 EST




> 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.

Sure, I tried to prevent the fact of call of this function with locks of spinlocks etc. It may
be useful on system like 2 CPU, but it's not necessary for large systems. I'm not persist in this.

Kirill

>
> Hans
>
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