Re: [PATCH] sched/fair: Do not decay new task load on first enqueue

[Wanpeng Li]

2016-10-10 18:01 GMT+08:00 Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>:
> On Sun, 09 Oct, at 11:39:27AM, Wanpeng Li wrote:
>>
>> The difference between this patch and Peterz's is your patch have a
>> delta since activate_task()->enqueue_task() does do update_rq_clock(),
>> so why don't have the delta will cause low cpu machines (4 or 8) to
>> regress against your another reply in this thread?
>
> Both my patch and Peter's patch cause issues with low cpu machines. In
> <20161004201105.GP16071@xxxxxxxxxxxxxxxxxxx> I said,
>
>  "This patch causes some low cpu machines (4 or 8) to regress. It turns
>   out they regress with my patch too."
>
> Have I misunderstood your question?

I compare this one https://marc.info/?l=linux-kernel&m=147446511924571
with Peterz's patch.

>
> I ran out of time to investigate this last week, though I did try all
> proposed patches, including Vincent's, and none of them produced wins
> across the board.
>
> I should get a bit further this week.
>
> Vincent, Dietmar, did you guys ever get around to submitting your PELT
> tracepoint patches? Getting some introspection into the scheduler's
> load balancing decisions would speed up this sort of research.