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

From: Wanpeng Li
Date: Mon Oct 10 2016 - 06:15:29 EST

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
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.