Re: [PATCH] sched: fix env->src_cpu for active migration

From: Vincent Guittot
Date: Wed Feb 13 2013 - 09:28:27 EST

On 13 February 2013 15:08, Damien Wyart <damien.wyart@xxxxxxxxx> wrote:
> * Vincent Guittot <vincent.guittot@xxxxxxxxxx> [2013-02-13 13:08]:
>> Damien,
>> Regarding your sched_domain config and especially the flags field, you
>> should not be impacted by my patch because
>> - need_active_balance is the only new place that use env->src_cpu in
>> the load_balance function
>> - and your machine will never test the condition: "env->src_cpu >
>> env->dst_cpu" in need_active_balance because SD_ASYM_PACKING is not
>> set in your config
>> Have you tested the patch with others that could have modified the
>> load_balance function ?
> Yes, sorry, I should have been more precise in my initial report: your
> patch was not applied on top of vanilla 3.8-rc7, but a few other patches
> were also present. Seems the ones impacting load_balance are from
> Frederic's nohz work
> (;a=shortlog;h=refs/heads/3.8-rc6-nohz4)

thanks for the pointer. i'm going to have a look

> The patches from there modifying load_balance are:
> - "sched: Update nohz rq clock before searching busiest group on load balancing"
> - "sched: Update clock of nohz busiest rq before balancing"
> In this test, I did not use any kernel parameter related to this
> patchset (full_nohz, etc.).
> I am adding Frederic in Cc, not sure if the breakage is to be
> investigated on your side or his...

probably both

> Thanks for your explanations,
> --
> Damien
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