Re: [PATCH RESEND] sched: prefer an idle cpu vs an idle sibling for BALANCE_WAKE

[Srikar Dronamraju]

> At Facebook we have a pretty heavily multi-threaded application that is
> sensitive to latency.  We have been pulling forward the old SD_WAKE_IDLE code
> because it gives us a pretty significant performance gain (like 20%).  It turns
> out this is because there are cases where the scheduler puts our task on a busy
> CPU when there are idle CPU's in the system.  We verify this by reading the
> cpu_delay_req_avg_us from the scheduler netlink stuff.  With our crappy patch we
> get much lower numbers vs baseline.
>

Was this application run under cpu cgroup. Because we were seeing bursty
workloads exhibiting this behaviour esp when run under cpu cgroups.

http://mid.gmane.org/53A11A89.5000602@xxxxxxxxxxxxxxxxxx

-- 
Thansk and Regards
Srikar

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