linux-kernel - Re: CPU scheduler question/problem

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Message-ID: <2cd4df870901260548s2376a01anae0db9707dcfa14@mail.gmail.com>
Date:	Mon, 26 Jan 2009 14:48:53 +0100
From:	Pawel Dziekonski <dzieko@...il.com>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...e.hu>
Subject: Re: CPU scheduler question/problem

2009/1/23 Peter Zijlstra <peterz@...radead.org>:

> The pipe workload you mentioned has would behave that way because pipes
> 'assume' a produces/consumer behaviour, and thus are more likely to
> place both tasks on the same cpu -- but will eventually pull them apart
> if they want to run concurrently.
>
> You might enable SCHED_DEBUG=y and try
>  echo NO_SYNC_WAKEUPS > /debug/sched_features

Hello,

that did the trick. Openssl now gets a whole core exclusively and gives full
performance.

Regarding quantum chemistry application -- it is also using pipes
for communication between worker processes. Now this app works OK.

Where I can read more on tuning sched_features for different workloads?

Also, is there a way get a list of available schedulers and how to switch
between them?

thanks, Pawel
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