From: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
Paul Turner <pjt@google.com>, Venki Pallipadi <venki@google.com>,
Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>,
Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1] sched: fix nohz idle load balancer issues
Date: Tue, 27 Sep 2011 16:01:06 +0530 [thread overview]
Message-ID: <20110927103106.GD4357@linux.vnet.ibm.com> (raw)
In-Reply-To: <20110927063222.GB18519@elte.hu>
* Ingo Molnar <mingo@elte.hu> [2011-09-27 08:32:24]:
> What are the tasks doing which are running - are they plain burning
> CPU time? If the tasks do something more complex, do you also have a
> measure of how much work gets done by the workload, per second?
They are simple cpu hogs at this time.
> Percentual changes in that metric would be nice to include in an
> additional column - that way we can see that it's not only idle
> that has gone down, but workload performance has gone up too.
Ok, good point.
> In fact even if there was only a CPU burning loop in the workload it
> would be nice to make that somewhat more sophisticated by letting it
> process some larger array that has a cache footprint. This mimics
> real workloads that don't just spin burning CPU time but do real data
> processing.
>
> For any non-trivial workload it's possible to reduce idle time
> without much increase in work done and in fact it's possible to
> decrease idle time *and* work done - so we need to see more clearly
> here and make sure it's all an improvement.
Ok - I will run a cpu intensive benchmark and get some numbers on
how benchmark score varies with the patch applied. I can pick a simple
matrix multiplication type benchmark, unless you have other suggestions!
- vatsa
next prev parent reply other threads:[~2011-09-27 10:31 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-26 11:50 [PATCH v1] sched: fix nohz idle load balancer issues Srivatsa Vaddagiri
2011-09-26 12:01 ` Srivatsa Vaddagiri
2011-09-27 6:32 ` Ingo Molnar
2011-09-27 10:31 ` Srivatsa Vaddagiri [this message]
2011-09-27 13:39 ` Ingo Molnar
2011-09-27 19:53 ` Venki Pallipadi
2011-09-27 23:49 ` Suresh Siddha
2011-09-28 4:15 ` Srivatsa Vaddagiri
2011-09-29 0:47 ` Suresh Siddha
2011-09-29 2:13 ` Srivatsa Vaddagiri
2011-09-29 8:15 ` Peter Zijlstra
2011-09-29 17:13 ` Suresh Siddha
2011-09-28 4:34 ` Srivatsa Vaddagiri
2011-09-28 4:39 ` Srivatsa Vaddagiri
2011-09-28 5:06 ` Srivatsa Vaddagiri
2011-09-28 14:17 ` Srivatsa Vaddagiri
2011-09-28 14:27 ` Srivatsa Vaddagiri
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