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From: Ranjit Manomohan <>
Cc:, Mike Galbraith <>,
	Nikhil Rao <>, Salman Qazi <>,
	Dhaval Giani <>,
	Peter Zijlstra <>,
	Ingo Molnar <>,
	Thomas Gleixner <>,
	Venkatesh Pallipadi <>,
	Paul Turner <>
Subject: Re: [ANNOUNCE] Linsched for 2.6.35 released
Date: Tue, 15 Feb 2011 10:25:18 -0800	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On Tue, Feb 8, 2011 at 10:10 AM, Vaidyanathan Srinivasan
<> wrote:
> * Ranjit Manomohan <> [2010-11-15 17:52:05]:
>> On Mon, Oct 18, 2010 at 9:52 PM, Vaidyanathan Srinivasan
>> <> wrote:
>> > * Ranjit Manomohan <> [2010-10-12 10:29:54]:
>> >
> [snip]
>> > Can you help me figure out how to get to kstat_cpu() or per-cpu
>> > kernel_stat accounting/utilisation metrics within the simulation?
>> we don't use the kstat_cpu accounting in the simulation since it does
>> not really make sense in this environment.
>> We have a timer driven loop that advances time globally and kicks of
>> events scheduled to run at specified times on each CPU. The periodic
>> timer tick is one among these events. Since there is really no notion
>> of system vs user time in this scenario, the current code disables the
>> update_process_times routine. I am not sure how these times relate to
>> the task placement logic you are trying to verify. If you could let me
>> know how you plan to use these then I can try to accommodate that in
>> the simulation.
> The current setup lets us find how much time each task was run.
> I would like to use the kernel_stat information to understand 'which
> cpu' ran the task.  Basically we could place nr_tasks < nr_cpus and
> see them settle to the right CPUs within the sched domain topology.
> This can be verified by checking the CPU's utilisation or run time at
> the end of the simulation.  Like two tasks on the same socket of
> a dual-socket dual-core system should settle to one task per socket.
> The load balancer should be able to spread the tasks around slowly.
> The ability to create diverse topology within linsched is very
> useful to test these load balancer functions and corner cases.

Ok, I understand what you are looking for. There does not seem to be
anything in the kernel that I can reuse. I can add a Linsched specific
per cpu task counter to get the stats. I will try to send out an
update in a couple of days.

>> Sorry for the delay in response. My mail filters messed this up.
> I got your reply earlier. No problem with the delay.
> Do you have a new version to share?  Any new feature that you are planning?

Unfortunately we have fallen a little behind in terms of keeping
linsched up to date with mainline kernel releases. Hopefully we can
get an updated version out this summer. Our current plans are to
include a record/replay type of option to the simulation that will
allow us to optimize a particular workload. Please let me know if
there is anything else that you would like to see added.


> --Vaidy

      reply	other threads:[~2011-02-15 18:25 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-10-12 17:29 Ranjit Manomohan
2010-10-19  4:52 ` Vaidyanathan Srinivasan
2010-11-16  1:52   ` Ranjit Manomohan
2011-02-08 18:10     ` Vaidyanathan Srinivasan
2011-02-15 18:25       ` Ranjit Manomohan [this message]

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