Re: cpu_exclusive feature of cpuset broken?

From: Srivatsa Vaddagiri
Date: Thu Mar 16 2006 - 11:59:12 EST

On Thu, Mar 16, 2006 at 08:38:36AM -0800, Paul Jackson wrote:
> While you created a subcpuset 'a', you changed the
> cpus and cpu_exclusive in the root cpuset. This
> changed -all- tasks to only be allowed to run on
> cpu 7.

oops sorry ..i did mean to say that i was trying to change
cpu-exclusive flag of a (and not the root cpuset).

> I'd guess you have some kernel thread or such that
> really, really wants to run on some other cpu.
> When I read you transcript, I expected it to say:
> # mkdir /dev/cpuset
> # mount -t cpuset cpuset /dev/cpuset # s/none/cpuset/ - clearer
> # cd /dev/cpuset
> # mkdir a
> # cd a # the missing step

Yes are right. I did run 'cd a' and then ran the below commands.

> # /bin/echo 7 > cpus
> # /bin/echo 1 > cpu_exclusive

> When I do your commands (without the 'cd a'), I don't
> see any problem or hang on my Altix test box. But that
> probably just means I am not critically depending at that
> moment on some kernel thread running on any particular cpu.

Did you try with the 'cd a' (in other words turn on exclusive
property of cpuset 'a')?

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