Re: Ok to change cpuset flags for sched domains? (was [PATCH 1/3] CPUMETER ...)

From: Dinakar Guniguntala (dino_at_in.ibm.com)
Date: 10/03/05

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    Date:	Mon, 3 Oct 2005 19:30:32 +0530
To: Paul Jackson <pj@sgi.com>

    I have been wanting to follow the cpumeter discussion more closely,
    but currently am tied up. I hope to have more time towards the end of
    this week.

    I had a few queries below, though

    On Sun, Oct 02, 2005 at 12:01:59AM -0700, Paul Jackson wrote:
    > Dinikar,
    >
    > How much grief will it cause you if I make the following incompatible
    > change to the special boolean files in each cpuset directory?
    >
    > I think I goofed in encouraging you to overload "cpu_exclusive"
    > with defining dynamic scheduler domains. I should have asked for a
    > separate flag to be added for that, say "sched_domain", which would
    > require "cpu_exclusive=1" as a precondition. Other attributes that
    > require cpu_exclusive or mem_exclusive are showing up, and it makes
    > more sense for each of them to get their own boolean, and leave the
    > "*_exclusive" flags to specify just the exclusive (no overlap with
    > sibling) attribute.

    One of the reasons for overloading the cpu_exclusive flag was to
    ensure that the rebalance code does not try to pull tasks unnecessarily

    With the scheme that you are proposing that is a possibility if
    you turn on the cpu_exclusive and meter_cpu for example and not
    turn on sched_domain. Is there a reason why we would want to have
    exclusive cpusets not attached to sched domains at all?

    I am not entirely convinced that we can compare sched_domains and
    meter_cpus.

    However I am still open if there is a convincing reason to have
    exclusive cpusets that dont form sched domains.

            -Dinakar
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