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    SubjectRe: [PATCH 3/6 v4] cpufreq: tolerate inexact values when collecting stats
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    On Saturday, November 17, 2012 03:50:48 PM Borislav Petkov wrote:
    > On Tue, Nov 13, 2012 at 02:13:38PM -0500, Mark Langsdorf wrote:
    > > Although cpufreq_driver has a flag field, no part of cpufreq_driver
    > > is directly passed to the cpufreq_stat code. Only cpufreq_policy
    > > is. It's cleaner to do passes of the while loop than to copy the
    > > cpufreq_driver.flag field into cpufreq_policy and then store it again
    > > in cpufreq_stats.
    >
    > That maybe so but this newly added loop which is only Calxeda-relevant
    > is called in cpufreq_stat_notifier_trans, which is the frequency change
    > notifier call, AFAICT.
    >
    > So each cpufreq driver will be paying that small and needless penalty
    > now for nothing and on each frequency change. Which adds to the
    > kernel-wide bloat and we absolutely don't want that.
    >
    > So you probably need to find a slick way of detecting calxeda hw
    > somewhere along the init path of cpufreq_stats_init and set a
    > hw-specific flag instead of adding that cost to each driver.

    Mark, I suppose you'd like me to take this series for v3.8, but the above
    comment from Boris has to be addressed for that.

    Thanks,
    Rafael


    --
    I speak only for myself.
    Rafael J. Wysocki, Intel Open Source Technology Center.


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