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    SubjectRe: [PATCH] tracing, perf: add more power related events
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    Hi Jean,

    Summary at the beginning if people stop reading on the details
    below...:
    Nice work!
    You have my vote to get this merged.
    I think it's up to Ingo to push it.


    Ehh, the patch you send misses the sleep state tracing event
    which shows up on the link you point to below, but this can
    be sent as a separate patch as well:

    --- a/include/trace/events/power.h
    +++ b/include/trace/events/power.h
    @@ -13,9 +13,14 @@ enum {
    POWER_NONE = 0,
    POWER_CSTATE = 1,
    POWER_PSTATE = 2,
    + POWER_SSTATE = 3,
    };
    #endif

    On Friday 03 September 2010 19:00:32 Jean Pihet wrote:
    > Hi,
    >
    > I would like to get some feedback on the code or on the new events
    > definition, cf. proposed patch in this thread.
    >
    > The idea is to provide new events for power management, as indicated
    > at http://www.omappedia.com/wiki/Power_Management_Debug_and_Profiling
    now I get why I got CC'ed..., the cpufreq perf events work on ARM since
    git commit 6f4f2723d08534fd4e407e1ef8500b0f4d12c30c
    right?

    I can't judge the ARM specific things in detail, let me try to compare
    this with X86 as your concern is that your patch is touching a generic
    interface:

    Power Domain events:
    I doubt that power domains or something similar shows up on x86
    any time soon. So if this fits for ARM, why not adding it...

    Clock Events:
    Hm, this could fit with throttling states.
    But it's not worth adding for X86 (might get controlled by HW on
    critical thermal conditions and with the p4_clockmod driver which should
    not exist, this would show up as P-states).
    But in theory those could get re-used on X86.
    New POWER_SSTATE event:
    The sleep state tracing might not be that interesting for X86 where you
    realize when you sleep, but sounds reasonable for a mobile phone where
    there could exist sleeping states in which you could still get phone
    calls or similar?
    If we had sleep states for x86 servers one could track how often a data
    center workload manager has put backup machines to sleep. Will not
    happen any time soon unless someone builds a laptop server farm, but
    yes, sounds like a useful thing depending on architecture and what you
    want to do with your machine...

    > As soon as the new events are defined -i.e. accepted in the mainline
    > code- the tracepoints will be added for ARM/OMAP.
    >
    > Any idea, remark or feedback welcome!
    Again: nice work.

    Thomas


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