lkml.org 
[lkml]   [2005]   [Nov]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [RFC][PATCH] Runtime switching of the idle function [take 2]

    * Andrew Morton <akpm@osdl.org> wrote:

    > > The way to solve this was to set
    > > idle=poll. The original patch I sent was to allow the user to change to
    > > idle=poll dynamically. This way they could switch to the poll_idle and
    > > run there tests (requiring tsc not to drift) and then switch back to the
    > > default idle to save on electricity.
    >
    > Use gettimeofday()?
    >
    > If it's just for some sort of instrumentation, run NR_CPUS instances
    > of a niced-down busyloop, pin each one to a different CPU? That way
    > the idle function doesn't get called at all..

    idle=poll is also frequently done for performance reasons [it reduces
    idle wakeup latency by 10 usecs] - while it could be turned off if the
    system has been idle for some time. E.g. cpufreqd could sample idle time
    and turn on/off idle=poll. High-performance setups could enable it all
    the time.

    as long as it can be done with zero-cost, i dont see why Steven's patch
    wouldnt be a plus for us. It's a performance thing, and having runtime
    switches for seemless performance features cannot be bad.

    Ingo
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2005-11-29 07:47    [W:0.024 / U:29.648 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site