lkml.org 
[lkml]   [2007]   [Mar]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: SMP performance degradation with sysbench
    On Tue, Mar 13, 2007 at 09:06:14PM +1100, Nick Piggin wrote:
    > Well ignoring the HT issue, I was seeing lots of idle time simply
    > because userspace could not keep up enough load to the scheduler.
    > There simply were fewer runnable tasks than CPU cores.

    When you said idle I thought idle and not waiting for I/O. Waiting for
    I/O would be hardly a kernel issue ;). If they're not waiting for I/O
    and they're not scheduling in userland with nanosleep/pause, the cpu
    shouldn't go idle. Even if they're calling sched_yield in a loop the
    cpu should account for zero idle time as far as I can tell.
    -
    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: 2007-03-13 11:35    [W:0.018 / U:0.108 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site