[lkml]   [1999]   [May]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: Overscheduling DOES happen with high web server load.
    On Fri, 7 May 1999, Greg Lindahl wrote:

    >Why is schedule called so frequently? The thundering herd. You get a
    >new connection, everyone wakes up, only one gets work, and everyone
    ^^^^^^^^^^^^^^^^^^ wrong
    >else goes back to sleep, each causing O(A) work to reschedule. M hits

    The reality until 2.2.7 is that everyone wakes up, need_resched of the
    current task is set to 1 so the rescheduled CPU will issue a schedule()
    very shortly, but nobody of the wakenup tasks gets rescheduled and
    schedule() become a nono. This is the main wastage of resources. I think
    it's just fixed in pre-2.2.8-4 though ;).

    Andrea Arcangeli

    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    Please read the FAQ at

     \ /
      Last update: 2005-03-22 13:51    [W:0.022 / U:1.492 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site