• Peter Zijlstra's avatar
    sched: Add new wakeup preemption mode: WAKEUP_RUNNING · ad4b78bb
    Peter Zijlstra authored
    Create a new wakeup preemption mode, preempt towards tasks that run
    shorter on avg. It sets next buddy to be sure we actually run the task
    we preempted for.
    
    Test results:
    
     root@twins:~# while :; do :; done &
     [1] 6537
     root@twins:~# while :; do :; done &
     [2] 6538
     root@twins:~# while :; do :; done &
     [3] 6539
     root@twins:~# while :; do :; done &
     [4] 6540
    
     root@twins:/home/peter# ./latt -c4 sleep 4
     Entries: 48 (clients=4)
    
     Averages:
     ------------------------------
            Max          4750 usec
            Avg           497 usec
            Stdev         737 usec
    
     root@twins:/home/peter# echo WAKEUP_RUNNING > /debug/sched_features
    
     root@twins:/home/peter# ./latt -c4 sleep 4
     Entries: 48 (clients=4)
    
     Averages:
     ------------------------------
            Max            14 usec
            Avg             5 usec
            Stdev           3 usec
    
    Disabled by default - needs more testing.
    Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
    Acked-by: default avatarMike Galbraith <efault@gmx.de>
    Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
    LKML-Reference: <new-submission>
    ad4b78bb
sched_debug.c 11.6 KB