diff options
| author | Ingo Molnar <mingo@redhat.com> | 2004-06-05 21:35:59 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2004-06-05 21:35:59 -0700 |
| commit | 996e0e6e91a37be0135d0f0ed2b6a1a44eff9894 (patch) | |
| tree | ca46e7d156b9a13519518a3b67a225a7a828c982 /kernel | |
| parent | ca24660ce7d870bcb06092a0880fab61463c4ea5 (diff) | |
[PATCH] sched: honor the "sync" wakeup bit
The scheduler changes had another thing missing: the appreciation of
sync wakeups. (I had this in one of the earlier sched-domains cleanup
patches before but it got lost in the shuffle.)
When a sync waker is waking, we should subtract its load from the
current load - it will schedule away for sure in the near future.
That's what the "sync" bit means.
This change is necessary because with the sched-domains balancer we have
a much more sensitive cpu-load estimator, and in this particular context
of try_to_wake_up() the sync waker's effect will always be part of the
load. Patch against your patch attached.
In my testing there's an additional increase in bw_pipe numbers on a
dual P2 box, it went from 110-120 MB/sec to 120-130 MB/sec.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index e632c92fd80f..df93027de475 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -762,6 +762,13 @@ static int try_to_wake_up(task_t * p, unsigned int state, int sync) load = source_load(cpu); this_load = target_load(this_cpu); + /* + * If sync wakeup then subtract the (maximum possible) effect of + * the currently running task from the load of the current CPU: + */ + if (sync) + this_load -= SCHED_LOAD_SCALE; + /* Don't pull the task off an idle CPU to a busy one */ if (load < SCHED_LOAD_SCALE && load + this_load > SCHED_LOAD_SCALE && this_load > load) |