diff options
| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2008-06-27 13:41:12 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-06-27 14:31:28 +0200 |
| commit | c9c294a630e28eec5f2865f028ecfc58d45c0a5a (patch) | |
| tree | 62fcfc395e98ff7a4ff6bee3364d0bb86024b171 /kernel/sched_fair.c | |
| parent | a7be37ac8e1565e00880531f4e2aff421a21c803 (diff) | |
| download | lwn-c9c294a630e28eec5f2865f028ecfc58d45c0a5a.tar.gz lwn-c9c294a630e28eec5f2865f028ecfc58d45c0a5a.zip | |
sched: fix calc_delta_asym()
calc_delta_asym() is supposed to do the same as calc_delta_fair() except
linearly shrink the result for negative nice processes - this causes them
to have a smaller preemption threshold so that they are more easily preempted.
The problem is that for task groups se->load.weight is the per cpu share of
the actual task group weight; take that into account.
Also provide a debug switch to disable the asymmetry (which I still don't
like - but it does greatly benefit some workloads)
This would explain the interactivity issues reported against group scheduling.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched_fair.c')
| -rw-r--r-- | kernel/sched_fair.c | 28 |
1 files changed, 27 insertions, 1 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 496500988ce5..2268e634812b 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -430,6 +430,29 @@ calc_delta_asym(unsigned long delta, struct sched_entity *se) for_each_sched_entity(se) { struct load_weight *se_lw = &se->load; +#ifdef CONFIG_FAIR_SCHED_GROUP + struct cfs_rq *cfs_rq = se->my_q; + struct task_group *tg = NULL + + if (cfs_rq) + tg = cfs_rq->tg; + + if (tg && tg->shares < NICE_0_LOAD) { + /* + * scale shares to what it would have been had + * tg->weight been NICE_0_LOAD: + * + * weight = 1024 * shares / tg->weight + */ + lw.weight *= se->load.weight; + lw.weight /= tg->shares; + + lw.inv_weight = 0; + + se_lw = &lw; + } else +#endif + if (se->load.weight < NICE_0_LOAD) se_lw = &lw; @@ -1154,7 +1177,10 @@ static unsigned long wakeup_gran(struct sched_entity *se) * More easily preempt - nice tasks, while not making it harder for * + nice tasks. */ - gran = calc_delta_asym(sysctl_sched_wakeup_granularity, se); + if (sched_feat(ASYM_GRAN)) + gran = calc_delta_asym(sysctl_sched_wakeup_granularity, se); + else + gran = calc_delta_fair(sysctl_sched_wakeup_granularity, se); return gran; } |