Messages in this thread | | | Date | Fri, 28 Jun 2013 22:44:27 +0530 | From | Srikar Dronamraju <> | Subject | Re: [PATCH 5/8] sched: Favour moving tasks towards the preferred node |
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> > Yes, I understand that numa should have more priority over cache. > > But the schedstats will not be updated about whether the task was hot or > > cold. > > > > So lets say the task was cache hot but numa wants it to move, then we > > should certainly move it but we should update the schedstats to mention that we > > moved a cache hot task. > > > > Something akin to this. > > > > tsk_cache_hot = task_hot(p, env->src_rq->clock_task, env->sd); > > if (tsk_cache_hot) { > > if (migrate_improves_locality(p, env) || > > (env->sd->nr_balance_failed > env->sd->cache_nice_tries)) { > > #ifdef CONFIG_SCHEDSTATS > > schedstat_inc(env->sd, lb_hot_gained[env->idle]); > > schedstat_inc(p, se.statistics.nr_forced_migrations); > > #endif > > return 1; > > } > > schedstat_inc(p, se.statistics.nr_failed_migrations_hot); > > return 0; > > } > > return 1; > > > > Thanks. Is this acceptable? > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index b3848e0..c3a153e 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -4088,8 +4088,13 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env) > * 3) too many balance attempts have failed. > */ > > - if (migrate_improves_locality(p, env)) > + if (migrate_improves_locality(p, env)) { > +#ifdef CONFIG_SCHEDSTATS > + schedstat_inc(env->sd, lb_hot_gained[env->idle]); > + schedstat_inc(p, se.statistics.nr_forced_migrations); > +#endif > return 1; > + } >
In this case, we account even cache cold threads as _cache hot_ in schedstats.
We need the task_hot() call to determine if task is cache hot or not. So the migrate_improves_locality(), I think should be called within the tsk_cache_hot check.
Do you have issues with the above snippet that I posted earlier?
> tsk_cache_hot = task_hot(p, env->src_rq->clock_task, env->sd); > if (!tsk_cache_hot) > > -- > Mel Gorman > SUSE Labs >
-- Thanks and Regards Srikar Dronamraju
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