On 15/04/21 16:39, Rik van Riel wrote: > On Thu, 2021-04-15 at 18:58 +0100, Valentin Schneider wrote: >> Consider the following topology: >> >> Long story short, preempted misfit tasks are affected by task_hot(), >> while >> currently running misfit tasks are intentionally preempted by the >> stopper >> task to migrate them over to a higher-capacity CPU. >> >> Align detach_tasks() with the active-balance logic and let it pick a >> cache-hot misfit task when the destination CPU can provide a capacity >> uplift. >> >> Signed-off-by: Valentin Schneider <valentin.schnei...@arm.com> > > Reviewed-by: Rik van Riel <r...@surriel.com> >
Thanks! > > This patch looks good, but... > >> @@ -7672,6 +7698,15 @@ int can_migrate_task(struct task_struct *p, >> struct lb_env *env) >> if (tsk_cache_hot == -1) >> tsk_cache_hot = task_hot(p, env); >> >> + /* >> + * On a (sane) asymmetric CPU capacity system, the increase in >> compute >> + * capacity should offset any potential performance hit caused >> by a >> + * migration. >> + */ >> + if ((env->dst_grp_type == group_has_spare) && >> + !migrate_degrades_capacity(p, env)) >> + tsk_cache_hot = 0; > > ... I'm starting to wonder if we should not rename the > tsk_cache_hot variable to something else to make this > code more readable. Probably in another patch :) > I'd tend to agree, but naming is hard. "migration_harmful" ? > -- > All Rights Reversed.
