On Wed, Sep 13, 2017 at 12:24:30PM +0200, Uladzislau Rezki (Sony) wrote: > From: Uladzislau Rezki <ure...@gmail.com> > > As a first step this patch makes cfs_tasks list as MRU one. > It means, that when a next task is picked to run on physical > CPU it is moved to the front of the list. > > Therefore, the cfs_tasks list is more or less sorted (except > woken tasks) starting from recently given CPU time tasks toward > tasks with max wait time in a run-queue, i.e. MRU list. > > Second, as part of the load balance operation, this approach > starts detach_tasks()/detach_one_task() from the tail of the > queue instead of the head, giving some advantages: > > - tends to pick a task with highest wait time; > - tasks located in the tail are less likely cache-hot, > therefore the can_migrate_task() decision is higher. > > hackbench illustrates slightly better performance. For example > doing 1000 samples and 40 groups on i5-3320M CPU, it shows below > figures: > > default: 0.657 avg > patched: 0.646 avg > > Signed-off-by: Uladzislau Rezki (Sony) <ure...@gmail.com>
Thanks!
