Messages in this thread Patch in this message | | | Date | Wed, 10 May 2023 13:49:13 -0000 | From | "tip-bot2 for Ricardo Neri" <> | Subject | [tip: sched/core] sched/fair: Keep a fully_busy SMT sched group as busiest |
| |
The following commit has been merged into the sched/core branch of tip:
Commit-ID: 5fd6d7f43958cb62da105c8413eac3e78480f09a Gitweb: https://git.kernel.org/tip/5fd6d7f43958cb62da105c8413eac3e78480f09a Author: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> AuthorDate: Thu, 06 Apr 2023 13:31:41 -07:00 Committer: Peter Zijlstra <peterz@infradead.org> CommitterDate: Mon, 08 May 2023 10:58:35 +02:00
sched/fair: Keep a fully_busy SMT sched group as busiest
When comparing two fully_busy scheduling groups, keep the current busiest group if it represents an SMT core. Tasks in such scheduling group share CPU resources and need more help than tasks in a non-SMT fully_busy group.
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Zhang Rui <rui.zhang@intel.com> Link: https://lore.kernel.org/r/20230406203148.19182-6-ricardo.neri-calderon@linux.intel.com --- kernel/sched/fair.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 85ce249..4a9f040 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -9619,10 +9619,22 @@ static bool update_sd_pick_busiest(struct lb_env *env, * contention when accessing shared HW resources. * * XXX for now avg_load is not computed and always 0 so we - * select the 1st one. + * select the 1st one, except if @sg is composed of SMT + * siblings. */ - if (sgs->avg_load <= busiest->avg_load) + + if (sgs->avg_load < busiest->avg_load) return false; + + if (sgs->avg_load == busiest->avg_load) { + /* + * SMT sched groups need more help than non-SMT groups. + * If @sg happens to also be SMT, either choice is good. + */ + if (sds->busiest->flags & SD_SHARE_CPUCAPACITY) + return false; + } + break; case group_has_spare:
| |