Messages in this thread |  | | From | Byungchul Park <> | Subject | [PATCH v6 0/2] Make find_later_rq() choose a closer cpu in topology | Date | Mon, 7 Aug 2017 12:50:32 +0900 |
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When cpudl_find() returns any among free_cpus, the cpu might not be closer than others, considering sched domain. For example:
this_cpu: 15 free_cpus: 0, 1,..., 14 (== later_mask) best_cpu: 0
topology:
0 --+ +--+ 1 --+ | +-- ... --+ 2 --+ | | +--+ | 3 --+ |
... ...
12 --+ | +--+ | 13 --+ | | +-- ... -+ 14 --+ | +--+ 15 --+
In this case, it would be best to select 14 since it's a free cpu and closest to 15(this_cpu). However, currently the code select 0(best_cpu) even though that's just any among free_cpus. Fix it.
Change from v5 -. exclude two patches already picked up by peterz (sched/deadline: Make find_later_rq() choose a closer cpu in topology) (sched/deadline: Change return value of cpudl_find()) -. apply what peterz fixed for 'prefer sibling', into deadline and rt
Change from v4 -. remove a patch that might cause huge lock contention (by spin lock(&cpudl.lock) in a hot path of scheduler)
Change from v3 -. rename closest_cpu to best_cpu so that it align with rt -. protect referring cpudl.elements with cpudl.lock -. change return value of cpudl_find() to bool
Change from v2 -. add support for SD_PREFER_SIBLING
Change from v1 -. clean up the patch
Byungchul Park (2): sched/deadline: Add support for SD_PREFER_SIBLING on find_later_rq() sched/rt: Add support for SD_PREFER_SIBLING on find_lowest_rq()
kernel/sched/deadline.c | 46 +++++++++++++++++++++++++++++++++++++++++++--- kernel/sched/rt.c | 47 ++++++++++++++++++++++++++++++++++++++++++++--- 2 files changed, 87 insertions(+), 6 deletions(-)
-- 1.9.1
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