Messages in this thread | | | From | Mel Gorman <> | Subject | [PATCH v5 0/2] Adjust NUMA imbalance for multiple LLCs | Date | Thu, 3 Feb 2022 14:46:50 +0000 |
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Changelog since V4 o Scale imbalance based on the top domain that prefers siblings o Keep allowed imbalance as 2 up to the point where LLCs can be overloaded
Changelog since V3 o Calculate imb_numa_nr for multiple SD_NUMA domains o Restore behaviour where communicating pairs remain on the same node
Commit 7d2b5dd0bcc4 ("sched/numa: Allow a floating imbalance between NUMA nodes") allowed an imbalance between NUMA nodes such that communicating tasks would not be pulled apart by the load balancer. This works fine when there is a 1:1 relationship between LLC and node but can be suboptimal for multiple LLCs if independent tasks prematurely use CPUs sharing cache.
The series addresses two problems -- inconsistent logic when allowing a NUMA imbalance and sub-optimal performance when there are many LLCs per NUMA node.
include/linux/sched/topology.h | 1 + kernel/sched/fair.c | 30 ++++++++++--------- kernel/sched/topology.c | 53 ++++++++++++++++++++++++++++++++++ 3 files changed, 71 insertions(+), 13 deletions(-)
-- 2.31.1
Mel Gorman (2): sched/fair: Improve consistency of allowed NUMA balance calculations sched/fair: Adjust the allowed NUMA imbalance when SD_NUMA spans multiple LLCs
include/linux/sched/topology.h | 1 + kernel/sched/fair.c | 30 ++++++++++--------- kernel/sched/topology.c | 53 ++++++++++++++++++++++++++++++++++ 3 files changed, 71 insertions(+), 13 deletions(-)
-- 2.31.1
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