From: Peter Zijlstra <peterz@infradead.org>
To: Mel Gorman <mgorman@techsingularity.net>
Cc: Ingo Molnar <mingo@kernel.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
Valentin Schneider <valentin.schneider@arm.com>,
Aubrey Li <aubrey.li@linux.intel.com>,
Barry Song <song.bao.hua@hisilicon.com>,
Mike Galbraith <efault@gmx.de>,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
Gautham Shenoy <gautham.shenoy@amd.com>,
K Prateek Nayak <kprateek.nayak@amd.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v6 0/2] Adjust NUMA imbalance for multiple LLCs
Date: Wed, 9 Feb 2022 10:38:28 +0100 [thread overview]
Message-ID: <20220209093828.GL23216@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <20220208094334.16379-1-mgorman@techsingularity.net>
On Tue, Feb 08, 2022 at 09:43:32AM +0000, Mel Gorman wrote:
> Changelog sinve v5
> o Fix off-by-one error
>
> 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(-)
Thanks!
prev parent reply other threads:[~2022-02-09 9:41 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-08 9:43 [PATCH v6 0/2] Adjust NUMA imbalance for multiple LLCs Mel Gorman
2022-02-08 9:43 ` [PATCH 1/2] sched/fair: Improve consistency of allowed NUMA balance calculations Mel Gorman
2022-02-08 15:06 ` Gautham R. Shenoy
2022-02-14 9:48 ` Vincent Guittot
2022-02-14 10:26 ` Srikar Dronamraju
2022-02-14 10:30 ` [tip: sched/core] " tip-bot2 for Mel Gorman
2022-02-08 9:43 ` [PATCH 2/2] sched/fair: Adjust the allowed NUMA imbalance when SD_NUMA spans multiple LLCs Mel Gorman
2022-02-08 16:19 ` Gautham R. Shenoy
2022-02-09 5:10 ` K Prateek Nayak
2022-02-09 10:33 ` Mel Gorman
2022-02-11 19:02 ` Jirka Hladky
2022-02-14 10:27 ` Srikar Dronamraju
2022-02-14 10:30 ` [tip: sched/core] " tip-bot2 for Mel Gorman
2022-02-14 11:03 ` [PATCH 2/2] " Vincent Guittot
2022-02-09 9:38 ` Peter Zijlstra [this message]
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