From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1C342C433FE for ; Tue, 8 Feb 2022 11:24:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233822AbiBHLXk (ORCPT ); Tue, 8 Feb 2022 06:23:40 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47352 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1355737AbiBHJxB (ORCPT ); Tue, 8 Feb 2022 04:53:01 -0500 X-Greylist: delayed 552 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Tue, 08 Feb 2022 01:52:59 PST Received: from outbound-smtp30.blacknight.com (outbound-smtp30.blacknight.com [81.17.249.61]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DA07BC03FEC0 for ; Tue, 8 Feb 2022 01:52:59 -0800 (PST) Received: from mail.blacknight.com (pemlinmail06.blacknight.ie [81.17.255.152]) by outbound-smtp30.blacknight.com (Postfix) with ESMTPS id 9BB69BAFE4 for ; Tue, 8 Feb 2022 09:43:45 +0000 (GMT) Received: (qmail 1402 invoked from network); 8 Feb 2022 09:43:45 -0000 Received: from unknown (HELO stampy.112glenside.lan) (mgorman@techsingularity.net@[84.203.17.223]) by 81.17.254.9 with ESMTPA; 8 Feb 2022 09:43:45 -0000 From: Mel Gorman To: Peter Zijlstra Cc: Ingo Molnar , Vincent Guittot , Valentin Schneider , Aubrey Li , Barry Song , Mike Galbraith , Srikar Dronamraju , Gautham Shenoy , K Prateek Nayak , LKML , Mel Gorman Subject: [PATCH v6 0/2] Adjust NUMA imbalance for multiple LLCs Date: Tue, 8 Feb 2022 09:43:32 +0000 Message-Id: <20220208094334.16379-1-mgorman@techsingularity.net> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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(-) -- 2.31.1