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 85DE3CDB47E for ; Wed, 18 Oct 2023 20:45:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230050AbjJRUpM (ORCPT ); Wed, 18 Oct 2023 16:45:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51722 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229552AbjJRUpK (ORCPT ); Wed, 18 Oct 2023 16:45:10 -0400 Received: from smtpout.efficios.com (unknown [IPv6:2607:5300:203:b2ee::31e5]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A09BAA4 for ; Wed, 18 Oct 2023 13:45:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=efficios.com; s=smtpout1; t=1697661905; bh=WFYnTqSi8zmo4rKmus4j8G1ssP+zDU3csH61FA/nZ0M=; h=From:To:Cc:Subject:Date:From; b=n2DL5hkWXvJpUEhQ8GWDJBXeq8cgm/0mCkXlHVYB26KVrYtKLl0FeB9TdxrhxuEdo RQ/urvBw0i7lWu3p00sEGzV0M11NW4kqxfM/JongARbhqHOcTpmlX7KkLGVDUaapCB aENdejOgMo617IblNOhDQSprcbqS3KFnrZC3jvCCuej+Tr/pGGcg7gElrIKsFNYLlT 7n3LhCrZo8pc2PS2aHvOQC7+R7lEwMH+gsuzhI0pccflp41xNP56CUTQEW0IcXTMYf EI0qmUUmTG/I+gTmi5nEbKKHnED4qcOgTO/vS9FCTy/lltIQKTMeyJIkcrBnvX1yxK /KRgvdVgAN0cQ== Received: from thinkos.internal.efficios.com (192-222-143-198.qc.cable.ebox.net [192.222.143.198]) by smtpout.efficios.com (Postfix) with ESMTPSA id 4S9jXK0N5pz1Y97; Wed, 18 Oct 2023 16:45:05 -0400 (EDT) From: Mathieu Desnoyers To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, Mathieu Desnoyers , Ingo Molnar , Valentin Schneider , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Vincent Guittot , Juri Lelli , Swapnil Sapkal , Aaron Lu , Chen Yu , Tim Chen , K Prateek Nayak , "Gautham R . Shenoy" , x86@kernel.org Subject: [RFC PATCH 0/2] sched/fair migration reduction features Date: Wed, 18 Oct 2023 16:45:09 -0400 Message-Id: <20231018204511.1563390-1-mathieu.desnoyers@efficios.com> X-Mailer: git-send-email 2.39.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, This series introduces two new scheduler features: UTIL_FITS_CAPACITY and SELECT_BIAS_PREV. When used together, they achieve a 47% speedup of a hackbench workload which leaves some idle CPU time on a 192-core AMD EPYC. The main metrics which are significantly improved are: - cpu-migrations are reduced by 93%, - CPU utilization is increased by 22%. Feedback is welcome. I am especially interested to learn whether this series has positive or detrimental effects on performance of other workloads. Thanks, Mathieu Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Valentin Schneider Cc: Steven Rostedt Cc: Ben Segall Cc: Mel Gorman Cc: Daniel Bristot de Oliveira Cc: Vincent Guittot Cc: Juri Lelli Cc: Swapnil Sapkal Cc: Aaron Lu Cc: Chen Yu Cc: Tim Chen Cc: K Prateek Nayak Cc: Gautham R . Shenoy Cc: x86@kernel.org Mathieu Desnoyers (2): sched/fair: Introduce UTIL_FITS_CAPACITY feature sched/fair: Introduce SELECT_BIAS_PREV to reduce migrations kernel/sched/fair.c | 77 ++++++++++++++++++++++++++++++++++++----- kernel/sched/features.h | 12 +++++++ kernel/sched/sched.h | 5 +++ 3 files changed, 86 insertions(+), 8 deletions(-) -- 2.39.2