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 X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CD1BEC47082 for ; Tue, 8 Jun 2021 19:51:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A8EE661375 for ; Tue, 8 Jun 2021 19:51:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234252AbhFHTx0 (ORCPT ); Tue, 8 Jun 2021 15:53:26 -0400 Received: from mail2-relais-roc.national.inria.fr ([192.134.164.83]:55892 "EHLO mail2-relais-roc.national.inria.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234218AbhFHTxZ (ORCPT ); Tue, 8 Jun 2021 15:53:25 -0400 IronPort-HdrOrdr: =?us-ascii?q?A9a23=3A7IOHRKA5dz/lkGDlHemd55DYdb4zR+YMi2TD?= =?us-ascii?q?GXoBMCC9Ffbo9fxG/c5rtiMc5wxhPk3I9erhBED/ewK6yXcF2/h1AV7KZmCP0w?= =?us-ascii?q?qVxelZg7cKqAeQfxEWmNQtrZuIsJISNDQzNzJHZArBjDVQa+xQu+VvOZrGudvj?= X-IronPort-AV: E=Sophos;i="5.83,259,1616454000"; d="scan'208";a="512448444" Received: from 173.121.68.85.rev.sfr.net (HELO hadrien) ([85.68.121.173]) by mail2-relais-roc.national.inria.fr with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 08 Jun 2021 21:51:30 +0200 Date: Tue, 8 Jun 2021 21:51:30 +0200 (CEST) From: Julia Lawall X-X-Sender: jll@hadrien To: Ingo Molnar , Peter Zijlstra , Vincent Guittot , Dietmar Eggemann , Mel Gorman , linux-kernel@vger.kernel.org Subject: find_new_ilb Message-ID: User-Agent: Alpine 2.22 (DEB 394 2020-01-19) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Starting from the following commit: commit 45da7a2b0af8fa29dff2e6ba8926322068350fce Author: Peter Zijlstra Date: Tue Aug 18 10:48:17 2020 +0200 sched/fair: Exclude the current CPU from find_new_ilb() up through Linux 5.12, I observed that often when most of the machine was idle, there could be many (thousands) of sched_wake_idle_without_ipi events, typically between cores 0 and 1. I don't see this any more in Linux v5.13-rc1. I looked through the patches to fair.c and core.c subsequent to v5.12, and I didn't see anything that explicitly addresses this issue. Before I plunge into another set of rounds of bisecting, I wonder if anyone knows whether and how this problem was resolved? thanks, julia