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=-18.2 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_IN_DEF_DKIM_WL autolearn=ham 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 E1856C4338F for ; Tue, 24 Aug 2021 17:49:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C5BD3613BD for ; Tue, 24 Aug 2021 17:49:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240421AbhHXRuY (ORCPT ); Tue, 24 Aug 2021 13:50:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39286 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234995AbhHXRuR (ORCPT ); Tue, 24 Aug 2021 13:50:17 -0400 Received: from mail-yb1-xb2a.google.com (mail-yb1-xb2a.google.com [IPv6:2607:f8b0:4864:20::b2a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3B9B9C04C39E for ; Tue, 24 Aug 2021 10:12:26 -0700 (PDT) Received: by mail-yb1-xb2a.google.com with SMTP id z128so42392307ybc.10 for ; Tue, 24 Aug 2021 10:12:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=PfOHx/yYiVRDFcplLpIShH9j4DkSNtuEs48LotWh3gY=; b=qR+Cx3gYe5B4T+OEfcLxI2qUcoOx0R40mL2hb9r9JU0eHhjgV+aNoNXfTcvpE2giLM iGr+K/xv5QqnR+ic+DUGfM8sHlAoDHqadQRe4mMN/wC7kZrUMXlmhEbGH34Zp17S+PYG 3VEcoSOi63Gzpt3oTOweFtp305sKD6TVxWOA/OrKHJmVG6fD7z3M6Xg7Nzb0HPnV6BUv kUm5JlzJWiShB8eGgwKGOtwS7S7VF9iqX5f3BmJbqxpkB/RG8nYX7/qxgitiE+83fLEZ IyUbiKL/wcu/IJP9D5CDwyz4cw2K0FExma1kGsLuZd+R5KL+Lu2Kfo33qKOVvthRhUK8 u+FQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=PfOHx/yYiVRDFcplLpIShH9j4DkSNtuEs48LotWh3gY=; b=fL4mL2E1dvPSGA2KTOvJk+RqtCZNryRMl5rr1C4UKUfwjQJBKQsYovYcyqp/cWXbsj v7yYiGROAfDUa0hgH13G77oMqkZcYdZgIgTy9+ooYNeYpgvoSpRL4Nm5dslcKuGpfnc7 8+ElUCEpmZWoDyJyN9rsiqdlswKhi/seT9vTxLGH3yI5OgKt3hxsJV2M0ETGwgOzncDh 0zuWvlwzks+g9UAi097qiqhPetPfd76POIpWarvoAYf88CkUDEJdvKPzoCcZwoL2n7jg M4WnW2kOClUtJpHKSzSwwIOkvddYBRwUYoTul2iewhAJ/yYghyQP7Tp4cEvs5Q3wuJA4 F05Q== X-Gm-Message-State: AOAM5321kCbhRnotrXSccTO4FbnXnNbf7oXNeGgksES4loiy4Ox0bQ5e eYSxA+WzgBI7xVAkyaRo6kaKnapRq5bzRUa8IjD7eQ== X-Google-Smtp-Source: ABdhPJze8Zpd/C2n67fCbfSLN0JpwAjoDpi8a4tVfAxoo8Pwq6gpSAaeHibU58oD+VRCCg75MngUFaV9H29jO2wzmoY= X-Received: by 2002:a25:c095:: with SMTP id c143mr11675278ybf.179.1629825145263; Tue, 24 Aug 2021 10:12:25 -0700 (PDT) MIME-Version: 1.0 References: <20210820010403.946838-1-joshdon@google.com> <20210820010403.946838-5-joshdon@google.com> In-Reply-To: From: Josh Don Date: Tue, 24 Aug 2021 10:12:14 -0700 Message-ID: Subject: Re: [PATCH v3 4/4] sched: adjust sleeper credit for SCHED_IDLE entities To: Jiang Biao Cc: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Paul Turner , Oleg Rombakh , Viresh Kumar , Steve Sistare , Tejun Heo , Rik van Riel , linux-kernel Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 24, 2021 at 1:16 AM Jiang Biao wrote: > > Hi, > > On Fri, 20 Aug 2021 at 09:06, Josh Don wrote: > > > > Give reduced sleeper credit to SCHED_IDLE entities. As a result, woken > > SCHED_IDLE entities will take longer to preempt normal entities. > > > > The benefit of this change is to make it less likely that a newly woken > > SCHED_IDLE entity will preempt a short-running normal entity before it > > blocks. > > > > We still give a small sleeper credit to SCHED_IDLE entities, so that > > idle<->idle competition retains some fairness. > > > > Example: With HZ=1000, spawned four threads affined to one cpu, one of > > which was set to SCHED_IDLE. Without this patch, wakeup latency for the > > SCHED_IDLE thread was ~1-2ms, with the patch the wakeup latency was > > ~5ms. > > > > Signed-off-by: Josh Don > Tried to push a similar patch before, but failed. :) > https://lkml.org/lkml/2020/8/20/1773 > Please pick my Reviewed-by if you don't mind, > Reviewed-by: Jiang Biao Done, thanks :)