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=-20.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 5E73CC433F5 for ; Thu, 9 Sep 2021 11:18:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 41D87611BF for ; Thu, 9 Sep 2021 11:18:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235778AbhIILTt (ORCPT ); Thu, 9 Sep 2021 07:19:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58930 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235274AbhIILTi (ORCPT ); Thu, 9 Sep 2021 07:19:38 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F02FDC061575; Thu, 9 Sep 2021 04:18:28 -0700 (PDT) Date: Thu, 09 Sep 2021 11:18:26 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1631186307; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=WbYZBOLYppd4RViqwb2ZQ+/T98pvJqsorn1eVX3FCzs=; b=0JP3z42VWwWj7BEI1hyIEp+27tmgOqZ72KF/LDqVwU5gsI7O/TJpjvP5//AiWesBCysTpe 9Hrw969pp/OL8tDeRT/MJpQ1+skhEN5smQVo1Cm38CZmFDqsdB8ITA7+BXg6JE7gPX2VfZ rHjLcyyiwN1v1HVbMDiIx+tB+8kRoVVjaFCVHLpjSTdZMtzarTjyfO1N5gMq4S6PG9G98U YswR+aA1OrRv9HFxaSZ8TajL2pJ6zH443xGPlBVkaZJD6CdjwZIesDowjzdGBFmMl/x+cL 4NeUo4VLd6pbb7+ptGHvcsQrqU8cuFCNC/dGADN2wolNVvsdUPB2a6N+0LIiiQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1631186307; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=WbYZBOLYppd4RViqwb2ZQ+/T98pvJqsorn1eVX3FCzs=; b=EjNNN/8iDEZr86AZmabhqzgo8l7FuTzK681nxgkySPIXfcePrRHfuH0Q3POmh+aNjDzXmM 4rgkiQcAVQHIJsDQ== From: "tip-bot2 for Josh Don" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: sched/core] sched: adjust sleeper credit for SCHED_IDLE entities Cc: Josh Don , "Peter Zijlstra (Intel)" , Vincent Guittot , Jiang Biao , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20210820010403.946838-5-joshdon@google.com> References: <20210820010403.946838-5-joshdon@google.com> MIME-Version: 1.0 Message-ID: <163118630675.25758.7642437893126433247.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the sched/core branch of tip: Commit-ID: bb1fc3bc521782d018902143c8301ab4a5e53557 Gitweb: https://git.kernel.org/tip/bb1fc3bc521782d018902143c8301ab4a5e53557 Author: Josh Don AuthorDate: Thu, 19 Aug 2021 18:04:03 -07:00 Committer: Peter Zijlstra CommitterDate: Thu, 09 Sep 2021 11:27:31 +02:00 sched: adjust sleeper credit for SCHED_IDLE entities 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 Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Vincent Guittot Reviewed-by: Jiang Biao Link: https://lore.kernel.org/r/20210820010403.946838-5-joshdon@google.com --- kernel/sched/fair.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 7330a77..b27ed8b 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4201,7 +4201,12 @@ place_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int initial) /* sleeps up to a single latency don't count. */ if (!initial) { - unsigned long thresh = sysctl_sched_latency; + unsigned long thresh; + + if (se_is_idle(se)) + thresh = sysctl_sched_min_granularity; + else + thresh = sysctl_sched_latency; /* * Halve their sleep time's effect, to allow