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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A7E59C433EF for ; Tue, 5 Oct 2021 14:13:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 89518611F2 for ; Tue, 5 Oct 2021 14:13:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235977AbhJEOPf (ORCPT ); Tue, 5 Oct 2021 10:15:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40968 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235464AbhJEOOI (ORCPT ); Tue, 5 Oct 2021 10:14:08 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2FCCDC061794; Tue, 5 Oct 2021 07:12:15 -0700 (PDT) Date: Tue, 05 Oct 2021 14:12:12 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1633443133; 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=+KkUewm5Vuy2HVgDvqZBxFySJ4Pd+yGWAR2vs2QsjLc=; b=zSJJXGSiPggOb6hu5tG0HfGvhtiLNAY9m/W5GGrTfPtKp3qds6xsTYnvWXn7Sgu51hzCai v6BC6i3lVZtrMk3rpVorJZpgaZ+XCwqICGv2i/rum8IwtyOvbt2MEycJoLMmsvAe8X09Sm GVpIcByNobZqQ/Hrh3gjiJ1yljAKyXuWMWDWCQhk4AA6PxXXcd2+4cXvzUJQ9YK7/kbe+2 wS8HicF7y9+yFUCSpb//UQnHl7CAR6CUn/N6xIRiNPad6F1N9R3I+EI9YF6S21K61ajlvZ u2SbWV41UJxpNkN711bLOWKPwydyNilEXTiKYk7XZyTr1zfohJAklm6/eRmjcw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1633443133; 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=+KkUewm5Vuy2HVgDvqZBxFySJ4Pd+yGWAR2vs2QsjLc=; b=BxU7BBZRAjEse2HHGtVZUpDheYbA75XJ6KnDtnZOpCnB5y0QrGfr23O5zARkc6T7fkkqP4 a5mAnoCMcs2QEqAg== 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: <163344313292.25758.13469550980550076038.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: 2cae3948edd488ebdef4deaf1d1043f92f47e665 Gitweb: https://git.kernel.org/tip/2cae3948edd488ebdef4deaf1d1043f92f47e665 Author: Josh Don AuthorDate: Thu, 19 Aug 2021 18:04:03 -07:00 Committer: Peter Zijlstra CommitterDate: Tue, 05 Oct 2021 15:51:39 +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 d835061..5457c80 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -4230,7 +4230,12 @@ 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