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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 4E514D2F7D5 for ; Thu, 17 Oct 2024 05:23:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type: Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-ID:Date :Subject:CC:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=mWe2YeZ80uokwCci72Iww2HMukKBNuati+Itectcv9I=; b=DmcE969Ujdbao24cxWoXRkTbjq RuunjD9lGs3cRQHtOBhV6E9cOcNJiZNUdkZ+q/C1d+KXYS1fS3y1uwUN2a/IxTWxkDUBzGOiW+dkG u+rdZ+u1Y0G4XgvZkrMSkzTty5EpeT4OzokpjdzP9inqzPj0SF75ehNwFF8Lvh4OaOB8rpu+RlDGk uEU+jiMawe5AcaEnei0b9ikJLutA2bjnq9yBtWaslddgvGu1zNW6kgw1fFXWgMC9ECNwC0qKIgZKH rbUgTGYiaESjQjzr5p+xIfN4oPxFsGnrrzF+JPasrbQHwpRyzGp14jjnxf3R7P/9tC6nOdXZKsk5g VSsLMIIA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1t1Iyk-0000000DmaE-23uy; Thu, 17 Oct 2024 05:23:18 +0000 Received: from smtp-fw-52003.amazon.com ([52.119.213.152]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1t1Ivx-0000000DmGp-3J5Q for linux-arm-kernel@lists.infradead.org; Thu, 17 Oct 2024 05:20:27 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1729142426; x=1760678426; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=mWe2YeZ80uokwCci72Iww2HMukKBNuati+Itectcv9I=; b=upi7vl8yEBw+oGl6cmoBZpVgnOnQXkZ5Db6iyunnDO5U9nvshcJp0qgz +aHpAnDUXnwZPu2R5kj0Z3JDN/rO9aHF9QqxaLJ0UTYgQycI9ME8yVARm iJvxlAnBV2SlBfOUuv0/XfIngIjbn472m2l408sqvWT0UYPYlDo3jRHDH 4=; X-IronPort-AV: E=Sophos;i="6.11,210,1725321600"; d="scan'208";a="33914739" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO smtpout.prod.us-west-2.prod.farcaster.email.amazon.dev) ([10.43.8.6]) by smtp-border-fw-52003.iad7.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Oct 2024 05:20:23 +0000 Received: from EX19MTAUWA001.ant.amazon.com [10.0.7.35:22077] by smtpin.naws.us-west-2.prod.farcaster.email.amazon.dev [10.0.0.29:2525] with esmtp (Farcaster) id 12569ee5-0466-4090-aa2d-ce74ca440d4c; Thu, 17 Oct 2024 05:20:22 +0000 (UTC) X-Farcaster-Flow-ID: 12569ee5-0466-4090-aa2d-ce74ca440d4c Received: from EX19D016UWA004.ant.amazon.com (10.13.139.119) by EX19MTAUWA001.ant.amazon.com (10.250.64.218) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1258.34; Thu, 17 Oct 2024 05:20:22 +0000 Received: from 88665a51a6b2.amazon.com (10.106.178.54) by EX19D016UWA004.ant.amazon.com (10.13.139.119) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1258.34; Thu, 17 Oct 2024 05:20:20 +0000 From: Cristian Prundeanu To: CC: , Peter Zijlstra , Ingo Molnar , , , Bjoern Doebel , Hazem Mohamed Abuelfotoh , Geoff Blake , Ali Saidi , Csaba Csoma , Cristian Prundeanu , Subject: [PATCH 1/2] [tip: sched/core] sched: Disable PLACE_LAG and RUN_TO_PARITY Date: Thu, 17 Oct 2024 00:19:59 -0500 Message-ID: <20241017052000.99200-2-cpru@amazon.com> X-Mailer: git-send-email 2.46.2 In-Reply-To: <20241017052000.99200-1-cpru@amazon.com> References: <20241017052000.99200-1-cpru@amazon.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Originating-IP: [10.106.178.54] X-ClientProxiedBy: EX19D044UWA004.ant.amazon.com (10.13.139.7) To EX19D016UWA004.ant.amazon.com (10.13.139.119) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241016_222026_032971_E2DABAF3 X-CRM114-Status: GOOD ( 12.34 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org With these features are enabled, the EEVDF scheduler introduces a large performance degradation, observed in multiple database tests on kernel versions using EEVDF, across multiple architectures (x86, aarch64, amd64) and CPU generations. Disable the features to minimize default performance impact. Cc: # 6.6.x Fixes: 86bfbb7ce4f6 ("sched/fair: Add lag based placement") Fixes: 63304558ba5d ("sched/eevdf: Curb wakeup-preemption") Signed-off-by: Cristian Prundeanu --- kernel/sched/features.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/sched/features.h b/kernel/sched/features.h index a3d331dd2d8f..8a5ca80665b3 100644 --- a/kernel/sched/features.h +++ b/kernel/sched/features.h @@ -4,7 +4,7 @@ * Using the avg_vruntime, do the right thing and preserve lag across * sleep+wake cycles. EEVDF placement strategy #1, #2 if disabled. */ -SCHED_FEAT(PLACE_LAG, true) +SCHED_FEAT(PLACE_LAG, false) /* * Give new tasks half a slice to ease into the competition. */ @@ -17,7 +17,7 @@ SCHED_FEAT(PLACE_REL_DEADLINE, true) * Inhibit (wakeup) preemption until the current task has either matched the * 0-lag point or until is has exhausted it's slice. */ -SCHED_FEAT(RUN_TO_PARITY, true) +SCHED_FEAT(RUN_TO_PARITY, false) /* * Allow wakeup of tasks with a shorter slice to cancel RUN_TO_PARITY for * current. -- 2.40.1