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 E60B4C02198 for ; Wed, 12 Feb 2025 10:05:23 +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:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=dTFlbsmC0WjAMz9CQYs4K20vlagORcevhwzqv7FeHjg=; b=Y8PriJM1Z5keZXop7xYR9ZpRN4 UQ36HVSc6aRBY7lQThHyVKaVo23YH+YVQm0L633dzgcrRJNQBSW2juWYJMICF6Iq2Fc6mb9Mymqq1 8OIHXOAyynLByq8PgF5KlVxVh6z/62WYOikvUNk7c6GuV+MBmDVMtlUvCLdfweT0M+L4+oX+cONP0 ThEQ7UT0UmLKAWiVNL4l67nsY4JoPPLVze7306+z2HeqgKX1UtNy/rXHUBeAAPg8K4Cdm0TcTn3a+ sAj6iM64SjBniqSgkttDZcY/OAdn4nqEstjnZP/YqB5NnRQmcQArPL/haaMAV1Ki66Bn4mhIdAb6v s9fRfq8Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1ti9cH-00000006v94-24Eb; Wed, 12 Feb 2025 10:05:13 +0000 Received: from casper.infradead.org ([2001:8b0:10b:1236::1]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1ti9Gx-00000006py5-02W5 for linux-arm-kernel@bombadil.infradead.org; Wed, 12 Feb 2025 09:43:11 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=dTFlbsmC0WjAMz9CQYs4K20vlagORcevhwzqv7FeHjg=; b=ZKUNfn9YKrc+sODKhuuCqPIHU/ EUk+PNBuuNAGWpkntmcAJcn9aEay6YbmY3I3dW/oNrdv7DjEpodbkwIvrEXh5r7y9pqgb5AO6RNmp 60UY/sNaibBFCkJUkwnZJQmUTee0nsaoWuiWucVdQq7oXBml+IrBw+JdPo7HKwBT/4qrjyju8wUIz A+nZ3rsg7cfauDLma5ZrHC04J5p53wP86aZyxzy2rHyy4/f4Umoc/0iY6Sqz77Uj+xjwtUG7UeZxx bwtUJxO+uE8P+G+WUjuzSt4bR8Z+MzVJKr4mJL90r9FYWDgWZrVEFWs9fSny+N2u9rrJIVeV/sFZC XAbFSFdg==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1ti9Gu-00000004Al6-1Win; Wed, 12 Feb 2025 09:43:08 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id F2CDF300318; Wed, 12 Feb 2025 10:43:07 +0100 (CET) Date: Wed, 12 Feb 2025 10:43:07 +0100 From: Peter Zijlstra To: Cristian Prundeanu Cc: K Prateek Nayak , Hazem Mohamed Abuelfotoh , Ali Saidi , Benjamin Herrenschmidt , Geoff Blake , Csaba Csoma , Bjoern Doebel , Gautham Shenoy , Joseph Salisbury , Dietmar Eggemann , Ingo Molnar , Linus Torvalds , Borislav Petkov , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-tip-commits@vger.kernel.org, x86@kernel.org Subject: Re: [PATCH 0/2] [tip: sched/core] sched: Disable PLACE_LAG and RUN_TO_PARITY and move them to sysctl Message-ID: <20250212094307.GB19118@noisy.programming.kicks-ass.net> References: <20250119110410.GAZ4zcKkx5sCjD5XvH@fat_crate.local> <20250212054113.19938-1-cpru@amazon.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250212054113.19938-1-cpru@amazon.com> 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 On Tue, Feb 11, 2025 at 11:41:13PM -0600, Cristian Prundeanu wrote: > Your find also helps to point out that even when it works, SCHED_BATCH is > a more complex and error prone mitigation than just disabling PL and RTP. > The same reproducer setup that uses systemd to set SCHED_BATCH does show > improvement in 6.12, but not in 6.13+. There may not even be a single > approach that works well on both. > > Conversely, setting NO_PLACE_LAG + NO_RUN_TO_PARITY is simply done at boot > time, and does not require further user effort. For your workload. It will wreck other workloads. Yes, SCHED_BATCH might be more fiddly, but it allows for composition. You can run multiple workloads together and they all behave. Maybe the right thing here is to get mysql patched; so that it will request BATCH itself for the threads that need it.