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18 Oct 2024 09:54:33 +0000 Received: from EX19MTAEUA002.ant.amazon.com [10.0.10.100:35414] by smtpin.naws.eu-west-1.prod.farcaster.email.amazon.dev [10.0.47.49:2525] with esmtp (Farcaster) id 33701318-bce5-4192-970c-29155082d837; Fri, 18 Oct 2024 09:54:30 +0000 (UTC) X-Farcaster-Flow-ID: 33701318-bce5-4192-970c-29155082d837 Received: from EX19D018EUA004.ant.amazon.com (10.252.50.85) by EX19MTAEUA002.ant.amazon.com (10.252.50.126) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1258.34; Fri, 18 Oct 2024 09:54:30 +0000 Received: from [192.168.198.222] (10.106.83.41) by EX19D018EUA004.ant.amazon.com (10.252.50.85) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1258.34; Fri, 18 Oct 2024 09:54:30 +0000 Message-ID: Date: Fri, 18 Oct 2024 10:54:19 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird To: "Prundeanu, Cristian" , Peter Zijlstra CC: "linux-tip-commits@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Ingo Molnar , "x86@kernel.org" , "linux-arm-kernel@lists.infradead.org" , "Doebel, Bjoern" , "Blake, Geoff" , "Saidi, Ali" , "Csoma, Csaba" , "gautham.shenoy@amd.com" References: <20241017052000.99200-1-cpru@amazon.com> <20241017091036.GT16066@noisy.programming.kicks-ass.net> <70D6B66E-B4BC-4A92-9A23-0DADE9B8C3FE@amazon.com> Content-Language: en-US From: "Mohamed Abuelfotoh, Hazem" In-Reply-To: <70D6B66E-B4BC-4A92-9A23-0DADE9B8C3FE@amazon.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.106.83.41] X-ClientProxiedBy: EX19D004EUA004.ant.amazon.com (10.252.50.183) To EX19D018EUA004.ant.amazon.com (10.252.50.85) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241018_025438_376538_43BF1949 X-CRM114-Status: GOOD ( 11.58 ) 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 >> And sysctl is arguably more of an ABI than debugfs, which >> doesn't really sound suitable for workaround. >> >> And I don't see how adding a line to /etc/rc.local is harder than adding >> a line to /etc/sysctl.conf > > Adding a line is equally difficult both ways, you're right. But aren't > most distros better equipped to manage (persist, modify, automate) sysctl > parameters in a standardized manner? > Whereas rc.local seems more "individual need / edge case" oriented. For > instance: changes are done by editing the file, which is poorly scriptable > (unlike the sysctl command, which is a unified interface that reconciles > changes); the load order is also typically late in the boot stage, making > it not an ideal place for settings that affect system processes. > I'd add to what Cristian mentioned is that having these tunables as sysctls will make them more detectable to the end users because checking output of sysctl -a is usually one of the first steps during performance troubleshooting vs checking /sys/kernel/debug/sched/ files so it's easier for people to spot these configurations as sysctls if they notice performance difference after upgrading the kernel. Hazem