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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CEB3DC74A5B for ; Fri, 17 Mar 2023 08:14:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229760AbjCQIOo (ORCPT ); Fri, 17 Mar 2023 04:14:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42886 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229974AbjCQIOe (ORCPT ); Fri, 17 Mar 2023 04:14:34 -0400 Received: from mail-ed1-x535.google.com (mail-ed1-x535.google.com [IPv6:2a00:1450:4864:20::535]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B9F8EBE5EB for ; Fri, 17 Mar 2023 01:13:50 -0700 (PDT) Received: by mail-ed1-x535.google.com with SMTP id r11so17239123edd.5 for ; Fri, 17 Mar 2023 01:13:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1679040824; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=NTkt885oytfYo9Lb68dSckMe6EvhfqmYNTcED2Zhid4=; b=ck1t9nOjPrcc1xukWzZfjhW3Xy1y9jpxRdwbuxWkBc0Zvp/Ezztq+X4SBD/Y4ASzlQ zriqdhO/8JOPDCLmj5c6++19KOLUHljtKGL6zLnR8PkyJWjYq6+Av5VZol6wWb7E2Gpu MZNWZWviB/7MagoiFcNlqx1eGAAO7xlOBiShKxfYd246jd7Yx3OJ2PTeespuWYwr+Z9T DtA79IbYkXPlAvBBhFty1ePYKCLwan5I3DdiNr52bup6jpHitEmddslhINbvREE7114H zhN9Abs673CEDQFu3pgsCpMkmbMAoizArFKk3Pp3J5ofDs/cloqsRNAYawDLUPzM6tQ3 5A6g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1679040824; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=NTkt885oytfYo9Lb68dSckMe6EvhfqmYNTcED2Zhid4=; b=8ATm+Cr+QUOGasPICheXsQ6zbNK5W8kCX0uUO5vXV+OApqnAJvExRy4JQkVhn81Xf6 X72Ck2CrYyp9HZtLESe8J4+rAtTo/ciEj0RidQ5+Qm12EC+SYFDrEOCC5LYgjB529O0C prYYLPdTw2OZAAdZcZwHdXcoPDk0ecLS0PKZVVX/0IoEvQT+5qWoHROAXEySbYQxOi7h juQkEaGdtV8uuMWjlfK9hFsoY9rAB7cMzrt7Bw5iNvNUAxfYTE8zuPbkgzO9NU3miODK qcxBNXKqhNRdmOYRgvOgwtZcpKHBVfAJlF3JHGTh6Z3c3olf7CILM8/clVyfBEfI4vSb THPA== X-Gm-Message-State: AO0yUKUy2ZqDNdWv/zsnrc1wtVsRa/EpmvdDPp00boqK2G+cZVHSPugx yU4O9JBKGtKAIGMMln64MQMqCg== X-Google-Smtp-Source: AK7set+CF7YjQa2Ct2Oo7/j0ML04WAmz9uR1EGipCzOXucb3MWLgpSH22pA/XuGe+u8cXw7Q7KJmuQ== X-Received: by 2002:a17:906:2357:b0:931:829c:9d58 with SMTP id m23-20020a170906235700b00931829c9d58mr2026395eja.23.1679040823826; Fri, 17 Mar 2023 01:13:43 -0700 (PDT) Received: from ?IPV6:2a02:810d:15c0:828:848a:1971:93e0:b465? ([2a02:810d:15c0:828:848a:1971:93e0:b465]) by smtp.gmail.com with ESMTPSA id u27-20020a50951b000000b004bf999f8e57sm710282eda.19.2023.03.17.01.13.42 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 17 Mar 2023 01:13:43 -0700 (PDT) Message-ID: Date: Fri, 17 Mar 2023 09:13:42 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.9.0 Subject: Re: [RFC PATCH] cpufreq: qcom-cpufreq-hw: allow work to be done on other CPU for PREEMPT_RT Content-Language: en-US To: Hillf Danton Cc: Andy Gross , Bjorn Andersson , Konrad Dybcio , "Rafael J. Wysocki" , Viresh Kumar , linux-arm-msm@vger.kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, Adrien Thierry , Brian Masney , linux-rt-users@vger.kernel.org References: <20230315164910.302265-1-krzysztof.kozlowski@linaro.org> <20230316235705.2235-1-hdanton@sina.com> From: Krzysztof Kozlowski In-Reply-To: <20230316235705.2235-1-hdanton@sina.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 17/03/2023 00:57, Hillf Danton wrote: > On 16 Mar 2023 13:28:18 +0100 Krzysztof Kozlowski >> On 15/03/2023 17:49, Krzysztof Kozlowski wrote: >>> Qualcomm cpufreq driver configures interrupts with affinity to each >>> cluster, e.g. dcvsh-irq-0, dcvsh-irq-4 and dcvsh-irq-7 on SM8250. >>> Triggered interrupt will schedule delayed work, but, since workqueue >>> prefers local CPUs, it might get executed on a CPU dedicated to realtime >>> tasks causing unexpected latencies in realtime workload. >>> >>> Use unbound workqueue for such case. This might come with performance >>> or energy penalty, e.g. because of cache miss or when other CPU is >>> sleeping. >>> >>> Signed-off-by: Krzysztof Kozlowski >>> --- >>> drivers/cpufreq/qcom-cpufreq-hw.c | 11 ++++++++++- >> >> Let me also paste impact of this patch - rtla osnoise on entirely idle >> system (cores 2-7 isolated for Realtime): > > Are cores 2-7 the non-housekeeping CPUs[1]? Yes, since their are isolated for Realtime this is synonymous. > > [1] https://lore.kernel.org/lkml/20230223150624.GA29739@lst.de/ Best regards, Krzysztof