From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 37BBF28C5A3 for ; Wed, 10 Sep 2025 12:29:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757507362; cv=none; b=j0SVtbQq8rhMEoFgREUdLCQ3YhbtTWrEAzTchL8QQPnLmu2H7k/AuQzMPwxWGp/gj1hed+fFv6oqCSdTT3W7M3MxoNbKI7L8HuYZJMP8e4zhhwM8gO4CuNZQ+ZylhX8+seLJLRYV1QjdsA1KuilH2BGko9Ix7NU6oIj4/imZESY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757507362; c=relaxed/simple; bh=VjeS1Oq6pZ2M0Y0kHRCEkN09rm3/MU2O5a5jPzXpsjQ=; h=Message-ID:Date:MIME-Version:Subject:To:References:From: In-Reply-To:Content-Type; b=DleGcAW8HtpWwJGh1uI9oUwjB5O8o6BTHHP9LecvAyYAgb1IzR137IhFKmy+FMfsPXcQUIrj+CuSseZUeYwiQ9oFibJ45bKS4mrJ33f3xzv77fBDgg7uFOBW0SMHQWyNpC2bnifaLyqyVcBv31E51rp5TioT3TJdzfjCIaqDegs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0249C16F8; Wed, 10 Sep 2025 05:29:11 -0700 (PDT) Received: from [192.168.178.6] (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4EF183F694; Wed, 10 Sep 2025 05:29:18 -0700 (PDT) Message-ID: Date: Wed, 10 Sep 2025 14:29:02 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] sched/fair: bump sd->max_newidle_lb_cost when newidle balance fails To: Ryan Roberts , Chris Mason , peterz@infradead.org, vincent.guittot@linaro.org, linux-kernel@vger.kernel.org, Aishwarya Rambhadran References: <20250626144017.1510594-2-clm@fb.com> Content-Language: en-GB From: Dietmar Eggemann In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 07.09.25 20:21, Ryan Roberts wrote: > On 26/06/2025 15:39, Chris Mason wrote: [...] > I'm seeing a ~25% regression in requests per second for an nginx workload in > 6.17-rc4 compared with 6.16, when the number of simulated clients (threads) is > high (1000). Bisection led me to this patch. The workload is running on an > AmpereOne (arm64) system with 192 CPUs. FWIW, I don't see the regression on an > AWS Graviton3 system. Can you look for any sched domain hierarchy differences between AmpereOne and Grav3? I assume Grav3 is bare-metal? > I'm also seeing a 10% regression on the same system for a MySQL workload; but I > haven't yet bisected that one - I'll report back if that turns out to be due to > this too. Is this the hammerdb test in which the SUT hosts the mysqld? Which params (#Virtual Users, #Warehouses, ...) were you using? > I saw that there was a regression raised against this patch by kernel test robot > for unixbench.throughput back in July, but it didn't look like it got resolved. Can you run the unixbench shell1 test on AmpereOne to see if the regression in nginx is related to this unixbench test? [...]