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 0B08236C598 for ; Tue, 17 Feb 2026 14:37:46 +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=1771339068; cv=none; b=C3ZGG6T36Cqi8+dkoLH0+QMHs2aCtlFb1dribGtrzL0iNLlg5WoJqPoBkSgNjF8RVXG8csNvj7OH1N7NPlG1nmWMPs80E7rX5xJBlkktFpqAQ7bA2CsuUbd4NA6QsscMME0sKoLEwhluCs11hogNtTBMp0WsFR2fT52QDmz85Rs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771339068; c=relaxed/simple; bh=TUyzOZVwkqGl5w5hRUGOyopbsLru/nDysd7iUxXvqMg=; h=Message-ID:Date:MIME-Version:Subject:From:To:Cc:References: In-Reply-To:Content-Type; b=tgUnOy0Kj3to9DS8KtfhafpY3MhTDTjG2bAgW2aiXfKoQ17GLN0NbM41BK2AndkvrG7I+/I2n12EEfwqZ+0lpid5aoTCSpKqDU66thXPpKPvxGLdnUfwYGwKtywxfLs9dcZO1TN05CQWtK0u7CxH6LzaiXOfug1bI0x/J615HvU= 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 ED8EF1477; Tue, 17 Feb 2026 06:37:39 -0800 (PST) Received: from [10.57.55.225] (unknown [10.57.55.225]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 2B08F3FD09; Tue, 17 Feb 2026 06:37:43 -0800 (PST) Message-ID: <29667d6e-38f7-4c8c-86df-5c8fb6b9caa5@arm.com> Date: Tue, 17 Feb 2026 15:37:41 +0100 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 0/4] sched: Various reweight_entity() fixes From: Dietmar Eggemann To: K Prateek Nayak , Shubhang Kaushik , Peter Zijlstra , mingo@kernel.org Cc: juri.lelli@redhat.com, vincent.guittot@linaro.org, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, linux-kernel@vger.kernel.org, wangtao554@huawei.com, quzicheng@huawei.com, wuyun.abel@bytedance.com, dsmythies@telus.net References: <20260130093439.803225718@infradead.org> <13dff84d-8e40-0248-971f-e731dfb18d70@os.amperecomputing.com> <3eefd122-22e5-4ac1-bcaf-fd7016c77bf2@amd.com> <0b9faa96-e06f-4fbd-a16b-23c94bad6b02@arm.com> Content-Language: en-GB In-Reply-To: <0b9faa96-e06f-4fbd-a16b-23c94bad6b02@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 16.02.26 11:59, Dietmar Eggemann wrote: > On 16.02.26 04:14, K Prateek Nayak wrote: >> Hello Shubhang, >> >> On 2/14/2026 12:50 PM, Shubhang Kaushik wrote: >>> Hi Peter, >>> >>> On Fri, 30 Jan 2026, Peter Zijlstra wrote: [...] > I saw the same issue on my Arm64 big.Little board (12 CPUs) with the old > 'queue.git sched/core' (i.e before s/div_s64()/div64_long()) in: > > sched/fair: Increase weight bits for avg_vruntime > > and test: > > for ((i=0; i<20000; i++)) do yes > /dev/null & done > > It's gone with: > > git.kernel.org/pub/scm/linux/kernel/git/peterz/queue.git sched/core > > commit bdba3187771c ("sched/fair: Use full weight to __calc_delta()") > > Tested-by: Dietmar Eggemann > > [...] No regression spotted on 'hammerdb - mysqld' ('client/LDG - server/SUT' running on different ARM64 VMs) AWS VM LDG (c7g.16xlarge) and SUT (m7gd.16xlarge ('maxcpus=16 nr_cpus=16'). Kernel | Throughput | P50 latency. | aarch64 | (NOPM) | (larger is worse) | --------------------+-------------+-------------------+ tip sched/core * | baseline | baseline | queue sched/core ** | +0.8% | -1.0% | --------------------+-------------+-------------------- * e34881c84c25 - sched: Re-evaluate scheduling when migrating queued tasks out of throttled cgroups (2026-02-03 Zicheng Qu) ** bdba3187771c - sched/fair: Use full weight to __calc_delta() (2026-02-13 Peter Zijlstra)