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 154FF2F6918 for ; Tue, 14 Apr 2026 15:49:16 +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=1776181759; cv=none; b=O1qaRI7P/Eg+1h1s2/MFWzKytaTaa/HkBkYM875Yjcsd+9s0sk6SxIlBVe+WYn0ZLDonzSRsLG2MMMh7hQIF2PkFivQgoNP2nev5lVGvbQgMnOHe8XDyjfTbaBTW6e7DoYPK3qd1+1XCu5WFX9spqjJN0AFWmvcnfmGzCDle2Eo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776181759; c=relaxed/simple; bh=/GLcptXqbj8jkDgWFGfA+jIqB8QH3pJ/DxhHsveTuyE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ucBwtqX7EQo6Nk/jgLB1GO3RWJ0snHq7L73hpHAlMNgrQVRO/DLQV1FDTL3yA02Ecy8N7fOo9wE6SP2IGtnX/V0rBJr5X+KelpS2OmdhjVpf0mgjXJ4SWi/N46O3wqk5KPmRSr8Yg1PREC8gbl6ivpG1NW1iqo5ksOPU4x+uPe4= 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; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=UenPMeBo; 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 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="UenPMeBo" 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 1FBBC4F4F; Tue, 14 Apr 2026 08:49:10 -0700 (PDT) Received: from [10.1.27.133] (R40MDXPJLG.cambridge.arm.com [10.1.27.133]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 504413F7B4; Tue, 14 Apr 2026 08:49:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1776181755; bh=/GLcptXqbj8jkDgWFGfA+jIqB8QH3pJ/DxhHsveTuyE=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=UenPMeBoKFJIx7U65Hg3MOVQjsN4Y6ZRJZEOdxqZRLeFgdjlE6QX4vp6pl22yvW3U ddD6D8gawv3Q4YjMWVaVR0xzQ/Ao3R9GP626FpXOYlWK1ZbIB9N92/U4THLStBIdxl 2BIZTwSnrIc0pLjOLgc6P/SAdcHOBElc5lqehOgw= Message-ID: Date: Tue, 14 Apr 2026 16:49:11 +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: [Question] Sched: Severe scheduling latency (>10s) observed on kernel 6.12 with specific workload To: Xuewen Yan Cc: Vincent Guittot , John Stultz , Peter Zijlstra , Ingo Molnar , Juri Lelli , Steven Rostedt , Benjamin Segall , Mel Gorman , Valentin Schneider , linux-kernel , =?UTF-8?B?546L56eRIChLZSBXYW5nKQ==?= , Xuewen Yan , "hongyu.jin@unisoc.com" , guohua.yan@unisoc.com References: <1c0e5a70-22b7-4cbd-8ca9-0a7da27ed7a9@arm.com> <89c464b5-908d-4817-87f4-d8cb905495a4@arm.com> <3ed0139b-9e34-491d-80cf-e818fadadd06@arm.com> Content-Language: en-GB From: Dietmar Eggemann In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 14.04.26 06:18, Xuewen Yan wrote: > Thanks Dietmar! > > On Fri, Apr 10, 2026 at 7:14 PM Dietmar Eggemann > wrote: >> >> On 08.04.26 03:50, Xuewen Yan wrote: >>> Hi Dietmar and Vincent, [...] > We tested in Android tree without any vendorhooks. > Just as John said, after we revert commit 6d71a9c61604 ("sched/fair: > Fix EEVDF entity > placement bug causing scheduling lag") in android16-6.12, the latency > disappeared, because the commit is not exist in stable tree. > > On the other hand, we also tested the android17-6.18, without any > revert, the latency still exist. So it's not about the wu_lat of the rt-app tasks but the latency values of the cyclictest tasks? cyclictest -m -t -a --policy=SCHED_OTHER -b 1000000 -D 120s [...]