From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from www74.your-server.de (www74.your-server.de [213.133.104.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C3FC0380FF1; Mon, 31 Aug 2026 18:49:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.133.104.74 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788202184; cv=none; b=rljihJFxrjTojTXf3CXW89e9s2oUjcEca89dndj8A6V94nzB6oaw23HJL09qB/lqHmHiq76ANwvcsqkYXNhvMQJhnrZxqj0jqhCKCOFkoFzJhS3qHz8a/4L2Ezoz7RfAsDyYQx7L75DBEOzQgQWPlmSRCwvqC9HzCPn+xZYuEgw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788202184; c=relaxed/simple; bh=hTGudjtpdSOtOrAOCrFcB4XC3BXnwQSa0ef2M+jtzV0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=PddE8C+gb1WHiyn46hmeOPr5ja5L5Jf6i8hmRh0U3T82bRh+B0yjkF+zWhHUIAOmFrJxBSWHhvQC9umI3M6Anh+OgFsGuN7GDXX13FBLT4//xn2au32V9mK/Bvp8umm8RxHEKbUUEpdg2OSGE+3mBe/xJdFo0GcbQHTGJhCnM0Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=computerix.info; spf=pass smtp.mailfrom=computerix.info; dkim=pass (2048-bit key) header.d=computerix.info header.i=@computerix.info header.b=EG3KKG1N; arc=none smtp.client-ip=213.133.104.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=computerix.info Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=computerix.info Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=computerix.info header.i=@computerix.info header.b="EG3KKG1N" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=computerix.info; s=default2306; h=Content-Transfer-Encoding:Content-Type: In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID; bh=UV1gM1U2p8jHqQ3spHsXWtQidWRgEuz/1lspV0W9kXs=; b=EG3KKG1NYSezy0W2lQR8oHm7i0 WNb40Y+XQZuUZcqmN3KOGHCmHV/A8HNJZD1g+dvQBdkGQR4ot6rquFFDG0eq2JG07nUmU0alIH8s7 ZxrUnygvGBjnXNlsaczsk9GS3UhaXG6JF16mBLyWqAjCRiLcsj1xOdWTa4gmjzO31ydd1z+4evLEl pVZ1RqtgbNG3kO02QnDuqgSDBKih02e3g+soJ1YMZuInPIHN7yiJg48513KArp9dh9xTazDbyG8Xv qhV0ARfDffisIp7XR0YTm2SXVPqOMcfpZiY4yqpFdhYwi7MLDrqlWw+PX34SW6rbc4thmo2OvKsBp oKhgfIpQ==; Received: from sslproxy04.your-server.de ([78.46.152.42]) by www74.your-server.de with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.96.2) (envelope-from ) id 1x174Y-000BE3-1P; Mon, 31 Aug 2026 20:49:34 +0200 Received: from localhost ([127.0.0.1]) by sslproxy04.your-server.de with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1x174X-000He4-2J; Mon, 31 Aug 2026 20:49:33 +0200 Message-ID: <3a8985e1-77b4-4127-af0a-ec1c397eb1ad@computerix.info> Date: Mon, 31 Aug 2026 20:49:32 +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: Cache-aware scheduling does not work well with amd big/little cores Content-Language: en-US To: Tim Chen , "Chen, Yu C" , Mario Limonciello Cc: "Badole, Vishal" , Peter Zijlstra , linux-kernel@vger.kernel.org, "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , platform-driver-x86@vger.kernel.org, K Prateek Nayak , ricardo.neri@intel.com References: <2180ea5a-eb28-4152-8d4d-cd00b0c24b2e@computerix.info> <8064e1d8-b51c-48e5-a312-8c31581991f5@amd.com> <369d0bbb-db7a-4f86-bee2-332d5295c452@computerix.info> <406a5c407bbe60cafc24f715e089f5552a0791f9.camel@linux.intel.com> From: Klaus Kusche In-Reply-To: <406a5c407bbe60cafc24f715e089f5552a0791f9.camel@linux.intel.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Virus-Scanned: Clear (ClamAV 1.4.3/28109/Mon Aug 31 08:24:07 2026) This would need some more testing efforts, because all my kernels are built without debugfs (using an earlier version of Mario's patch), and without Mario's patch and without debugfs, I don't get any big/little scheduling at all. So I'd need to build and test with debugfs (tomorrow I'm on a mountain tour, perhaps later this week). Prof. Dr. Klaus Kusche Privat: Söllmnitz 32 d, D-07554 Gera/Söllmnitz 036695/859909 klaus.kusche@computerix.info https://www.computerix.info Dienstlich: DHGE Gera, Weg der Freundschaft 4, D-07546 Gera klaus.kusche@dhge.de https://www.dhge.de On 31/08/2026 19:29, Tim Chen wrote: > On Mon, 2026-08-31 at 13:24 +0200, Klaus Kusche wrote: >> Hello, >> >> both patches in combination seem to have the desired effect. >> >> But I just look at a bar graph showing the current load >> of each core. >> The graph suggests that long-running CPU-intensive processes >> migrate to fast cores when fast cores become available. >> And I have the impression that LTO compilations >> finish significantly faster now. >> >> I don't have exact numbers or benchmarks. > > Thanks for testing the fix. > > If you just apply https://lore.kernel.org/lkml/20260825174112.2580942-1-tim.c.chen@linux.intel.com/, > with default aggr_tolerance, what numbers do you see? > > That will be helpful for further tuning. Thanks. > > Tim