From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 8C7A8D26A for ; Sun, 9 Jun 2024 08:07:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717920454; cv=none; b=EgRK1IRot8mfCQ22ly2ad0AyTQyKW2qjnjNtW/ZcIYqbB28R/MG8C/N62cTaymIIl1dJPYQKC0YliTY9ZOZgp9EWwljK55nolsPEddecrJmfR4xIWa/zB7Qbh3IAchhncNPtMmlPuJ4qoBwvk8Bia6/VEgI6dO7Pem3b3+CsTPk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717920454; c=relaxed/simple; bh=lOSN//yUQFmhLpm5Bd1YqSKVJsxaLRxaQ+D/NYYOnxU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=qWc7kxznnsqlF3o+ZAx9j+TvWjePMKazyLjmct0j4tvdpG0Y0CZnwckZQDK54pW4WNZcmag0TGh2iPZzbJ3aI/JGbIa+at4v2Pb8ElI+Of34rTJGkw4m2vpgA17M7auRgzebqQ/424/2Dq8tO9F+13cpYKt7ZDVZQlazkGu1ecE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=rlFAMsSt; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="rlFAMsSt" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 09BF4C2BD10; Sun, 9 Jun 2024 08:07:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1717920454; bh=lOSN//yUQFmhLpm5Bd1YqSKVJsxaLRxaQ+D/NYYOnxU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=rlFAMsStExGoQBYvuSIo0iDEJHa4iKG/EfmfB9bdHbNXmA4tarjE3A1ad6uuHN8R1 LpsVMw9kUTmTq1i7v2Gw6FgQwOPuFCdwpQk2PHtISl+EAG3nPN0+ABKK2kZ5RQfK6u XIZZdrPv4JeliIHs3ZBUFeV+eKvnpnmZGoAK4XvuWXcthpqEBE/cpWnJu6eycqeSov XfFa+xkYLO/oPjT3NlL2A7fRPWVexwHB6Rb7Ao+47yYMZRfK3Vzg9i3ia0B69hiSab y428LSwwqvuLxOxWlE1e+bVU4IFYj7RV2FvvqqjoHFpDrc9tk6vyfmXe2ezgXMr3W0 1ipplsLYj6eIw== Received: from johan by xi.lan with local (Exim 4.97.1) (envelope-from ) id 1sGDaP-000000006fV-05O9; Sun, 09 Jun 2024 10:07:33 +0200 Date: Sun, 9 Jun 2024 10:07:33 +0200 From: Johan Hovold To: Linus Torvalds Cc: David Laight , Linux Kernel Mailing List Subject: Re: Linux 6.10-rc2 - massive performance regression Message-ID: References: <46cb50d65e414bfd9bef5549d68ae4ea@AcuMS.aculab.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Sat, Jun 08, 2024 at 03:00:43PM -0700, Linus Torvalds wrote: > On Sat, 8 Jun 2024 at 14:36, David Laight wrote: > > I've done some tests. > > I'm seeing a three-fold slow down on: > > $ i=0; while [ $i -lt 1000000 ]; do i=$((i + 1)); done > > which goes from 1 second to 3. > > > > I can run that with ftrace monitoring scheduler events (and a few > > other things) and can't spot anywhere the process isn't running > > for a significant time. > > Sounds like cpu frequency. Almost certainly hw-specific. I went > through that on my Threadripper in the 6.9 timeframe, but I'm not > seeing any issues in this current release. > > If you bisect it, we have somebody to blame and point fingers at... This may possibly be related to the cpufreq/thermal regression I just reported here: https://lore.kernel.org/lkml/ZmVfcEOxmjUHZTSX@hovoldconsulting.com/ which causes the big cores on the Lenovo ThinkPad X13s to be stuck at a low frequency once they've been throttled. Johan