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 38701285C87 for ; Wed, 18 Jun 2025 12:22:14 +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=1750249334; cv=none; b=gXJrqblSr4Kk1YJQaTpvgv3rdFh7WxUJeA42jux7G0qNdGtirLFItJESZ8yGKfn3u6Y91ETIjd+eJWYY7EDstZgx08WsSrbEm3H/MwVzx5Q67HV6evX3ThJHyf0sMX9xL3471rKNlkATi6/aCSuGjM501OS9zMGjueX7msoJvmM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750249334; c=relaxed/simple; bh=JVE/+3sgH3e9JCWN+l4e4TPxHLMo4/QTyRIKzNqrJBg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=igsAWb66hWK6APuuu/lqkU1H1bCV6faQ/qZC0caPHHykvLb6CvgiwW94LRDOsU2ZGcC03tEPxhl4khJjmd2DhlHdz23JDmFm3cnYySUB6dXfuI9DU0N73l3ZM27PYmjBBKf9Q3shQB4y9/XjmnR8uiTYmaQATgq3zcsPJ8aaThs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eaJnwTE7; 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="eaJnwTE7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B3F8BC4CEED; Wed, 18 Jun 2025 12:22:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1750249334; bh=JVE/+3sgH3e9JCWN+l4e4TPxHLMo4/QTyRIKzNqrJBg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=eaJnwTE73J31a7yBaU3MBP7RB9KhCQVL2ec+avCaSzaS/Fnh4UI/IUi7NWpGfz6KW RfJ07Y0et+SYSCHXM1GpASH93CvmDFXkE4fPFj23BGHKfu5KqDe8ijCwgvjYTNYUdn 5pr+rr/UEtkykAxWD0k8AnMWmdxG7mAgyjeXrDsvUEL6DwWGXKmdvBUFWGYc0sVwH7 HDKfHKUKHbi1HvigG14lJA6JVWeMDOWefd3CQ+6LgpFJyrIrwVaozXrZ4DJVN9GRo3 hf+//19mFW6bzaTl5flZODKEo3xy45Y6JrugLc+tSbDoLInwRWhejO9W6tPhO3YwJn C7ap3xyDPu5Wg== Date: Wed, 18 Jun 2025 14:22:11 +0200 From: Frederic Weisbecker To: Gabriele Monaco Cc: linux-kernel@vger.kernel.org, Anna-Maria Behnsen , Thomas Gleixner , Waiman Long Subject: Re: [PATCH v6 0/6] timers: Exclude isolated cpus from timer migation Message-ID: References: <20250530142031.215594-1-gmonaco@redhat.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=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Hi Gabriele, Le Wed, Jun 18, 2025 at 02:17:29PM +0200, Gabriele Monaco a écrit : > On Fri, 2025-05-30 at 16:20 +0200, Gabriele Monaco wrote: > > The timer migration mechanism allows active CPUs to pull timers from > > idle ones to improve the overall idle time. This is however undesired > > when CPU intensive workloads run on isolated cores, as the algorithm > > would move the timers from housekeeping to isolated cores, negatively > > affecting the isolation. > > > > [...] > > > > Exclude isolated cores from the timer migration algorithm, extend the > > concept of unavailable cores, currently used for offline ones, to > > isolated ones: > > * A core is unavailable if isolated or offline; > > * A core is available if isolated and offline; > > > > A core is considered unavailable as isolated if it belongs to: > > * the isolcpus (domain) list > > * an isolated cpuset > > Except if it is: > > * in the nohz_full list (already idle for the hierarchy) > > * the nohz timekeeper core (must be available to handle global > > timers) > > Frederic, Thomas, Waiman, would you have time to review this series? > Thanks, > Gabriele Yes, sorry I got distracted with other things (although quite related). I will give it a priority soonish! Thanks. -- Frederic Weisbecker SUSE Labs