From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2C89DC433F5 for ; Tue, 2 Nov 2021 00:09:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0B495608FE for ; Tue, 2 Nov 2021 00:09:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231916AbhKBAMJ (ORCPT ); Mon, 1 Nov 2021 20:12:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:55446 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229497AbhKBAMJ (ORCPT ); Mon, 1 Nov 2021 20:12:09 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 1052660EDF; Tue, 2 Nov 2021 00:09:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1635811775; bh=EfZ9nBGWld8QFbfvoTqAhXWUe2i3SVh73ovScpJwvk4=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=ZZhtr1r0n9W4Q5dJ/4squPwswHOmfQjaTpoeZ+ZVh4jR+3CN1KFQS4CQxy+Nuxvr7 SNWNhwNE7hQTbk1du3DWdTHY9gxHjOowm5C1LwELaE3HY0OPXDLi1qFEM2HaTWuJ+O CmfHhuJyPJPz3Ggz20FPsXlUnVoYDnap56r07cDx6ivfu0nPFLn9Ic14kntT8fB9PK opIcmdLKqPC3Lfewz2qxv8skbbV9YG76sLyFhZwgTZpaP+PVw4XxKsEW/R+KD8MnWz K0iz0Q9kt3293NAPQ7AopR3ZTxct4aRkSYG8VL8FE8pWAAwYJp/NeK8naK0lvamU9v Tcmgbz/vKDSIA== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id D06115C037F; Mon, 1 Nov 2021 17:09:34 -0700 (PDT) Date: Mon, 1 Nov 2021 17:09:34 -0700 From: "Paul E. McKenney" To: Jiri Wiesner Cc: Thomas Gleixner , Mel Gorman , LKML , Linux-Net Subject: Re: [RFC PATCH] clocksource: increase watchdog retries Message-ID: <20211102000934.GG880162@paulmck-ThinkPad-P17-Gen-1> Reply-To: paulmck@kernel.org References: <20211027164352.GA23273@incl> <20211027213829.GB880162@paulmck-ThinkPad-P17-Gen-1> <20211028162025.GA1068@incl> <20211028184209.GH880162@paulmck-ThinkPad-P17-Gen-1> <20211101102803.GA16089@incl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211101102803.GA16089@incl> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, Nov 01, 2021 at 11:28:03AM +0100, Jiri Wiesner wrote: > On Thu, Oct 28, 2021 at 11:42:09AM -0700, Paul E. McKenney wrote: > > On Thu, Oct 28, 2021 at 06:20:25PM +0200, Jiri Wiesner wrote: > > > On Wed, Oct 27, 2021 at 02:38:29PM -0700, Paul E. McKenney wrote: > > > > I had something like this pending, but people came up with other workloads > > > > that resulted in repeated delays. In those cases, it does not make sense > > > > to ever mark the affected clocksource unstable. This led me to the patch > > > > shown below, which splats after about 100 consecutive long-delay retries, > > > > but which avoids marking the clocksource unstable. This is queued on -rcu. > > > > > > > > Does this work for you? > > > > > > > > commit 9ec2a03bbf4bee3d9fbc02a402dee36efafc5a2d > > > > Author: Paul E. McKenney > > > > Date: Thu May 27 11:03:28 2021 -0700 > > > > > > > > clocksource: Forgive repeated long-latency watchdog clocksource reads > > > > > > Yes, it does. I have done 100 reboots of the testing machine (running > > > 5.15-rc5 with the above patch applied) and TSC was stable every time. I > > > am going to start a longer test of 300 reboots for good measure and > > > report back next week. J. > > > > Very good, and thank you for giving it a go! > > Thank you for the fix! It resolves several strange results we got in our performance testing. > > > If it passes the upcoming tests > > I have done 300 reboots of the testing machine. Again, TSC was stable every time. > > > may I have your Tested-by? > > Absolutely: > Tested-by: Jiri Wiesner Applied, thank you! Thanx, Paul