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 7DF0B24337B; Sun, 8 Mar 2026 09:53:37 +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=1772963617; cv=none; b=MEcJU7IWgTwMfTLOzFLXh5qbHeVMte4mtCLP/FKgNiwW23Ys+SlZkWG/IByE1fz6lXH277pUr/gUqVtJ9EaynpIStGV3LgrkIZ+VJHQjbDj8KlzylVu9tvAteH7JmXaPymj7xzHKnwF7WuqKzZmx0lf9MYT4bla4AtlJcgwYdtE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772963617; c=relaxed/simple; bh=YpZtJeyi3j9I0kfeXGeyMC/v7uGkAInhYxZIAZcLHiQ=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=MUt/xVo9SbeSRAqZ/rs9+RcbR4UyJyAHjGZ0i9O35nvSTOqXvefa7TMz1QeBHBGwEEV3Nj8W+OAFvUYsHERlrJICjAikwedLJ6qzZL7fVAEckKBogIzPv0jqvI3fAsXZ+ntMSTmhxfvOVtTZv8zuD9gHeTFFWTcyNZkKMD6boVY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RTvqX2Cq; 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="RTvqX2Cq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 32853C116C6; Sun, 8 Mar 2026 09:53:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772963617; bh=YpZtJeyi3j9I0kfeXGeyMC/v7uGkAInhYxZIAZcLHiQ=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=RTvqX2CqsybrPAeVVoaqazFAFJGPkzei6O1n7GY6qEkv/iYa6ukUEu/sS4eQnM78A WR5rowPbwDsAaeuq0az4AZS+jNa1eDlcvcmtDEo4J5x4dcJzgLMVLTVrEZ+lzMLSxU px2sMA+SBJpkVYHNsU67xLXUuQNCwCuG4YSCNz/IfeBpO+1szqfsy7b1FRJ4MqgKa6 yXz2NjoRBL66CBeMhyDgnE46+3zNstyZJhWXSiuvddb27D2U2gtOMJTvF2vFsUawZR W1rTO+qCe73tKbQbVsFX21SE4hm/nJcevFlDr8H/aqUhD85PPNTu7m/JQsikdRK5+Q QGQqHRMjy0UDg== From: Thomas Gleixner To: Daniel J Blueman Cc: LKML , "Paul E. McKenney" , John Stultz , Waiman Long , Peter Zijlstra , Daniel Lezcano , Stephen Boyd , x86@kernel.org, "Gautham R. Shenoy" , Jiri Wiesner , Scott Hamilton , Helge Deller , linux-parisc@vger.kernel.org, Thomas Bogendoerfer , linux-mips@vger.kernel.org Subject: Re: [patch 5/5] clocksource: Rewrite watchdog code completely In-Reply-To: <87ms0zva5i.ffs@tglx> References: <20260123230651.688818373@kernel.org> <20260123231521.926490888@kernel.org> <87jywvfkrs.ffs@tglx> <87ms0zva5i.ffs@tglx> Date: Sun, 08 Mar 2026 10:53:33 +0100 Message-ID: <871phu3aw2.ffs@tglx> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Daniel! On Mon, Feb 23 2026 at 14:53, Thomas Gleixner wrote: > On Sun, Feb 15 2026 at 20:18, Daniel J Blueman wrote: >> On Mon, 2 Feb 2026 at 19:27, Thomas Gleixner wrote: >> Good step forward! We can also reduce remote cacheline invalidation by >> putting 'seq' into the cacheline after 'cpu_ts' by reordering: > > Good point. > >> With that said, with your latest change on the 1920 thread setup, >> WATCHDOG_READOUT_MAX_US 1000 is still needed to avoid timeouts during >> the previous adverse workload, however some timeouts are still seen >> during massive parallel process teardowns. >> >> To limit overhead, perhaps it is sufficient to set the timeout to >> 100us, avoid retries (as the hardware thread may continue to be busy >> and will be rechecked later anyway), and log timeouts at the debug >> level if at all. > > Something like the below should work even with 50us. I left the print at > INFO level for now. We can either change it to pr_info_once() or to > debug as you said. Any chance you can give this a test ride on that 1920 thread monstrosity? Thanks, tglx