From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from elvis.franken.de (elvis.franken.de [193.175.24.41]) by smtp.subspace.kernel.org (Postfix) with ESMTP id A39A31DED6F; Mon, 28 Oct 2024 15:48:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.175.24.41 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730130507; cv=none; b=D1D8unJm9XGDEmsSQ+2hYi54kwMVnvkrIXZ/57aOCzi+zM0EQJnqiRFi+KO/lVwteB9ron5T2lcM8PlFduFQorhHFyGqNiKEYdsnHdDPaK1/0S3aGZbuLYDXkEFjbeBXnuwepmE0T/UiWBGMnUH8i+B8r8MFNRDnmGomXjlk1ts= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730130507; c=relaxed/simple; bh=ZRrch4ootEJ4ULxIvELRcvNDg+SmNed42LOYCz5Vd28=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Au3lHBZ4sdLCvIQMlRdZy+xKz3zqHCiX0yd7zWIl2bzvQE861I6ICacTwK/j2Seo2pFJCAOr1r+QCmNW/LkGStURDC7Kqz5cbx8+Q8E4gI49nmws94b3We0oZGF3vnzPkFioSVkfAkncR/Dsoyi3aDUDEzqg05iQtALt/r7H6nQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=alpha.franken.de; spf=pass smtp.mailfrom=alpha.franken.de; arc=none smtp.client-ip=193.175.24.41 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=alpha.franken.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=alpha.franken.de Received: from uucp by elvis.franken.de with local-rmail (Exim 3.36 #1) id 1t5RyE-0005Ir-00; Mon, 28 Oct 2024 16:47:54 +0100 Received: by alpha.franken.de (Postfix, from userid 1000) id 0B333C0161; Mon, 28 Oct 2024 16:47:30 +0100 (CET) Date: Mon, 28 Oct 2024 16:47:30 +0100 From: Thomas Bogendoerfer To: Daniel Lezcano Cc: Aleksandar Rikalo , Chao-ying Fu , Geert Uytterhoeven , Greg Ungerer , Hauke Mehrtens , Ilya Lipnitskiy , Jiaxun Yang , linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, Marc Zyngier , Paul Burton , Peter Zijlstra , Serge Semin , Thomas Gleixner , Tiezhu Yang , Gregory CLEMENT Subject: Re: [PATCH v7 05/12] clocksource: mips-gic-timer: Always use cluster 0 counter as clocksource Message-ID: References: <20241019071037.145314-1-arikalo@gmail.com> <20241019071037.145314-6-arikalo@gmail.com> <3c98775b-b61b-478f-838e-59f8e1cf8aed@linaro.org> 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 Mon, Oct 28, 2024 at 04:22:55PM +0100, Daniel Lezcano wrote: > On 28/10/2024 16:15, Thomas Bogendoerfer wrote: > > On Mon, Oct 28, 2024 at 03:54:48PM +0100, Daniel Lezcano wrote: > > > On 19/10/2024 09:10, Aleksandar Rikalo wrote: > > > > From: Paul Burton > > > > > > > > In a multi-cluster MIPS system, there are multiple GICs - one in each > > > > cluster - each of which has its independent counter. The counters in > > > > each GIC are not synchronized in any way, so they can drift relative > > > > to one another through the lifetime of the system. This is problematic > > > > for a clock source which ought to be global. > > > > > > > > Avoid problems by always accessing cluster 0's counter, using > > > > cross-cluster register access. This adds overhead so it is applied only > > > > on multi-cluster systems. > > > > > > > > Signed-off-by: Paul Burton > > > > Signed-off-by: Chao-ying Fu > > > > Signed-off-by: Dragan Mladjenovic > > > > Signed-off-by: Aleksandar Rikalo > > > > Tested-by: Serge Semin > > > > --- > > > > > > May I take this patch through the clocksource tree ? > > > > sure, should be the best option. > > Ok, thanks > > Can you add your tag ? it's only touching drivers/clocksource, but if you want Acked-by: Thomas Bogendoerfer -- Crap can work. Given enough thrust pigs will fly, but it's not necessarily a good idea. [ RFC1925, 2.3 ]