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 6C11C2A1BB; Thu, 24 Jul 2025 05:16:17 +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=1753334177; cv=none; b=LsPMZ0+Ar6+wqLkwd46Xd396+nxJuu+s1LyP09SOY1mwRQCq9naDywIy/mRiUvUGJiFWhH4EulCjFtHt67JH2a7BJQV+OUK3yRUfYiZnhu1dzh4SslVTr8hnpADhzSdfo6f0g5Dev+zOI0ME/3CcX9TEB6g8H7PbOZ4YEYiTMkc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753334177; c=relaxed/simple; bh=ChjVuI92grVv1Wb2zdKvfkGA/KdPS2ntIBxgSs2cy58=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=oVWbUZAgzcT2bE+xkXEsvaFMoX8KtfVoz+GnPztHDBOas4ZhBg5fSX62mdnm3ZcRnPBO9Yck+iPw3GCgQBMSCS99g1L0fL2q42nXq0FCtOL0t5PAI96i3HF/CVVYBx3kRw6zcxY+QllT8n8rzZ1ZG4aq/mQzkV2qlByHWF2uYz8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=aDf7fPKv; 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="aDf7fPKv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3550AC4CEED; Thu, 24 Jul 2025 05:16:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1753334177; bh=ChjVuI92grVv1Wb2zdKvfkGA/KdPS2ntIBxgSs2cy58=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=aDf7fPKvrbph1QdRpdmMP1z3QCXzHu++/Y+tNqfUMDcJkq+/L4GysacmuFXgk22jc 75N8KslaSQq6uIm3+in+iMrdqLIvw/VmhZtRM2ceSHB38C34EpYGPXjg4yk7yRGNEk u7OaKXHzlJ3uDkLp1MyYQQCwNzrZwzGq40UZjQfWdLFBQtQeeLcdSEyPF10nmLF66Z MARPPCh2EdnesPU4JwD7wjM6DDnc7WvY68KW7o/XvCKKBAqRRX6xSBdwXsQ1J5NLmq q7qpZQ1VqnlxyLLFU3uQHkWuSXl3rAkwMYvTXcahJN6NBQbO9qJtN72FaJsksOviPs U/1ZSxMOu5vfA== Date: Thu, 24 Jul 2025 07:16:12 +0200 From: Ingo Molnar To: linux-kernel@vger.kernel.org, Thomas Gleixner , Daniel Lezcano Cc: linux-tip-commits@vger.kernel.org, Donghoon Yu , Youngmin Nam , John Stultz , Will McVicker , Daniel Lezcano , x86@kernel.org Subject: Re: [tip: timers/clocksource] clocksource/drivers/exynos_mct: Don't register as a sched_clock on arm64 Message-ID: References: <20250620181719.1399856-3-willmcvicker@google.com> <175325504976.1420.2666973232153470630.tip-bot2@tip-bot2> 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: <175325504976.1420.2666973232153470630.tip-bot2@tip-bot2> * tip-bot2 for Will McVicker wrote: > The following commit has been merged into the timers/clocksource branch of tip: > > Commit-ID: 394b981382e6198363cf513f6eb6be4c55b22e44 > Gitweb: https://git.kernel.org/tip/394b981382e6198363cf513f6eb6be4c55b22e44 > Author: Will McVicker > AuthorDate: Fri, 20 Jun 2025 11:17:05 -07:00 > Committer: Daniel Lezcano > CommitterDate: Tue, 15 Jul 2025 13:00:50 +02:00 > > clocksource/drivers/exynos_mct: Don't register as a sched_clock on arm64 > > The MCT register is unfortunately very slow to access, but importantly > does not halt in the c2 idle state. So for ARM64, we can improve > performance by not registering the MCT for sched_clock, allowing the > system to use the faster ARM architected timer for sched_clock instead. > > The MCT is still registered as a clocksource, and a clockevent in order > to be a wakeup source for the arch_timer to exit the "c2" idle state. > > Since ARM32 SoCs don't have an architected timer, the MCT must continue > to be used for sched_clock. Detailed discussion on this topic can be > found at [1]. > > [1] https://lore.kernel.org/linux-samsung-soc/1400188079-21832-1-git-send-email-chirantan@chromium.org/ > > [Original commit from https://android.googlesource.com/kernel/gs/+/630817f7080e92c5e0216095ff52f6eb8dd00727 > > Signed-off-by: Donghoon Yu > Signed-off-by: Youngmin Nam > Reviewed-by: Youngmin Nam > Acked-by: John Stultz > Tested-by: Youngmin Nam > Signed-off-by: Will McVicker > Link: https://lore.kernel.org/r/20250620181719.1399856-3-willmcvicker@google.com > Signed-off-by: Daniel Lezcano The whole SOB chain of this commit is messy and has several serious problems: 1) This commit has misattributed authorship: the first SOB is: Signed-off-by: Donghoon Yu but the Author field is not Donghoon Yu: Author: Will McVicker 2) The Reviewed-by tag is misapplied: > Signed-off-by: Youngmin Nam > Reviewed-by: Youngmin Nam When someone passes along a patch, it's implicit that they have reviewed it. 3) There's also a stray Tested-by tag by one of the SOB entries: > Signed-off-by: Youngmin Nam > Reviewed-by: Youngmin Nam > Tested-by: Youngmin Nam When someone passes along a patch, it's implicit that they not only have reviewed the patch, but have also tested it to a certain extent ... 4) Why is the 'Link' tag just in the middle of the SOB chain, instead at the end of it? Presumably this is the proper SOB chain: > Author: Donghoon Yu > Signed-off-by: Donghoon Yu > Signed-off-by: Youngmin Nam > Signed-off-by: Will McVicker > Signed-off-by: Daniel Lezcano > Acked-by: John Stultz > Link: https://lore.kernel.org/r/20250620181719.1399856-3-willmcvicker@google.com Correct? Thanks, Ingo