From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 8AA0313D891; Mon, 23 Feb 2026 09:15:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771838154; cv=none; b=UrG//AVgasHwMznC9GOOTzJMXDGzSVJM2WbsZLS/hyvGP8nMOCq1xR/vMvgyqKHcYU7j0XE80PdIYOSgWlEs58M79I+l/2ngOIrT7Kqs7wlfAokMAIcrFXIZOJqbmYpzSFEbLiKggaTRjEV5Yr0Mnu3FQwXTXpmr7stmYpqsRu0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771838154; c=relaxed/simple; bh=6udqOftI4y08g8IexuZmqUZ6jWyjJMTADJKWbvH4DqY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=WrygEw1yE0KVG6oBU34atxaAlvCrTE2pJm60IQk2DUbTtC9nWh6BXkYjeEK7RsQMqFa93/jx41aiGcNhqDGqXqEjaokebuAGTrsY/c1RCrmWNMsJ7YOlKVkQZwwKe9HywBg24LyajPGsOjGYcZJV4Q6xvPTYEsqkLg/QifFvM/g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 04162339; Mon, 23 Feb 2026 01:15:44 -0800 (PST) Received: from localhost (e132581.arm.com [10.1.196.87]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id D54243F62B; Mon, 23 Feb 2026 01:15:49 -0800 (PST) Date: Mon, 23 Feb 2026 09:15:47 +0000 From: Leo Yan To: Jisheng Zhang Cc: Catalin Marinas , Will Deacon , Arnd Bergmann , Thomas Gleixner , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Guo Ren , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-riscv@lists.infradead.org, linux-csky@vger.kernel.org Subject: Re: [PATCH 3/3] arm64: use runtime constant to optimize handle_arch_irq access Message-ID: <20260223091547.GJ136967@e132581.arm.com> References: <20260220090922.1506-1-jszhang@kernel.org> <20260220090922.1506-4-jszhang@kernel.org> <20260220123414.GF136967@e132581.arm.com> <20260220164738.GH136967@e132581.arm.com> Precedence: bulk X-Mailing-List: linux-csky@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 Sat, Feb 21, 2026 at 08:14:17AM +0800, Jisheng Zhang wrote: [...] > On Fri, Feb 20, 2026 at 04:47:38PM +0000, Leo Yan wrote: > > On Fri, Feb 20, 2026 at 09:34:14PM +0800, Jisheng Zhang wrote: > > > > [...] > > > > > > > Run 3 iterations, and measures three metrics (messaging/pipe/seccomp) > > > > > and results in seconds. Less is better. > > > > > > > > > > +---------------------+--------+--------+--------+--------+ > > > > > |Without change | run1 | run2 | run3 | avg | > > > > > +---------------------+--------+--------+--------+--------+ > > > > > |messaging (sec) | 4.546 | 4.508 | 4.591 | 4.548 | > > > > > |pipe (sec) | 24.258 | 24.224 | 24.017 | 24.166 | > > > > > |seccomp-notify (sec) | 48.393 | 48.457 | 48.232 | 48.361 | > > > > > +---------------------+--------+--------+--------+--------+ > > > > > > > > > > +---------------------+--------+--------+--------+--------+--------+ > > > > > |With change | run1 | run2 | run3 | avg | diff | > > > > > +---------------------+--------+--------+--------+--------+--------+ > > > > > |messaging (sec) | 4.493 | 4.523 | 4.556 | 4.524 | +0.52% | > > > > > |pipe (sec) | 23.159 | 23.702 | 28.649 | 25.170 | -4.15% | > > > > > > > > If you check the result, this result variance is abnormal, it means > > > > your OS is noiser. > > > > > > BTW: if you remove the abnormal run3 result, you'll find that the > > > benchmark is improved by ~3.5% on CA73: > > > (23.159 + 23.702) / 2 = 23.43 > > > (24.258 + 24.224) / 2 = 24.24 > > > (24.24 - 23.43)*100 / 23.43 = ~3.5 > > > > TBH, I don't think we should subjectively select data. But I agree a > > The precondition of this is testing the benchmark properly. And I just > tried perf bench sched in noisy OS, I didn't get the similar abnormal > variance as you got, so I think your run3 result was CA53's result. > This isn't an apple-to-apple comparison. Not true. As said, I tested on CA73. I should say explicitly that I have hotplugged off CA53 CPUs and run test only on CA73 CPUs. > If possible, could you plz test after forcing CA53 offline or test on > non big.little platform. Anyway, I will test CA73 next week too. > > > clean test env is important to avoid noise, and I also agree that the > > current results already show positive signals. > > > > Thanks, > > Leo