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 6F16D395D99; Wed, 25 Feb 2026 14:58:36 +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=1772031516; cv=none; b=WgxCqZ+UTb30C3V4M+MJSSaeaFb2/QDdcKxtaCfoDF8YTJdRVCwBcYOJ+0xVg4C0d38yxi5aKoSfbWHQoBvQn/mSaYTuvPSPCdQaEVk/AZsMzDjcHOYX32zWbaYMsJYlFsn+tazbuvjHiw9wDeGPQH1nuB3tMirWdwr0qqfbgH4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772031516; c=relaxed/simple; bh=DKswOemgE0o8dLAbtbgTdWvG4rdX6n55NSS0972JIdc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=hVjEExkC1Kdkl35Vbei9SgBXHDAXV9b8s/mGYx8rV8Bp3Mw2xtQwN0z/qg0SxmeG+3pHbDMNC6eWOHHTASsV+mKSkJ+mpvUQLvbua2u+mB7C6avEhm39yZ7nlDeL0NfWJB1gNsJA0dVjBRB4e35ZcG6fnx2HwmxHLeh1Y2oRzrs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Mdh6iujj; 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="Mdh6iujj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 910B6C116D0; Wed, 25 Feb 2026 14:58:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772031516; bh=DKswOemgE0o8dLAbtbgTdWvG4rdX6n55NSS0972JIdc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Mdh6iujjSWp6SFz+JwLy4nalaRpHoytaT2mXrTErJdY8ripQ/GKKYsH1b4yAf+HN4 bt2suB/55pPPBWFpqHeD5Wf39lqMh8j/eCfpQ/7ZSOTdklaPGnXI+6N/ciFXt5w7l6 K+AkIiooofhvA2kywZtHdb++EyS59f+F8KnRSR+E2QCR71eqiPfOz0zxuodScZsQkH wYrCJuQhJlMi/x81lK+QlxaMf2EwoNJ8O50o9wHLMBYStJitsqpCEgdFsRfVcbwA/O 5uR2Pq84gRkLCyKcI0lNk99ypfPbGi9rQ6KJc5K/xZf00J+9lmkqkfdjqbP46f6P3S IsjdrQZRFnTNA== Date: Wed, 25 Feb 2026 22:40:00 +0800 From: Jisheng Zhang To: Leo Yan 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: References: <20260220090922.1506-1-jszhang@kernel.org> <20260220090922.1506-4-jszhang@kernel.org> <20260220123414.GF136967@e132581.arm.com> <20260220164738.GH136967@e132581.arm.com> <20260223091547.GJ136967@e132581.arm.com> 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=utf-8 Content-Disposition: inline In-Reply-To: <20260223091547.GJ136967@e132581.arm.com> On Mon, Feb 23, 2026 at 09:15:47AM +0000, Leo Yan wrote: > 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. I tested on quad CA73 platform, I can reproduce the abnormal variance as you got. This means the series may not alway improve performance as I expected for *all* CPUs. So I'd like to drop it now. > > > 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