From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 695ACEE3F3F for ; Tue, 12 Sep 2023 22:55:18 +0000 (UTC) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=ellerman.id.au header.i=@ellerman.id.au header.a=rsa-sha256 header.s=201909 header.b=NNkhvJJS; dkim-atps=neutral Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4Rlf790KVrz3fgH for ; Wed, 13 Sep 2023 08:55:17 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=ellerman.id.au header.i=@ellerman.id.au header.a=rsa-sha256 header.s=201909 header.b=NNkhvJJS; dkim-atps=neutral Received: from gandalf.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4Rlf6B694cz3fY8 for ; Wed, 13 Sep 2023 08:54:26 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ellerman.id.au; s=201909; t=1694559263; bh=9qFhBwApOtxbCRkss+cXTdVSRxiqaNw6Cm3OsXpblk0=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=NNkhvJJSuTAjyxdHn9KL8t+JxECMLmlaD2DyhL7HZu/5W/LGNlBPB8kYup011jINm x0z1ik7md75tNC7W51XDMILuvot3hiewacJvknMqa4Kb3ws4ihsRiy5FWi/6TpnaeO IKW/iy47r3GWyUzBomcanUO0KDpA14BHCvGCNEVnwAgZMcumbJmTyztECe9ufcV6gd mvD/UzUNzMjSvoZ5nUyRT5T0JqGLIClE/OOzb5pEgOgglWMK1FWT5ZdavqwkXiLJrv RwrQJAKcsmpfibrAOaxB7EPC4oavOVn9CVfCu3xiFxgz4hCwgjRMdR5zpWiWxm5pRT go2se/utZvTYw== Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4Rlf672wVTz4xQj; Wed, 13 Sep 2023 08:54:23 +1000 (AEST) From: Michael Ellerman To: Aboorva Devarajan , aboorvad@linux.vnet.ibm.com, npiggin@gmail.com, rmclure@linux.ibm.com, arnd@arndb.de, joel@jms.id.au, shuah@kernel.org, linux-kselftest@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, pratik.r.sampat@gmail.com Subject: Re: [RFC v3 1/2] powerpc/cpuidle: cpuidle wakeup latency based on IPI and timer events In-Reply-To: <20230911053620.87973-2-aboorvad@linux.vnet.ibm.com> References: <20230911053620.87973-1-aboorvad@linux.vnet.ibm.com> <20230911053620.87973-2-aboorvad@linux.vnet.ibm.com> Date: Wed, 13 Sep 2023 08:54:15 +1000 Message-ID: <87a5trvw88.fsf@mail.lhotse> MIME-Version: 1.0 Content-Type: text/plain X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: sshegde@linux.vnet.ibm.com, srikar@linux.vnet.ibm.com Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Aboorva Devarajan writes: > From: Pratik R. Sampat > > Introduce a mechanism to fire directed IPIs from a source CPU to a > specified target CPU and measure the time incurred on waking up the > target CPU in response. > > Also, introduce a mechanism to queue a hrtimer on a specified CPU and > subsequently measure the time taken to wakeup the CPU. > > Define a simple debugfs interface that allows for adjusting the > settings to trigger IPI and timer events on a designated CPU, and to > observe the resulting cpuidle wakeup latencies. > > Reviewed-by: Srikar Dronamraju > Signed-off-by: Pratik R. Sampat > Signed-off-by: Aboorva Devarajan > --- > arch/powerpc/Kconfig.debug | 10 ++ > arch/powerpc/kernel/Makefile | 1 + > arch/powerpc/kernel/test_cpuidle_latency.c | 154 +++++++++++++++++++++ I don't see anything here that's powerpc specific? Which makes me wonder 1) could this be done with some existing generic mechanism?, and 2) if not can this test code be made generic. At the very least this should be Cc'ed to the cpuidle lists & maintainers given it's a test for cpuidle latency :) cheers