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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 0614CCA5FF0 for ; Mon, 5 Oct 2026 13:15:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=2wzxu0EWI2kaKwB7R1TPSDkmRDLOU/vc/6W9NX0gtYU=; b=RitUTZGdn6S3/pfp2EyYkdud4Y 83iCMIy9yxOtAsZF6M4PB9oRi2pCImDvdMmquinFG1IAU7q6oQoX9EHwLyTBckD+U2iLK0DWsnse9 k+DSaIhEJnbLD8cQsN0TBEhMPba7BxF4/RX0e7IsaAoUqjhvtTpqATZAE0hhIseXeQSHroPhEioVV t+gUTPmPMuZD9v5Nh1pYewyBEtl2Udg3bnOuEzCeFyDiJP+HG2n5NQQCjK2QnLu/fvojobe1iJ4nT YfHkQOOTpbc/psJATdo+3ylXX0v9WLgnEM6omUgy1udOxboQCF2iitzWp9uQpkTtNXF075hheFXyb 0J4UW+yQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xDiXa-0000000GVKM-2cc3; Mon, 05 Oct 2026 13:15:39 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1xDiXX-0000000GVJY-4A8N for linux-arm-kernel@lists.infradead.org; Mon, 05 Oct 2026 13:15:37 +0000 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 6C187152B; Mon, 5 Oct 2026 06:15:31 -0700 (PDT) Received: from [10.2.212.23] (e121345-lin.cambridge.arm.com [10.2.212.23]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 43B0C3F86F; Mon, 5 Oct 2026 06:15:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1791206134; bh=m3tmSH0+leL7BS79iE/YdCgWfzPU9HDRqYcmSoRJD60=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=KIoe/8CVD+wIe5QvHf9R7AMxlQqGiVNz0V7h5QPw/ZHk2OZsH79wmWEzt9Y1FfqzX ZwsAJ3IoJNBq2cwafU4UjpJMqKW6zdpFuJFYIwSYCjQwsWSP+CbwK11PYGo8zrCCQa FZMAltM8TzJtX3bWD+Hw3zF3f5wPv7kbo7+WdpbY= Message-ID: <426110f0-0ef4-4f15-b68f-103a863df3aa@arm.com> Date: Mon, 5 Oct 2026 14:15:32 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3] perf: Add Arm Bus Monitor Unit driver To: Will Deacon Cc: mark.rutland@arm.com, linux-perf-users@vger.kernel.org, linux-arm-kernel@lists.infradead.org References: From: Robin Murphy Content-Language: en-GB In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261005_061536_085879_02236E9C X-CRM114-Status: GOOD ( 13.20 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 04/10/2026 11:10 pm, Will Deacon wrote: > On Thu, Sep 17, 2026 at 02:47:12PM +0100, Robin Murphy wrote: >> Arm's Bus Monitor Unit is a low-level performance analysis tool for >> matching and counting transactions at interconnect interfaces. Each >> BMU consists of a number of "interface monitoring units", with some >> global controls to synchronise them and so permit accurate calculation >> of cross-interface metrics. Each IMU contains, among other things, its >> own PMU largely based on the CoreSight PMU architecture, but with some >> functional incompatibilities due to the nature of how much per-event >> filtering needs to be crammed in to categorise AXI/CHI transactions at >> the protocol level. As such it gets an honorary home in arm_cspmu/ in >> order to share the common register definitions, but for simplicity does >> not try to bend the functional abstraction to fit. >> >> Signed-off-by: Robin Murphy >> >> --- >> v3: >> - Couple of inconsequential tweaks to shut Sashiko up about things >> that would never actually happen anyway >> - Drop unneeded DT patches that I can't be bothered to fix right now > > Please can you take a look at the Sashiko comments on this one? I did start writing a reply at the time, but it was getting so sarcastic that even I thought better of sending it... In (polite) summary: 1 - Gibberish 2 - Yes if firmware blatantly mis-describes the hardware then Linux may not work properly. Whoop de do. 3 - Yeah so? 4 - Pants-on-head gibberish, but the second part about COMPILE_TEST is fair (an oversight from ripping out the DT support) - fix is already in -next via the ACPI tree[1] 5 - Yeah so? 6,7 - Yes, welcome to perf... Cheers, Robin. [1] https://lore.kernel.org/all/CAJZ5v0g4k6FhyQMypkRyVJMkSBUsmeuetJuxRA826PcA7Mo5Hg@mail.gmail.com/