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 72FD1C83F34 for ; Thu, 17 Jul 2025 15:31:40 +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:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=TPkUx24Vo2aYicjoHowpupWEI4Zc1uKXg31kPYaUYQY=; b=1X0hPhXiASry/Z66plMGREXQku 4iL4ymJzCrdFRqpv4BXhNOqAXTNhza8hh37x7zJlI+70usR8TOTqGdE2Kqr/0rPpvuRnE9K6To0s3 WE3AicczxyZHXZl16f0RZhxSQ9MpOYqm1kzYJg31oDKX2q47zv1ecE+QgUuSdNjcM0Ch0NqdWgifH offuEI4AlJzosAyu+EeICiLDdsvZ+EVvwGvkxtfe5t/yP+OYVowtajDm2ip6mHJNo2JIkhJajl3wZ OkEXBbyD0vDnhhNgQEEs4QppqaAC32QN2imm6bP3/dzhIBRs6Psox5C+AnqXyjuqIM1OtARsjUBJa ZbL6PHMA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1ucQa6-0000000AVrT-1IJ2; Thu, 17 Jul 2025 15:31:34 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1ucPcd-0000000ANep-2KGs for linux-arm-kernel@lists.infradead.org; Thu, 17 Jul 2025 14:30:09 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id E1CA55C077F; Thu, 17 Jul 2025 14:30:06 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D731BC4CEE3; Thu, 17 Jul 2025 14:30:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1752762606; bh=0WzZkjhX8wGliBownxT0mAsfFW9ZWAVlF7kWj0BjBVw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=MWQb4Zewxy9SCl7yC+evEFFUBAjupypasKkfzhneL8szoKWz2KRwNYzyViM9Gwi7G gsK/ejuYavl/DjQlM5v/1g6ixBSaS14caJ3bsr0qFvRfgsCb5cEKEiLmkr6O0rG9wj 7QsS9I7ixvB0R+wy6EesUn6EQ/imsCIN4d6lmMUeYz4A2aKWmwZHX3k/0gs7b/LdSi DbH25ErAqiaqbcBEBoV5qGVDcoMsEucJgaVcYCD4utMxqd8zz7JoHzTUtTBU53V9b7 gx8OWNCAf5tTG/Hz09S5WFxIc//1QUdjdaa2TGK/iuyA7uV8v4BZWf6OnoBCodtZto YayyHUOrxqkMA== Date: Thu, 17 Jul 2025 15:29:59 +0100 From: Will Deacon To: James Clark Cc: Catalin Marinas , Mark Rutland , Jonathan Corbet , Marc Zyngier , Oliver Upton , Joey Gouly , Suzuki K Poulose , Zenghui Yu , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , leo.yan@arm.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-doc@vger.kernel.org, kvmarm@lists.linux.dev Subject: Re: [PATCH v3 07/10] perf: arm_spe: Add support for filtering on data source Message-ID: References: <20250605-james-perf-feat_spe_eft-v3-0-71b0c9f98093@linaro.org> <20250605-james-perf-feat_spe_eft-v3-7-71b0c9f98093@linaro.org> <7f51d4f9-7e08-49b5-ab43-8bc765bb2ca8@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7f51d4f9-7e08-49b5-ab43-8bc765bb2ca8@linaro.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250717_073007_676502_4CFDE9D6 X-CRM114-Status: GOOD ( 22.48 ) 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 Tue, Jul 15, 2025 at 02:04:18PM +0100, James Clark wrote: > On 14/07/2025 3:04 pm, Will Deacon wrote: > > On Thu, Jun 05, 2025 at 11:49:05AM +0100, James Clark wrote: > > > @@ -406,6 +416,9 @@ static u64 arm_spe_event_to_pmsfcr(struct perf_event *event) > > > if (ATTR_CFG_GET_FLD(attr, inv_event_filter)) > > > reg |= PMSFCR_EL1_FnE; > > > + if (ATTR_CFG_GET_FLD(attr, data_src_filter)) > > > + reg |= PMSFCR_EL1_FDS; > > > > Is the polarity correct here? The description of PMSDSFR_EL1.S suggests > > that setting bits to 1 _excludes_ the FDS filtering. > > > > Setting filter bits to 1 means that samples matching are included. Setting > bits to 0 means that they are excluded. And PMSFCR_EL1.FDS enables filtering > as a whole, so if the user sets any filter bit to 1 we want to enable > filtering: > > PMSDSFR_EL1.S > > 0b0 If PMSFCR_EL1.FDS is 1, do not record load operations that have > bits [5:0] of the Data Source packet set to . > > 0b1 Load operations with Data Source are unaffected by > PMSFCR_EL1.FDS. > > I think it's all the right way around and it ends up being the same as the > other filters in SPE. Because we're using any bit being set to enable the > filtering, the only thing you can't do is enable filtering with a 0 filter, > but I didn't think that was useful. See the previous discussion on this > here: > https://lore.kernel.org/all/5752f039-51c1-4452-b5df-03ff06da7be3@linaro.org/ > > Reading the "Data source filtering" section in the docs change at the end > might help too. Sorry, but I still don't get it :/ afaict, if any of the bits in 'data_src_filter' are _zero_ then we should set PMSFCR_EL1.FDS. That also means that a mask of zero means all loads are filtered, which is what the architecture says and is what we should provide to userspace. Will