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 X-Spam-Level: X-Spam-Status: No, score=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 58D05C4332D for ; Wed, 3 Mar 2021 00:46:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2E55964FC5 for ; Wed, 3 Mar 2021 00:46:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238717AbhCCA2Y (ORCPT ); Tue, 2 Mar 2021 19:28:24 -0500 Received: from mail.kernel.org ([198.145.29.99]:50438 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1383881AbhCBMcT (ORCPT ); Tue, 2 Mar 2021 07:32:19 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2890C64FCF; Tue, 2 Mar 2021 11:59:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1614686380; bh=glpC+gZtIoGE6mio5K8dAKMeg1fOZFQX0piH/UGVogQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=f4xsXUxr7khE8NYgN05N2QjwgZSdUOs7nVj+OLp4B0v78wSt4yHyldv48YiB9H0Te qm/Ly+jiJyLWKrxm11U8S9SzXH8tI1tnNZiRr/PCAytSf+Ck5v6yEvQr+66ZyLuo9U /GLpfLXCRw0ocbNYmQ9RrDlu/dOv4fJmnDeoOFMHAUgY3C1mLBCeB18AfW4Dly1Dck 5MdZpp+Kvy1cUSapMxiGidiiOi70sBU+oJ6NhoCuYIQfyN07ezGbOPzyy9iGTSnLG2 rgEdlEy2+/yyucjhcnV4uPSMRX/758mDruM0SHDL55MKiAKpE8fac2FrRcX4xgmWPU pzlUxBvslHigA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Athira Rajeev , Michael Ellerman , Sasha Levin , linuxppc-dev@lists.ozlabs.org Subject: [PATCH AUTOSEL 4.4 3/8] powerpc/perf: Record counter overflow always if SAMPLE_IP is unset Date: Tue, 2 Mar 2021 06:59:30 -0500 Message-Id: <20210302115935.63777-3-sashal@kernel.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210302115935.63777-1-sashal@kernel.org> References: <20210302115935.63777-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Athira Rajeev [ Upstream commit d137845c973147a22622cc76c7b0bc16f6206323 ] While sampling for marked events, currently we record the sample only if the SIAR valid bit of Sampled Instruction Event Register (SIER) is set. SIAR_VALID bit is used for fetching the instruction address from Sampled Instruction Address Register(SIAR). But there are some usecases, where the user is interested only in the PMU stats at each counter overflow and the exact IP of the overflow event is not required. Dropping SIAR invalid samples will fail to record some of the counter overflows in such cases. Example of such usecase is dumping the PMU stats (event counts) after some regular amount of instructions/events from the userspace (ex: via ptrace). Here counter overflow is indicated to userspace via signal handler, and captured by monitoring and enabling I/O signaling on the event file descriptor. In these cases, we expect to get sample/overflow indication after each specified sample_period. Perf event attribute will not have PERF_SAMPLE_IP set in the sample_type if exact IP of the overflow event is not requested. So while profiling if SAMPLE_IP is not set, just record the counter overflow irrespective of SIAR_VALID check. Suggested-by: Michael Ellerman Signed-off-by: Athira Rajeev [mpe: Reflow comment and if formatting] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/1612516492-1428-1-git-send-email-atrajeev@linux.vnet.ibm.com Signed-off-by: Sasha Levin --- arch/powerpc/perf/core-book3s.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) diff --git a/arch/powerpc/perf/core-book3s.c b/arch/powerpc/perf/core-book3s.c index e593e7f856ed..7a80e1cff6e2 100644 --- a/arch/powerpc/perf/core-book3s.c +++ b/arch/powerpc/perf/core-book3s.c @@ -2008,7 +2008,17 @@ static void record_and_restart(struct perf_event *event, unsigned long val, left += period; if (left <= 0) left = period; - record = siar_valid(regs); + + /* + * If address is not requested in the sample via + * PERF_SAMPLE_IP, just record that sample irrespective + * of SIAR valid check. + */ + if (event->attr.sample_type & PERF_SAMPLE_IP) + record = siar_valid(regs); + else + record = 1; + event->hw.last_period = event->hw.sample_period; } if (left < 0x80000000LL) @@ -2026,9 +2036,10 @@ static void record_and_restart(struct perf_event *event, unsigned long val, * MMCR2. Check attr.exclude_kernel and address to drop the sample in * these cases. */ - if (event->attr.exclude_kernel && record) - if (is_kernel_addr(mfspr(SPRN_SIAR))) - record = 0; + if (event->attr.exclude_kernel && + (event->attr.sample_type & PERF_SAMPLE_IP) && + is_kernel_addr(mfspr(SPRN_SIAR))) + record = 0; /* * Finally record data if requested. -- 2.30.1