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,URIBL_BLOCKED,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 E957CC433DB for ; Tue, 2 Mar 2021 15:29:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A2C3864F2F for ; Tue, 2 Mar 2021 15:29:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1578804AbhCBP1S (ORCPT ); Tue, 2 Mar 2021 10:27:18 -0500 Received: from mail.kernel.org ([198.145.29.99]:60564 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351029AbhCBNDQ (ORCPT ); Tue, 2 Mar 2021 08:03:16 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 1F86D64FBC; Tue, 2 Mar 2021 11:59:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1614686350; bh=MmzIUQi4WSmgCuB9jJMRQiChPqM8XxCBhyI/NSHeqgc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iuc4JNiM+dibxg1btPq8fH6EQ7cIN+XvmY/Cmo89bBGbU5TFIvVVkuaFCpP8HBrSc hmZ2LtULzmq+CP8vmaSZTNz6MM8Ij+nkjkNp5sEIum3WY02TZHTNXeHF7SJpiKwDwF GeMtD1mSV0CSovNQXBljuwv8fK70inGMVYHpBhRWvmFwLpbfn65dYR2dtju8z4f0CK KMqGxxlSPCsMH6jjlsK/b0+IP0QnWIAGqCD8OguqohQg3T8wRyHA8g+VAcM4VsmJgX IRXXCo1agIp2RMXXD60cX49W/cgSKtSNezrBeGBAZsIWVbsKwTl4NYB+vMvi8ni2SZ pS0u357s4+aOA== 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 4.14 05/13] powerpc/perf: Record counter overflow always if SAMPLE_IP is unset Date: Tue, 2 Mar 2021 06:58:55 -0500 Message-Id: <20210302115903.63458-5-sashal@kernel.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210302115903.63458-1-sashal@kernel.org> References: <20210302115903.63458-1-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: linux-kernel@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 56f16c803590..2669847434b8 100644 --- a/arch/powerpc/perf/core-book3s.c +++ b/arch/powerpc/perf/core-book3s.c @@ -2055,7 +2055,17 @@ 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) @@ -2073,9 +2083,10 @@ 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