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 93DC1C28EBD for ; Wed, 3 Mar 2021 00:21:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7029064F44 for ; Wed, 3 Mar 2021 00:21:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236757AbhCCAQL (ORCPT ); Tue, 2 Mar 2021 19:16:11 -0500 Received: from mail.kernel.org ([198.145.29.99]:44812 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1443551AbhCBMLd (ORCPT ); Tue, 2 Mar 2021 07:11:33 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8C50464F5D; Tue, 2 Mar 2021 11:57:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1614686228; bh=Zu8fV2dqIQMQ4wUfffc4Cb70bWD8fWMChTJTi7DlsNI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DTdS7QBRGIHZQTnnei5/bEYEevYMcD1efdVMQQYUa7TcOUn7YTY3IkEcc39YkySyY TE9FNDi4/tnQn/6C/v+47ctpVBlsVy48nyN1pXzcYYp+l3lRcdDCenCbvcAlHFiihu Wbwp6K08sOnJ6+SHteKC8H1PABnQEDLtwUvLidn+BXFEDIP4cOFPPZIN1Vb5EnPKxn /H7Qyd98upS4065p0twMPIcHe2F3a3Y51fHWMzN6mnre1Z9qVHIlEG70FDmwmhqbCl kDgmWmoLhtbVyXoUIujJ6au3cIF45fPFN24oyL/7JUQ4yOqyp3iiftNSFAOCWSftGB dgA8xi9q6uMxA== 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 5.10 17/47] powerpc/perf: Record counter overflow always if SAMPLE_IP is unset Date: Tue, 2 Mar 2021 06:56:16 -0500 Message-Id: <20210302115646.62291-17-sashal@kernel.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210302115646.62291-1-sashal@kernel.org> References: <20210302115646.62291-1-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 43599e671d38..d84ab867b986 100644 --- a/arch/powerpc/perf/core-book3s.c +++ b/arch/powerpc/perf/core-book3s.c @@ -2112,7 +2112,17 @@ 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) @@ -2130,9 +2140,10 @@ 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