From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CD5211422D4 for ; Thu, 5 Sep 2024 03:10:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725505828; cv=none; b=aTLI0zKa92SfT37NaU+gXkdxnl8zYeAhaRgcqsa4pVrGBKF88e5N8FfF3IPbRb9d5hpEALQN00fp8fZy8L1w+7xwkOE6DX7qI6yCmtb+8o2EoVR+BdhvegOSS010pi62z7Occi4she4zaXzOgv0ivPnHQvLUd/2Rku+TVGNkD1o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725505828; c=relaxed/simple; bh=8U/+lWF0Wmx6pUU6P6UrrUMykJO3VDzldoqy1DB1r8k=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=BgOW5y4xe9ijFQprQxOJqDEKhlneaZ0MmY292TcT//jN122hUlT7hNTNAi03ja8kAQcymLMzMwfUbrpEtP7/o14j9tE7DUX7NemE76bFN0De5W2v91eRcc9s1D/A1BOZkt06P2g7xcCqRLy49MyUawcKJ7VPB8dI5vyTp/QN1Oo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=hTUzM9ro; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="hTUzM9ro" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EDF86C4CEC2; Thu, 5 Sep 2024 03:10:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1725505828; bh=8U/+lWF0Wmx6pUU6P6UrrUMykJO3VDzldoqy1DB1r8k=; h=From:To:Cc:Subject:Date:From; b=hTUzM9romQOYOJNPRHH3o5DZshnE6uXFltI/o2FEen3LhCqxj8Sjs2aaJFuJk/Urt C6RWFczlNV/USikuFP3CefW+qIExchEbmlfF9HTv+i6EfVzKtK3QcbzicNw3qaAEXg qvbDykq8m4vPcr5uvRY6Ry1FumwLICeqW1D04dDFO6d72lF+STQ4dQuJGafJZQneub 8BXEVPIa8KIfgOsoUcVKWkKwkAivQ1uUfbawBCX3bGyzVFHOizGxMt6+mtBOO4CGDB hWAlhj55WpSU+0bRdSN+Rue5ddh4F/oVQ56eZbx9/eHz5+PCHkdgMt9ji7Sx++qEi3 xnQLUJHnLfdcg== From: Namhyung Kim To: Peter Zijlstra , Ingo Molnar Cc: Kan Liang , Mark Rutland , Alexander Shishkin , Arnaldo Carvalho de Melo , LKML , Stephane Eranian , Ravi Bangoria Subject: [RFC/PATCH 0/5] perf: Relax privilege restriction on AMD IBS (v3) Date: Wed, 4 Sep 2024 20:10:22 -0700 Message-ID: <20240905031027.2567913-1-namhyung@kernel.org> X-Mailer: git-send-email 2.46.0.469.g59c65b2a67-goog Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Hello, This is RFC v3 to allow AMD IBS to regular users on the default settings where kernel-level profiling is disabled (perf_event_paranoid=2). Currently AMD IBS doesn't allow any kind of exclusion in the event attribute. But users needs to set attr.exclude_kernel to open an event on such an environment. v3 changes) * fix build on s390 * add swfilt format for attr.config2 * count powerpc core-book3s dropped samples v2) https://lore.kernel.org/lkml/20240830232910.1839548-1-namhyung@kernel.org/ * add PERF_FORMAT_DROPPED * account dropped sw events and from BPF handler * use precise RIP from IBS record v1) https://lore.kernel.org/lkml/20240822230816.564262-1-namhyung@kernel.org/ While IBS doesn't support hardware level privilege filters, the kernel can allow the event and drop samples belongs to the kernel like in the software events. This is limited but it still contains precise samples which is important for various analysis like data type profiling. This version added format/swfilt file in sysfs to expose the software filtering by setting the attribute config2 value. I think it's easier to add a new config rather than adding a new PMU in order to handle event multiplexing across IBS PMU. Users can use the perf tool to enable this feature manually like below. Probably the perf tool can handle this automatically in the future. $ perf record -e ibs_op/swfilt=1/uh $PROG (Not sure if it's better to accept or ignore exclude_hv so that it can use ":u" modifier only.) In order to count those dropped samples correctly, I'd propose a new read format PERF_FORMAT_DROPPED same as we did for the lost samples. With this, it can count dropped samples in the software events and from the BPF overflow handler as well. Let me know what you think. Thanks, Namhyung Namhyung Kim (5): perf/core: Add PERF_FORMAT_DROPPED perf/core: Export perf_exclude_event() perf/core: Account dropped samples from BPF perf/powerpc: Count dropped samples in core-book3s PMU perf/x86: Relax privilege filter restriction on AMD IBS arch/powerpc/perf/core-book3s.c | 4 ++- arch/s390/kernel/perf_cpum_sf.c | 8 ++++-- arch/x86/events/amd/ibs.c | 50 ++++++++++++++++++++++++--------- include/linux/perf_event.h | 7 +++++ include/uapi/linux/perf_event.h | 5 +++- kernel/events/core.c | 27 ++++++++++++++---- 6 files changed, 77 insertions(+), 24 deletions(-) -- 2.46.0.469.g59c65b2a67-goog