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 31B20380 for ; Wed, 23 Oct 2024 00:09:29 +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=1729642170; cv=none; b=DFMgmjc6l8fMhTqOifmVPQSdQOcP6bd897lw0K/be8h/dUr92gq6falR+HbS5fn/YkQBexljXU2R5RIo/RY/LzLrVFEZVtycy67iUTJ4JrKg9b4nGnd4++MsZ2Nxg6Xm5zGo2fiQ/6epTF5JPjkYZmroreN2pCcl0vpNQ0BOzSs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729642170; c=relaxed/simple; bh=7rlz7NmdWwCUF+DnjzaiHZPWW98Cm9/UVt7DJkGgtes=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=r/4dq/y7YVaGg0kkzrIwvntOIeMjR79SsYRMzCngHxza3xP2B6sA6CGl0hJZIYbazxt4yK0fZNjMhGlRlKhdOui91XJlqrx3w4UFQDljFWhF4mKJmLVWykZTeEcGuGsz2LwMpMHNmkK2Zqric7dq9HwZcDxBITMPaVIo1CNUb34= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=q38IhB88; 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="q38IhB88" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 65871C4CEC3; Wed, 23 Oct 2024 00:09:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1729642169; bh=7rlz7NmdWwCUF+DnjzaiHZPWW98Cm9/UVt7DJkGgtes=; h=From:To:Cc:Subject:Date:From; b=q38IhB88hYg9FwlfkkHwpaCmwsrxDNPLtomPFOsEFmZS2sK8lZMF50GdyCbb2upMI TWyYa2YY6GKcRM7zDF3Ewqw1cYgf8ie/Ias4frXNK7TLG2809UDq9PPEfInU8fLOCM 9fwWJN5y8HhmeywerBXX685ppmMoMCOJACuT4s8S5LUjf69TfOVF0b0FsxMXmW8sU0 DevFBMGjWu1CT2OIdqCyYMzMHYikZjZ7m+Ap/PQ2TAmEmdbjsNQ31VCVDo/kwa7k89 pukRoW63u8D2N2GPjd3Vtxjck2ozFbsnU6cMp7FiarYSJAXPHg/yEIXjhzT0qJ3fsH MsZE/5nCgNLnA== From: Namhyung Kim To: Peter Zijlstra , Ingo Molnar Cc: Kan Liang , Mark Rutland , Alexander Shishkin , Arnaldo Carvalho de Melo , LKML , Stephane Eranian , Ravi Bangoria , Sandipan Das Subject: [PATCH v4 0/5] perf: Relax privilege restriction on AMD IBS Date: Tue, 22 Oct 2024 17:09:23 -0700 Message-ID: <20241023000928.957077-1-namhyung@kernel.org> X-Mailer: git-send-email 2.47.0.105.g07ac214952-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. v4 changes) * remove RFC tag * fix sysfs attribute for ibs_fetch/format (Ravi) * handle exclude_hv as well, so ":u" modifier would work for IBS * add Acked and Reviewed-by from Kyle and Madhavan v3 https://lore.kernel.org/lkml/20240905031027.2567913-1-namhyung@kernel.org * 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/u $PROG 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 | 59 +++++++++++++++++++++++---------- include/linux/perf_event.h | 7 ++++ include/uapi/linux/perf_event.h | 5 ++- kernel/events/core.c | 27 ++++++++++++--- 6 files changed, 82 insertions(+), 28 deletions(-) base-commit: de20037e1b3c2f2ca97b8c12b8c7bca8abd509a7 -- 2.47.0.105.g07ac214952-goog