From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.9]) (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 8117130F523 for ; Mon, 13 Oct 2025 22:34:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.9 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760394863; cv=none; b=f4xSLkvBThbLCWVDwx4gxtM1LboauImjgAJdWWdcKXgYn+U7ILrzFe0b6jWXo1NMxCa+J9id3zsf7A431o3zTVSNoz2ZuoBwaxRaQerxigyUMFmsfXeyo6LpnFAx2mfSK35+wAEwWagrnNp4Tw4NDvV/+EcdFv/6CPMIwc2sE3k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760394863; c=relaxed/simple; bh=3RWvTnQSEkux+jTameRPS1qJv6hGBV+LzBX5eUtRyXE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PgwcKTp81trka8hidj6V42Ob7idS8p8QaDZkwFcTdjTHnpf9LTA7rGS58nl0xrpJqA/inE4+B9lIakxJBXwD0RtA9Ntqe+18RRsAuUknBds25IMOQLb6Lgx4Etef54Dyc5qC/6qQ3H7ixdhMSH67hp+ACnlgVBHfY2pZBwaXtnk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=CbZORJTl; arc=none smtp.client-ip=198.175.65.9 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="CbZORJTl" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1760394861; x=1791930861; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=3RWvTnQSEkux+jTameRPS1qJv6hGBV+LzBX5eUtRyXE=; b=CbZORJTlnc0ldfuQ1D6HZ3RgRZ44DHo2qWf6dJU0Y9sopEPaP43tIofa TGCifuTdsSHXhiruDr0PqavSNjZzS6WnEa0SxHJ2PB2XHxeO79Z73OzHq fO4gD0Vden7OMiJcP/JtHGriAK93Noph3xVwFh3eqpuwUxjiuRFtxULsU y0tRx25XiTNd6CAfbOtpAM7dBGnmPwkkPrKk5fhBo+YFX1xrL1VmfPeXg bVneuNNvm4dJGhd5nedliSJPATCJHCcBCFr/7WKCBq2UDame/veNjH9ee nA1v6e+kBHsaTWy/sA0HcYJdGJyDvLiLDyWoSvUJ+hIm20aH9I4aNbOLX w==; X-CSE-ConnectionGUID: W7UYyvs7TtGTDsC98KF+pg== X-CSE-MsgGUID: syqMxgd2QJmE7+WEp58GAg== X-IronPort-AV: E=McAfee;i="6800,10657,11581"; a="85168973" X-IronPort-AV: E=Sophos;i="6.19,226,1754982000"; d="scan'208";a="85168973" Received: from fmviesa008.fm.intel.com ([10.60.135.148]) by orvoesa101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Oct 2025 15:34:04 -0700 X-CSE-ConnectionGUID: anHY2+bURe6Xzfg7m7P5VQ== X-CSE-MsgGUID: 1G8zSumoR7qD3Y1SJvLmbw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.19,226,1754982000"; d="scan'208";a="182145348" Received: from sramkris-mobl1.amr.corp.intel.com (HELO agluck-desk3.intel.com) ([10.124.222.79]) by fmviesa008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Oct 2025 15:34:04 -0700 From: Tony Luck To: Fenghua Yu , Reinette Chatre , Maciej Wieczor-Retman , Peter Newman , James Morse , Babu Moger , Drew Fustini , Dave Martin , Chen Yu Cc: x86@kernel.org, linux-kernel@vger.kernel.org, patches@lists.linux.dev, Tony Luck Subject: [PATCH v12 31/31] x86,fs/resctrl: Update documentation for telemetry events Date: Mon, 13 Oct 2025 15:33:45 -0700 Message-ID: <20251013223348.103390-32-tony.luck@intel.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251013223348.103390-1-tony.luck@intel.com> References: <20251013223348.103390-1-tony.luck@intel.com> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Update resctrl filesystem documentation with the details about the resctrl files that support telemetry events. Signed-off-by: Tony Luck --- Documentation/filesystems/resctrl.rst | 102 +++++++++++++++++++++++--- 1 file changed, 90 insertions(+), 12 deletions(-) diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesystems/resctrl.rst index b7f35b07876a..5e4a5d4bbe9b 100644 --- a/Documentation/filesystems/resctrl.rst +++ b/Documentation/filesystems/resctrl.rst @@ -168,13 +168,12 @@ with respect to allocation: bandwidth percentages are directly applied to the threads running on the core -If RDT monitoring is available there will be an "L3_MON" directory +If L3 monitoring is available there will be an "L3_MON" directory with the following files: "num_rmids": - The number of RMIDs available. This is the - upper bound for how many "CTRL_MON" + "MON" - groups can be created. + The number of RMIDs supported by hardware for + L3 monitoring events. "mon_features": Lists the monitoring events if @@ -400,6 +399,24 @@ with the following files: bytes) at which a previously used LLC_occupancy counter can be considered for re-use. +If telemetry monitoring is available there will be an "PERF_PKG_MON" directory +with the following files: + +"num_rmids": + The number of RMIDs for telemetry monitoring events. By default, + resctrl will not enable telemetry events of a particular type + ("perf" or "energy") if the number of RMIDs supported is lower + than the number of RMIDs supported by the system. The user can + force-enable each type of telemetry events with the "rdt=" boot + command line option, but this will reduce the number of "MON" + groups that can be created. + +"mon_features": + Lists the telemetry monitoring events that are enabled on this system. + +The upper bound for how many "CTRL_MON" + "MON" can be created +is the smaller of the L3_MON and PERF_PKG_MON "num_rmids" values. + Finally, in the top level of the "info" directory there is a file named "last_cmd_status". This is reset with every "command" issued via the file system (making new directories or writing to any of the @@ -505,15 +522,40 @@ When control is enabled all CTRL_MON groups will also contain: When monitoring is enabled all MON groups will also contain: "mon_data": - This contains a set of files organized by L3 domain and by - RDT event. E.g. on a system with two L3 domains there will - be subdirectories "mon_L3_00" and "mon_L3_01". Each of these - directories have one file per event (e.g. "llc_occupancy", - "mbm_total_bytes", and "mbm_local_bytes"). In a MON group these - files provide a read out of the current value of the event for - all tasks in the group. In CTRL_MON groups these files provide - the sum for all tasks in the CTRL_MON group and all tasks in + This contains directories for each monitor domain. + + If L3 monitoring is enabled, there will be a "mon_L3_XX" directory for + each instance of an L3 cache. Each directory contains files for the enabled + L3 events (e.g. "llc_occupancy", "mbm_total_bytes", and "mbm_local_bytes"). + + If telemetry monitoring is enabled, there will be a "mon_PERF_PKG_YY" + directory for each physical processor package. Each directory contains + files for the enabled telemetry events (e.g. "core_energy". "activity", + "uops_retired", etc.) + + The info/`*`/mon_features files provide the full list of enabled + event/file names. + + "core energy" reports a floating point number for the energy (in Joules) + consumed by cores (registers, arithmetic units, TLB and L1/L2 caches) + during execution of instructions summed across all logical CPUs on a + package for the current RMID. + + "activity" also reports a floating point value (in Farads). This provides + an estimate of work done independent of the frequency that the CPUs used + for execution. + + Note that "core energy" and "activity" only measure energy/activity in the + "core" of the CPU (arithmetic units, TLB, L1 and L2 caches, etc.). They + do not include L3 cache, memory, I/O devices etc. + + All other events report decimal integer values. + + In a MON group these files provide a read out of the current value of + the event for all tasks in the group. In CTRL_MON groups these files + provide the sum for all tasks in the CTRL_MON group and all tasks in MON groups. Please see example section for more details on usage. + On systems with Sub-NUMA Cluster (SNC) enabled there are extra directories for each node (located within the "mon_L3_XX" directory for the L3 cache they occupy). These are named "mon_sub_L3_YY" @@ -1506,6 +1548,42 @@ Example with C:: resctrl_release_lock(fd); } +Debugfs +======= +In addition to the use of debugfs for tracing of pseudo-locking performance, +architecture code may create debugfs directories associated with monitoring +features for a specific resource. + +The full pathname for these is in the form: + + /sys/kernel/debug/resctrl/info/{resource_name}_MON/{arch}/ + +The presence, names, and format of these files may vary between architectures +even if the same resource is present. + +PERF_PKG_MON/x86_64 +------------------- +Three files are present per telemetry aggregator instance that show status. +The prefix of each file name describes the type ("energy" or "perf") which +processor package it belongs to, and the instance number of the aggregator. +For example: "energy_pkg1_agg2". + +The suffix describes which data is reported in the file and +is one of: + +data_loss_count: + This counts the number of times that this aggregator + failed to accumulate a counter value supplied by a CPU. + +data_loss_timestamp: + This is a "timestamp" from a free running 25MHz uncore + timer indicating when the most recent data loss occurred. + +last_update_timestamp: + Another 25MHz timestamp indicating when the + most recent counter update was successfully applied. + + Examples for RDT Monitoring along with allocation usage ======================================================= Reading monitored data -- 2.51.0