From nobody Fri Oct 3 14:45:03 2025 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.14]) (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 3F26434AAFA for ; Fri, 29 Aug 2025 19:34:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.14 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756496056; cv=none; b=HBg6XfyxeVNXLYWPG38q64FiW3/76wHywqKoQBnNWbznifu07RzcIkuvUhPRDJAJYO/kiayRr2gMqBqtiOE+/IU0MslyOWbtml4D6xmJFG68TEN3dYj9w98AKqKd2eF3YNF6S7vd1nr1ADDr7te4GWz1Ws6opasOYx2DCl3PNok= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756496056; c=relaxed/simple; bh=zH8x13Si8Yt26D26LIpJslO/XLlS8cnq4VGztV5gLSc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=scGUbF3wEtYGPayKTe6y8Bq3jUcRmh4DI0WZa5BtEKEqsI+E+2PmcEn5+/MdlMIUoHW+PcbLn3Ze4FBl0mluRRA82g2eaKa0kY7bGixCmp8HTD7KwS92rRTrOwvN7ZZBrhrq7SILFd/ruWmDsrpUiI0547K3TsS9MdwXtrIJxHQ= 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=j0ujSXwl; arc=none smtp.client-ip=198.175.65.14 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="j0ujSXwl" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1756496054; x=1788032054; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=zH8x13Si8Yt26D26LIpJslO/XLlS8cnq4VGztV5gLSc=; b=j0ujSXwlLRlLDTwa6QByhh4ohD7kkTfPf+diQj3fTmJyYPv8zlb7+5sV lV11i5mWKUK50d/hQgpQnuSj3zyh3zZFqJ2PoTL/1hHTrzxjrH6xNd9qr qfo2emQSPId2w5iaOGcz/pN8vpm6oFEzKpCBbbXDCA56apZaEQAVcoJ6W DwVe/X6M6/FInGOHCfh+KkKzLGmGuqk8TmtG9LvYMgELR1gRlVuNcPhhd E5b97IVV2aMWgjhAPKjzW3M4x9RmWQWFyBnToP+48uGDtQLCLU/SKelYp Y+ZH9GJIz88Lmp7FZr0oEMXcHxLOkV0YbjJ47SNXH5qLXzLKlmobvibLC g==; X-CSE-ConnectionGUID: dKTMYly/Ts+NX1O6JswYtg== X-CSE-MsgGUID: afECRssMTCCeubOyaXCFmA== X-IronPort-AV: E=McAfee;i="6800,10657,11531"; a="62625385" X-IronPort-AV: E=Sophos;i="6.17,312,1747724400"; d="scan'208";a="62625385" Received: from fmviesa003.fm.intel.com ([10.60.135.143]) by orvoesa106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Aug 2025 12:33:57 -0700 X-CSE-ConnectionGUID: WmdEO+lgT4q+PvsXcrdEEg== X-CSE-MsgGUID: LIYzV1jVSam4d5NJlA7OZg== X-ExtLoop1: 1 Received: from ldmartin-desk2.corp.intel.com (HELO agluck-desk3.intel.com) ([10.124.220.202]) by fmviesa003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Aug 2025 12:33:57 -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 v9 31/31] x86,fs/resctrl: Update Documentation for package events Date: Fri, 29 Aug 2025 12:33:43 -0700 Message-ID: <20250829193346.31565-32-tony.luck@intel.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250829193346.31565-1-tony.luck@intel.com> References: <20250829193346.31565-1-tony.luck@intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Update resctrl filesystem documentation with the details about the resctrl files that support telemetry events. Signed-off-by: Tony Luck --- Documentation/filesystems/resctrl.rst | 99 +++++++++++++++++++++++---- 1 file changed, 86 insertions(+), 13 deletions(-) diff --git a/Documentation/filesystems/resctrl.rst b/Documentation/filesyst= ems/resctrl.rst index c7949dd44f2f..7ee2832a3aa6 100644 --- a/Documentation/filesystems/resctrl.rst +++ b/Documentation/filesystems/resctrl.rst @@ -167,13 +167,12 @@ with respect to allocation: bandwidth percentages are directly applied to the threads running on the core =20 -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: =20 "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. =20 "mon_features": Lists the monitoring events if @@ -261,6 +260,19 @@ with the following files: bytes) at which a previously used LLC_occupancy counter can be considered for re-use. =20 +If telemetry monitoring is available there will be an "PERF_PKG_MON" direc= tory +with the following files: + +"num_rmids": + The number of RMIDs supported by hardware for + telemetry monitoring events. + +"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 "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 @@ -366,15 +378,38 @@ When control is enabled all CTRL_MON groups will also= contain: When monitoring is enabled all MON groups will also contain: =20 "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 - MON groups. Please see example section for more details on usage. + This contains a set of directories, one for each instance + of an L3 cache, another for each processor package. The L3 cache + directories are named "mon_L3_00", "mon_L3_01" etc. The + package directories "mon_PERF_PKG_00", "mon_PERF_PKG_01" etc. + + Within each directory there is one file per event. For + example the L3 directories may contain "llc_occupancy", "mbm_total_bytes", + and "mbm_local_bytes". The PERF_PKG directories may contain "core_energy", + "activity", etc. + + "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 these two counters 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" @@ -1300,6 +1335,44 @@ Example with C:: resctrl_release_lock(fd); } =20 +Debugfs +=3D=3D=3D=3D=3D=3D=3D +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 will 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 when and how often the hardware has failed to +collect and accumulate data from the CPUs. 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 =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D Reading monitored data --=20 2.50.1