Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 31E24C7EE2F for ; Fri, 3 Mar 2023 18:35:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231804AbjCCSfK (ORCPT ); Fri, 3 Mar 2023 13:35:10 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33634 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231696AbjCCSfE (ORCPT ); Fri, 3 Mar 2023 13:35:04 -0500 Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9CFA1C14E; Fri, 3 Mar 2023 10:34:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1677868498; x=1709404498; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=YavG9SzN7R2V9f06OiIdyohGAgtDlBxsdq17qor+UyE=; b=joVYnowMZa4NdX4IUnLgCqm77L1bPaNazN4DZw2Q9UkbFS2M3XuZoyBX q9Gv66HA/9d3kY/EgH0XZpEGjlx4lsRYigZNNUFEQkyIWU1JZHK7dyNs9 Bm1MI/Q0t17dDmxwoGZahFonoI7O02BAnsmGlR+qx43OViITauVSeudFQ 5cuoGOsHXGkBii5RRewA9jCzqWERezNNEIseBk1HZmh6Dwi1lzFaiDUot pizgmdXm+PvRVKYuOwOa8eLTrio5HDedmM/T+mNfGGyqiXDZ2Ji89onzW lYKnuifsPXuwL5NCF0KSlUWpYf9piEqAuHnGtcSorE+rf3zHDhNi+NlTV A==; X-IronPort-AV: E=McAfee;i="6500,9779,10638"; a="399931576" X-IronPort-AV: E=Sophos;i="5.98,231,1673942400"; d="scan'208";a="399931576" Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Mar 2023 10:34:42 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10638"; a="675456279" X-IronPort-AV: E=Sophos;i="5.98,231,1673942400"; d="scan'208";a="675456279" Received: from djiang5-mobl3.amr.corp.intel.com (HELO [10.209.141.249]) ([10.209.141.249]) by orsmga002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Mar 2023 10:34:41 -0800 Message-ID: <4dabd301-32d7-968e-e048-8135b072a7b5@intel.com> Date: Fri, 3 Mar 2023 11:34:37 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Firefox/102.0 Thunderbird/102.6.0 Subject: Re: [PATCH 4/4] docs: perf: Minimal introduction the the CXL PMU device and driver. Content-Language: en-US To: Jonathan Cameron , linux-cxl@vger.kernel.org Cc: peterz@infradead.org, mingo@redhat.com, acme@kernel.org, mark.rutland@arm.com, will@kernel.org, dan.j.williams@intel.com, bwidawsk@kernel.org, ira.weiny@intel.com, vishal.l.verma@intel.com, alison.schofield@intel.com, linuxarm@huawei.com, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org References: <20230303175022.10806-1-Jonathan.Cameron@huawei.com> <20230303175022.10806-5-Jonathan.Cameron@huawei.com> From: Dave Jiang In-Reply-To: <20230303175022.10806-5-Jonathan.Cameron@huawei.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/3/23 10:50 AM, Jonathan Cameron wrote: > Very basic introduction to the device and the current driver support > provided. I expect to expand on this in future versions of this patch > set. > > Signed-off-by: Jonathan Cameron Reviewed-by: Dave Jiang > > -- > v1: > - Add docs for how to use a Vendor Defined Counter. > RFC: > - I'll post separately about this shortly, but it seems very odd > to me that there is no way to assign a parent to an event_sources > device. As a result we get the messy approach of playing match > the name to figure out what the CPMU instance is connected to. Would it be too awkward to encode the parent name into the cpmu name? > --- > Documentation/admin-guide/perf/cxl.rst | 65 ++++++++++++++++++++++++ > Documentation/admin-guide/perf/index.rst | 1 + > 2 files changed, 66 insertions(+) > > diff --git a/Documentation/admin-guide/perf/cxl.rst b/Documentation/admin-guide/perf/cxl.rst > new file mode 100644 > index 000000000000..46235dff4b21 > --- /dev/null > +++ b/Documentation/admin-guide/perf/cxl.rst > @@ -0,0 +1,65 @@ > +.. SPDX-License-Identifier: GPL-2.0 > + > +====================================== > +CXL Performance Monitoring Unit (CPMU) > +====================================== > + > +The CXL rev 3.0 specification provides a definition of CXL Performance > +Monitoring Unit in section 13.2: Performance Monitoring. > + > +CXL components (e.g. Root Port, Switch Upstream Port, End Point) may have > +any number of CPMU instances. CPMU capabilities are fully discoverable from > +the devices. The specification provides event definitions for all CXL protocol > +message types and a set of additional events for things commonly counted on > +CXL devices (e.g. DRAM events). > + > +CPMU driver > +=========== > + > +The CPMU driver register a perf PMU with the name cpmu on the CXL bus. > + > + /sys/bus/cxl/device/cpmu > + > +The associated PMU is registered as > + > + /sys/bus/event_sources/devices/cpmu > + > +In common with other CXL bus devices, the id has no specific meaning and the > +relationship to specific CXL device should be established via the device parent > +of the device on the CXL bus. > + > +PMU driver provides description of available events and filter options in sysfs. > + > +The "format" directory describes all formats of the config (event vendor id, > +group id and mask) config1 (threshold, filter enables) and config2 (filter > +parameters) fields of the perf_event_attr structure. The "events" directory > +describes all documented events show in perf list. > + > +The events shown in perf list are the most fine grained events with a single > +bit of the event mask set. More general events may be enable by setting > +multiple mask bits in config. For example, all Device to Host Read Requests > +may be captured on a single counter by setting the bits for all of > + > +* d2h_req_rdcurr > +* d2h_req_rdown > +* d2h_req_rdshared > +* d2h_req_rdany > +* d2h_req_rdownnodata > + > +Example of usage:: > + > + $#perf list > + cpmu0/clock_ticks/ [Kernel PMU event] > + cpmu0/d2h_req_itomwr/ [Kernel PMU event] > + cpmu0/d2h_req_rdany/ [Kernel PMU event] > + cpmu0/d2h_req_rdcurr/ [Kernel PMU event] > + ----------------------------------------------------------- > + > + $# perf stat -e cpmu0/clock_ticks/ -e cpmu0/d2h_req_itowrm/ > + > +Vendor specific events may also be available and if so can be used via > + > + $# perf stat -e cpmu0/vid=VID,gid=GID,mask=MASK/ > + > +The driver does not support sampling. So "perf record" and attaching to > +a task are unsupported. > diff --git a/Documentation/admin-guide/perf/index.rst b/Documentation/admin-guide/perf/index.rst > index 9de64a40adab..f60be04e4e33 100644 > --- a/Documentation/admin-guide/perf/index.rst > +++ b/Documentation/admin-guide/perf/index.rst > @@ -21,3 +21,4 @@ Performance monitor support > alibaba_pmu > nvidia-pmu > meson-ddr-pmu > + cxl