From mboxrd@z Thu Jan 1 00:00:00 1970 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 5BF58C77B60 for ; Tue, 4 Apr 2023 16:56:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235528AbjDDQ4N (ORCPT ); Tue, 4 Apr 2023 12:56:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40920 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235629AbjDDQ4D (ORCPT ); Tue, 4 Apr 2023 12:56:03 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0FE8F4C20; Tue, 4 Apr 2023 09:55:43 -0700 (PDT) Received: from lhrpeml500005.china.huawei.com (unknown [172.18.147.226]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4PrYlc0FDZz67T1b; Wed, 5 Apr 2023 00:54:52 +0800 (CST) Received: from localhost (10.202.227.76) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.23; Tue, 4 Apr 2023 17:55:37 +0100 Date: Tue, 4 Apr 2023 17:55:37 +0100 From: Jonathan Cameron To: "Liang, Kan" CC: , , , , , , , , , , "Davidlohr Bueso" , Dave Jiang Subject: Re: [PATCH v4 5/5] docs: perf: Minimal introduction the the CXL PMU device and driver Message-ID: <20230404175537.00004782@Huawei.com> In-Reply-To: References: <20230330164556.31533-1-Jonathan.Cameron@huawei.com> <20230330164556.31533-6-Jonathan.Cameron@huawei.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.227.76] X-ClientProxiedBy: lhrpeml500004.china.huawei.com (7.191.163.9) To lhrpeml500005.china.huawei.com (7.191.163.240) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-perf-users@vger.kernel.org On Mon, 3 Apr 2023 13:45:52 -0400 "Liang, Kan" wrote: > On 2023-03-30 12:45 p.m., 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. > > > > Reviewed-by: Dave Jiang > > Signed-off-by: Jonathan Cameron > > > > -- > > v4: No change > > --- > > 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. > > The PMU only supports system-wide counting. That's the reason it doesn't > support per-task profiling. Not because of missing sampling. Ah. I've managed to fuse two different conditions. I'll break them apart for v5. Thanks, Jonathan > > Thanks, > Kan > > 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 >