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 11808C433EF for ; Thu, 23 Jun 2022 08:34:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230257AbiFWIev (ORCPT ); Thu, 23 Jun 2022 04:34:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46828 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229948AbiFWIes (ORCPT ); Thu, 23 Jun 2022 04:34:48 -0400 Received: from out199-1.us.a.mail.aliyun.com (out199-1.us.a.mail.aliyun.com [47.90.199.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4562243AD9 for ; Thu, 23 Jun 2022 01:34:47 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R111e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046050;MF=xueshuai@linux.alibaba.com;NM=1;PH=DS;RN=9;SR=0;TI=SMTPD_---0VHAqBee_1655973281; Received: from 30.240.120.144(mailfrom:xueshuai@linux.alibaba.com fp:SMTPD_---0VHAqBee_1655973281) by smtp.aliyun-inc.com; Thu, 23 Jun 2022 16:34:42 +0800 Message-ID: <4de128c7-4dec-6bb2-737e-656f5ab4ea8d@linux.alibaba.com> Date: Thu, 23 Jun 2022 16:34:40 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.10.0 From: Shuai Xue Subject: Re: [PATCH v1 1/3] docs: perf: Add description for Alibaba's T-Head PMU driver To: Jonathan Cameron Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, will@kernel.org, mark.rutland@arm.com, baolin.wang@linux.alibaba.com, yaohongbo@linux.alibaba.com, nengchen@linux.alibaba.com, zhuo.song@linux.alibaba.com References: <20220617111825.92911-1-xueshuai@linux.alibaba.com> <20220617111825.92911-2-xueshuai@linux.alibaba.com> <20220620124957.00006131@Huawei.com> Content-Language: en-US In-Reply-To: <20220620124957.00006131@Huawei.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2022/6/20 PM7:49, Jonathan Cameron 写道: > On Fri, 17 Jun 2022 19:18:23 +0800 > Shuai Xue wrote: > >> Alibaba's T-Head SoC implements uncore PMU for performance and functional >> debugging to facilitate system maintenance. Document it to provide guidance >> on how to use it. >> >> Signed-off-by: Shuai Xue > > Hi Shuia Xue, > > A few quick comments inline, > > Thanks, > > Jonathan Hi, Jonathan, Thank you very much for your quick comments. > >> --- >> .../admin-guide/perf/alibaba_pmu.rst | 94 +++++++++++++++++++ >> Documentation/admin-guide/perf/index.rst | 1 + >> 2 files changed, 95 insertions(+) >> create mode 100644 Documentation/admin-guide/perf/alibaba_pmu.rst >> >> diff --git a/Documentation/admin-guide/perf/alibaba_pmu.rst b/Documentation/admin-guide/perf/alibaba_pmu.rst >> new file mode 100644 >> index 000000000000..337f4f1d4c54 >> --- /dev/null >> +++ b/Documentation/admin-guide/perf/alibaba_pmu.rst >> @@ -0,0 +1,94 @@ >> +============================================================= >> +Alibaba's T-Head SoC Uncore Performance Monitoring Unit (PMU) >> +============================================================= >> + >> +The Yitian 710, custom-built by Alibaba Group's chip development business, >> +T-Head, implements uncore PMU for performance and functional debugging to >> +facilitate system maintenance. >> + >> +DDR Sub-System Driveway (DRW) PMU Driver >> +========================================= >> + >> +The Yitian 710 SoC supports the most advanced DDR5/4 DRAM to provide >> +tremendous memory bandwidth for cloud computing and HPC. The Driveway is a >> +module which is a bridge between a router of mesh network and memory >> +controller. It provides various functions like secure control, address map >> +and so on. > > I'd focus on the PMU aspect. No point in describing other features in this > document. Got it. I will delete this in next version. >> + >> +Yitian 710 employs eight DDR5/4 channels, four on each die. Each channel is >> +independent of others to service system memory requests. And one DDR5 > > Each DDR5 channel... Good catch, I will declare as DDR5 channel. > >> +channel is split into two independent sub-channels. The DDR Sub-System >> +Driveway implements separate PMUs for each sub-channel to monitor various >> +performance metrics. >> + >> +The Driveway PMU devices are named as ali_drw_ with perf. >> +For example, ali_drw_21000 and ali_drw_21080 are two PMU devices for two >> +sub-channels of the same channel in die 0. And the PMU device of die 1 is >> +prefixed with ali_drw_400XXXXX, e.g. ali_drw_40021000. >> + >> +Each sub-channel has 36 PMU counters in total, which is classified into >> +four groups: >> + >> +- Group 0: PMU Cycle Counter. This group has one pair of counters >> + pmu_cycle_cnt_low and pmu_cycle_cnt_high, that is used as the cycle count >> + based on DDRC core clock. >> + >> +- Group 1: PMU Bandwidth Counters. This group has 8 counters that are used >> + to count the total access number of either the eight bank groups in a >> + selected rank, or four ranks separately in the first 4 counters. The base >> + transfer unit is 64B. >> + >> +- Group 2: PMU Retry Counters. This group has 10 counters, that intend to >> + count the total retry number of each type of uncorrectable error. >> + >> +- Group 3: PMU Common Counters. This group has 16 counters, that are used >> + to count the common events. >> + >> +For now, the Driveway PMU driver only uses counters in group 0 and group 3. >> + >> +Example usage of counting memory data bandwidth:: >> + >> + perf stat \ >> + -e ali_drw_21000/perf_hif_wr/ \ > > What does hif stand for? Also, perf seems redundant for > a perf event. HIF stands for Host Interface which is a Synopsys’ custom-defined interface. On the host side, there is a choice of an AMBA 4 AXI interface or a custom Host Interface (HIF). The AMBA interface supports single or multi-port configurations, while the HIF supports a single port only. Read, write, and RMW requests as well as write data are received through the HIF. I will doc this in next version. The `perf` prefix means Performance Logging Signals in DDRC, I will remove it in next version. >> + -e ali_drw_21000/perf_hif_rd/ \ >> + -e ali_drw_21000/perf_hif_rmw/ \ >> + -e ali_drw_21000/perf_cycle/ \ >> + -e ali_drw_21080/perf_hif_wr/ \ >> + -e ali_drw_21080/perf_hif_rd/ \ >> + -e ali_drw_21080/perf_hif_rmw/ \ >> + -e ali_drw_21080/perf_cycle/ \ >> + -e ali_drw_23000/perf_hif_wr/ \ >> + -e ali_drw_23000/perf_hif_rd/ \ >> + -e ali_drw_23000/perf_hif_rmw/ \ >> + -e ali_drw_23000/perf_cycle/ \ >> + -e ali_drw_23080/perf_hif_wr/ \ >> + -e ali_drw_23080/perf_hif_rd/ \ >> + -e ali_drw_23080/perf_hif_rmw/ \ >> + -e ali_drw_23080/perf_cycle/ \ >> + -e ali_drw_25000/perf_hif_wr/ \ >> + -e ali_drw_25000/perf_hif_rd/ \ >> + -e ali_drw_25000/perf_hif_rmw/ \ >> + -e ali_drw_25000/perf_cycle/ \ >> + -e ali_drw_25080/perf_hif_wr/ \ >> + -e ali_drw_25080/perf_hif_rd/ \ >> + -e ali_drw_25080/perf_hif_rmw/ \ >> + -e ali_drw_25080/perf_cycle/ \ >> + -e ali_drw_27000/perf_hif_wr/ \ >> + -e ali_drw_27000/perf_hif_rd/ \ >> + -e ali_drw_27000/perf_hif_rmw/ \ >> + -e ali_drw_27000/perf_cycle/ \ >> + -e ali_drw_27080/perf_hif_wr/ \ >> + -e ali_drw_27080/perf_hif_rd/ \ >> + -e ali_drw_27080/perf_hif_rmw/ \ >> + -e ali_drw_27080/perf_cycle/ -- sleep 10 >> + >> +The average DRAM bandwidth can be calculated as follows: >> + >> +- Read Bandwidth = perf_hif_rd * DDRC_WIDTH * DDRC_Freq / DDRC_Cycle >> +- Write Bandwidth = (perf_hif_wr + perf_hif_rmw) * DDRC_WIDTH * DDRC_Freq / DDRC_Cycle >> + >> +Here, DDRC_WIDTH = 64 bytes. >> + >> +The current driver does not support sampling. So "perf record" is >> +unsupported. Also attach to a task is unsupported as the events are all >> +uncore. >> diff --git a/Documentation/admin-guide/perf/index.rst b/Documentation/admin-guide/perf/index.rst >> index 69b23f087c05..bf466ae91c6c 100644 >> --- a/Documentation/admin-guide/perf/index.rst >> +++ b/Documentation/admin-guide/perf/index.rst >> @@ -17,3 +17,4 @@ Performance monitor support >> xgene-pmu >> arm_dsu_pmu >> thunderx2-pmu >> + thead_pmu