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[23.128.96.18]) by mx.google.com with ESMTP id p14si20037494ils.62.2021.06.28.04.50.14; Mon, 28 Jun 2021 04:50:30 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=huawei.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232739AbhF1KwZ (ORCPT + 99 others); Mon, 28 Jun 2021 06:52:25 -0400 Received: from szxga02-in.huawei.com ([45.249.212.188]:5926 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232486AbhF1KwZ (ORCPT ); Mon, 28 Jun 2021 06:52:25 -0400 Received: from dggemv703-chm.china.huawei.com (unknown [172.30.72.54]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4GD46Q1nplz70yR; Mon, 28 Jun 2021 18:46:38 +0800 (CST) Received: from dggema757-chm.china.huawei.com (10.1.198.199) by dggemv703-chm.china.huawei.com (10.3.19.46) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2176.2; Mon, 28 Jun 2021 18:49:58 +0800 Received: from [127.0.0.1] (10.69.38.203) by dggema757-chm.china.huawei.com (10.1.198.199) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2; Mon, 28 Jun 2021 18:49:57 +0800 Subject: Re: [PATCH v7 2/2] drivers/perf: hisi: Add driver for HiSilicon PCIe PMU To: John Garry , Linuxarm , , , CC: , , , References: <1624532384-43002-1-git-send-email-liuqi115@huawei.com> <1624532384-43002-3-git-send-email-liuqi115@huawei.com> <485dcb90-01bc-766a-466a-f32563e2076f@huawei.com> <95de93f7-1618-5aa6-9a23-6445c5cb3515@huawei.com> <1b164e4b-b30b-f071-51fa-841cc76ec017@huawei.com> From: "liuqi (BA)" Message-ID: <403d09f8-6fe8-c04c-151b-40816c344b55@huawei.com> Date: Mon, 28 Jun 2021 18:49:57 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <1b164e4b-b30b-f071-51fa-841cc76ec017@huawei.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 8bit X-Originating-IP: [10.69.38.203] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To dggema757-chm.china.huawei.com (10.1.198.199) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/6/26 19:44, John Garry wrote: > On 26/06/2021 03:13, liuqi (BA) wrote: >> >> >> On 2021/6/25 23:53, John Garry wrote: >>> On 24/06/2021 11:59, Qi Liu wrote: >>>> + >>>> +/* >>>> + * Events with the "dl" suffix in their names count performance in >>>> DL layer, >>>> + * otherswise, events count performance in TL layer. >>>> + */ >>>> +static struct attribute *hisi_pcie_pmu_events_attr[] = { >>>> +    HISI_PCIE_PMU_EVENT_ATTR(bw_rx_mwr, 0x010004), >>>> +    HISI_PCIE_PMU_EVENT_ATTR(bw_rx_mrd, 0x100005), >>>> +    HISI_PCIE_PMU_EVENT_ATTR(bw_tx_mwr, 0x010005), >>>> +    HISI_PCIE_PMU_EVENT_ATTR(bw_tx_mrd, 0x200004), >>>> +    HISI_PCIE_PMU_EVENT_ATTR(lat_rx_mwr, 0x000010), >>>> +    HISI_PCIE_PMU_EVENT_ATTR(lat_rx_mrd, 0x020010), >>>> +    HISI_PCIE_PMU_EVENT_ATTR(lat_tx_mrd, 0x000011), >>>> +    HISI_PCIE_PMU_EVENT_ATTR(bw_rx_dl, 0x010084), >>>> +    HISI_PCIE_PMU_EVENT_ATTR(bw_tx_dl, 0x030084), >>>> +    NULL >>>> +}; >>>> + >>>> +static struct attribute_group hisi_pcie_pmu_events_group = { >>>> +    .name = "events", >>>> +    .attrs = hisi_pcie_pmu_events_attr, >>>> +}; >>>> + >>>> +static struct attribute *hisi_pcie_pmu_format_attr[] = { >>>> +    HISI_PCIE_PMU_FORMAT_ATTR(event, "config:0-15"), >>>> +    HISI_PCIE_PMU_FORMAT_ATTR(subevent, "config:16-23"), >>>> +    HISI_PCIE_PMU_FORMAT_ATTR(thr_len, "config1:0-3"), >>>> +    HISI_PCIE_PMU_FORMAT_ATTR(thr_mode, "config1:4"), >>>> +    HISI_PCIE_PMU_FORMAT_ATTR(trig_len, "config1:5-8"), >>>> +    HISI_PCIE_PMU_FORMAT_ATTR(trig_mode, "config1:9"), >>>> +    HISI_PCIE_PMU_FORMAT_ATTR(port, "config2:0-15"), >>>> +    HISI_PCIE_PMU_FORMAT_ATTR(bdf, "config2:16-31"), >>>> +    NULL >>>> +}; >>> >>> I am just wondering how this now works. >>> >>> So if the user programs the following: >>> ./perf stat -v -e hisi_pcieX/lat_rx_mrd/ >>> >>> Then the value (incremented) in HISI_PCIE_CNT (I think that's the >>> right one) is returned as the event count. But one would expect >>> bandwidth from that event, while we only return here the delay cycles >>> - how is the count in HISI_PCIE_CNT_EXT exposed, so userspace can do >>> the calc for bw? >>> >> > > Hi Qi, > >> >> Hardware counter and ext_counter work together for bandwidth, latency, >> bus utilization and buffer occupancy events. For example, for latency >> events(idx = 0x10), counter counts total delay cycles and ext_counter >> counts PCIe packets number. >> >> As we don't want PMU driver to process these two data, "delay cycles" >> can be treated as an event(id = 0x10), "packets number" as another event >> (id = 0x10 << 8), and driver could export these data separately. >> >> if the user want to calculate latency of rx memory read, they should: >> ./perf stat -v -e '{hisi_pcieX/event=0x10, >> subevent=0x01/,hisi_pcieX/event=0x0400, subevent=0x01/ >> >> and for bandwidth event: >> ./perf stat -v -e '{hisi_pcieX/event=0x4, >> subevent=0x02/,hisi_pcieX/event=0x1000, subevent=0x02/ > Hi John, > I would suggest supporting a perf metric for this then, which would be > like: > > { >    "BriefDescription": "Latency for inbound traffic...", >    "MetricName": "hisi_pcie_lat_rx_mrd", >    "MetricExpr": "hisi_pcieX@event\\=0x4@subevent\\=0x02 \ > hisi_pcieX@event\\=0x1000@subevent\\=0x02 \", >    "Unit": "hisi_pci", >    "Compat": "v1" > }, > > (syntax may be incorrect - illustration only) > yes, we could add these metrics in json file, thanks. >> >> Then the value in HISI_PCIE_CNT and HISI_PCIE_EXT_CNT returned >> separately, and userspace could do the calculation. > > But I am still curious about lat_rx_mrd and the other events which we > continue to advertise. They don't really provide latency or bandwidth on > their own, but only half the necessary data. So I doubt their purpose. > So how about changing the event name to show the real purpose of this event, like changing "bw_rx_mrd" to "flux_rx_mrd", and changing "lat_rx_mrd" to "delay_rx_mrd"? Thanks, Qi > Thanks, > John > > .