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[2620:137:e000::1:20]) by mx.google.com with ESMTP id sb9-20020a170906edc900b009937af8ac4asi4192223ejb.241.2023.08.01.05.51.06; Tue, 01 Aug 2023 05:51:30 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=huawei.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231506AbjHALqm (ORCPT + 99 others); Tue, 1 Aug 2023 07:46:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42104 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234464AbjHALqi (ORCPT ); Tue, 1 Aug 2023 07:46:38 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AEA921BE7; Tue, 1 Aug 2023 04:46:28 -0700 (PDT) Received: from canpemm500009.china.huawei.com (unknown [172.30.72.55]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4RFYBx13PTztRkB; Tue, 1 Aug 2023 19:43:05 +0800 (CST) Received: from [10.67.102.169] (10.67.102.169) by canpemm500009.china.huawei.com (7.192.105.203) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.27; Tue, 1 Aug 2023 19:46:25 +0800 CC: , , , , , , , , , , , , Subject: Re: [PATCH v6 3/4] drivers/perf: add DesignWare PCIe PMU driver To: Shuai Xue , Jonathan Cameron References: <20230606074938.97724-1-xueshuai@linux.alibaba.com> <20230606074938.97724-4-xueshuai@linux.alibaba.com> <31e2b012-3a29-d063-842d-e3f7736816e7@huawei.com> <20230727103929.00000544@Huawei.com> <12958abe-4bdb-8532-bf67-8e772ed2a9dd@linux.alibaba.com> From: Yicong Yang Message-ID: Date: Tue, 1 Aug 2023 19:46:25 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.5.1 MIME-Version: 1.0 In-Reply-To: <12958abe-4bdb-8532-bf67-8e772ed2a9dd@linux.alibaba.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.67.102.169] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To canpemm500009.china.huawei.com (7.192.105.203) X-CFilter-Loop: Reflected X-Spam-Status: No, score=-2.0 required=5.0 tests=BAYES_00,NICE_REPLY_A, RCVD_IN_DNSWL_BLOCKED,RCVD_IN_MSPIKE_H5,RCVD_IN_MSPIKE_WL, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023/7/28 20:41, Shuai Xue wrote: > > > On 2023/7/27 17:39, Jonathan Cameron wrote: >> On Tue, 6 Jun 2023 23:14:07 +0800 >> Yicong Yang wrote: >> >>> On 2023/6/6 15:49, Shuai Xue wrote: >>>> This commit adds the PCIe Performance Monitoring Unit (PMU) driver support >>>> for T-Head Yitian SoC chip. Yitian is based on the Synopsys PCI Express >>>> Core controller IP which provides statistics feature. The PMU is not a PCIe >>>> Root Complex integrated End Point(RCiEP) device but only register counters >>>> provided by each PCIe Root Port. >>>> >>>> To facilitate collection of statistics the controller provides the >>>> following two features for each Root Port: >>>> >>>> - Time Based Analysis (RX/TX data throughput and time spent in each >>>> low-power LTSSM state) >>>> - Event counters (Error and Non-Error for lanes) >>>> >>>> Note, only one counter for each type and does not overflow interrupt. >>>> >>>> This driver adds PMU devices for each PCIe Root Port. And the PMU device is >>>> named based the BDF of Root Port. For example, >>>> >>>> 30:03.0 PCI bridge: Device 1ded:8000 (rev 01) >>>> >>>> the PMU device name for this Root Port is dwc_rootport_3018. >>>> >>>> Example usage of counting PCIe RX TLP data payload (Units of 16 bytes):: >>>> >>>> $# perf stat -a -e dwc_rootport_3018/Rx_PCIe_TLP_Data_Payload/ >>>> >>>> average RX bandwidth can be calculated like this: >>>> >>>> PCIe TX Bandwidth = PCIE_TX_DATA * 16B / Measure_Time_Window >>>> >>>> Signed-off-by: Shuai Xue >>>> Reported-by: kernel test robot >>>> Link: https://lore.kernel.org/oe-kbuild-all/202305170639.XU3djFZX-lkp@intel.com/ >>>> Reviewed-by: Baolin Wang >> >> I'll review on top to avoid any duplication with Yicong. > > Thank you! It also served as a reminder that I missed Yicong's email. It appears > that Thunderbird mistakenly moved his email to the junk folder, resulting in me > overlooking it. > >> >> Note I've cropped the stuff neither of us commented on so it's >> easier to spot the feedback. > > Thank you for noting that. My feedback is replied inline. > >> >> Jonathan >> >>>> --- >>>> drivers/perf/Kconfig | 7 + >>>> drivers/perf/Makefile | 1 + >>>> drivers/perf/dwc_pcie_pmu.c | 706 ++++++++++++++++++++++++++++++++++++ >>>> 3 files changed, 714 insertions(+) >>>> create mode 100644 drivers/perf/dwc_pcie_pmu.c >>>> >>>> diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig >>>> index 711f82400086..6ff3921d7a62 100644 >>>> --- a/drivers/perf/Kconfig >>>> +++ b/drivers/perf/Kconfig >>>> @@ -209,6 +209,13 @@ config MARVELL_CN10K_DDR_PMU >>>> Enable perf support for Marvell DDR Performance monitoring >>>> event on CN10K platform. >>>> >>>> +config DWC_PCIE_PMU >>>> + tristate "Enable Synopsys DesignWare PCIe PMU Support" >>>> + depends on (ARM64 && PCI) >>>> + help >>>> + Enable perf support for Synopsys DesignWare PCIe PMU Performance >>>> + monitoring event on Yitian 710 platform. >> >> The documentation kind of implies this isn't platform specific. >> If some parts are (such as which events exist) then you may want to push >> that to userspace / perftool with appropriate matching against specific SoC. >> >> If it is generic, then change this text to "event on platform including the Yitian 710." > > It is generic without any platform specific, so I will change it as you expected. > >> >>>> + >>>> source "drivers/perf/arm_cspmu/Kconfig" >>>> >>>> source "drivers/perf/amlogic/Kconfig" >> >>>> new file mode 100644 >>>> index 000000000000..8bfcf6e0662d >>>> --- /dev/null >>>> +++ b/drivers/perf/dwc_pcie_pmu.c >>>> @@ -0,0 +1,706 @@ >> >> ... >> >>>> + >>>> +struct dwc_pcie_pmu { >>>> + struct pci_dev *pdev; /* Root Port device */ >>> >>> If the root port removed after the probe of this PCIe PMU driver, we'll access the NULL >>> pointer. I didn't see you hold the root port to avoid the removal. > > Do you mean that I should have a reference count of rootport by pci_dev_get() when allocating > pcie_pmu? > > pcie_pmu->pdev = pci_dev_get(); It could be one option, but will block the removal of device from userspace. Another option is to register a PCI bus notifier then on removal/added the driver can get notified and handle it, for example, remove the related PMU on the removal of the root ports.