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 73327EB64DD for ; Fri, 4 Aug 2023 03:12:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232905AbjHDDMg (ORCPT ); Thu, 3 Aug 2023 23:12:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40094 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232583AbjHDDLd (ORCPT ); Thu, 3 Aug 2023 23:11:33 -0400 Received: from out30-133.freemail.mail.aliyun.com (out30-133.freemail.mail.aliyun.com [115.124.30.133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 030024EC9; Thu, 3 Aug 2023 20:09:23 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R501e4;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=15;SR=0;TI=SMTPD_---0Vp-n0Wm_1691118556; Received: from 30.240.114.112(mailfrom:xueshuai@linux.alibaba.com fp:SMTPD_---0Vp-n0Wm_1691118556) by smtp.aliyun-inc.com; Fri, 04 Aug 2023 11:09:20 +0800 Message-ID: <1ebf5862-441f-729a-32c1-8e59ac452168@linux.alibaba.com> Date: Fri, 4 Aug 2023 11:09:14 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.13.1 Subject: Re: [PATCH v6 3/4] drivers/perf: add DesignWare PCIe PMU driver Content-Language: en-US To: Yicong Yang , Jonathan Cameron Cc: yangyicong@hisilicon.com, chengyou@linux.alibaba.com, kaishen@linux.alibaba.com, helgaas@kernel.org, will@kernel.org, baolin.wang@linux.alibaba.com, robin.murphy@arm.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org, rdunlap@infradead.org, mark.rutland@arm.com, zhuo.song@linux.alibaba.com 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> <10176239-78c1-e276-e74f-a6e79b9c0751@linux.alibaba.com> From: Shuai Xue In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023/8/4 10:28, Yicong Yang wrote: > On 2023/8/4 9:39, Shuai Xue wrote: >> >> >> On 2023/8/1 19:46, Yicong Yang wrote: >>> 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. >> >> I see, but can root port be removed from userspace? I check the hotplug slot interface, no root >> port is available to power off. >> > > For hotplug maybe not, but user can remove certian device through sysfs: > > echo 1 > /sys/bus/pci/devices//remove > Thank you, I will add a notifier for removal/added action. Best Regards, Shuai