From: Yicong Yang <yangyicong@hisilicon.com> To: Suzuki K Poulose <suzuki.poulose@arm.com>, <linux-kernel@vger.kernel.org>, <linux-arm-kernel@lists.infradead.org>, <coresight@lists.linaro.org>, <linux-pci@vger.kernel.org> Cc: <alexander.shishkin@linux.intel.com>, <helgaas@kernel.org>, <gregkh@linuxfoundation.org>, <lorenzo.pieralisi@arm.com>, <will@kernel.org>, <mark.rutland@arm.com>, <mathieu.poirier@linaro.org>, <mike.leach@linaro.org>, <leo.yan@linaro.org>, <jonathan.cameron@huawei.com>, <song.bao.hua@hisilicon.com>, <john.garry@huawei.com>, <prime.zeng@huawei.com>, <liuqi115@huawei.com>, <zhangshaokun@hisilicon.com>, <linuxarm@huawei.com> Subject: Re: [PATCH RESEND 0/4] Add support for HiSilicon PCIe Tune and Trace device Date: Mon, 19 Apr 2021 21:21:38 +0800 [thread overview] Message-ID: <fb4e70d9-e5c8-1cbf-ca21-adb701089fe0@hisilicon.com> (raw) In-Reply-To: <529defac-cd67-3a7b-91d3-76eb0bb9dc6c@arm.com> On 2021/4/19 19:17, Suzuki K Poulose wrote: > On 17/04/2021 11:17, Yicong Yang wrote: >> [RESEND with perf and coresight folks Cc'ed] >> >> HiSilicon PCIe tune and trace device (PTT) is a PCIe Root Complex >> integrated Endpoint (RCiEP) device, providing the capability >> to dynamically monitor and tune the PCIe traffic (tune), >> and trace the TLP headers (trace). >> >> PTT tune is designed for monitoring and adjusting PCIe link parameters. >> We provide several parameters of the PCIe link. Through the driver, >> user can adjust the value of certain parameter to affect the PCIe link >> for the purpose of enhancing the performance in certian situation. > > ... > >> >> The reason for not using perf is because there is no current support >> for uncore tracing in the perf facilities. We have our own format >> of data and don't need perf doing the parsing. The setting through >> perf tools doesn't seem to be friendly as well. For example, >> we cannot count on perf to decode the usual format BDF number like >> <domain>:<bus>:<dev>.<fn>, which user can use to filter the TLP >> headers through the PTT device. >> >> A similar approach for implementing this function is ETM, which use >> sysfs for configuring and a character device for dumping data. >> >> Greg has some comments on our implementation and doesn't advocate >> to build driver on debugfs [1]. So I resend this series to >> collect more feedbacks on the implementation of this driver. >> >> Hi perf and ETM related experts, is it suggested to adapt this driver >> to perf? Or is the debugfs approach acceptable? Otherwise use >> sysfs + character device like ETM and use perf tools for decoding it? >> Any comments is welcomed. > > Please use perf. Debugfs / sysfs is not the right place for these things. > ok. > Also, please move your driver to drivers/perf/ > Does it make sense as it's a tuning and tracing device, and doesn't have counters nor do the sampling like usual PMU device under drivers/perf/. > As Alex mentioned, the ETM drivers were initially developed when the AUX > buffer was not available. The sysfs interface is there only for the backward compatibility and for bring up ( due to the nature of the > connections between the CoreSight components and sometimes the missing engineering spec). > got it. thanks for the explanation. Regards, Yicong > Suzuki > > .
WARNING: multiple messages have this Message-ID (diff)
From: Yicong Yang <yangyicong@hisilicon.com> To: Suzuki K Poulose <suzuki.poulose@arm.com>, <linux-kernel@vger.kernel.org>, <linux-arm-kernel@lists.infradead.org>, <coresight@lists.linaro.org>, <linux-pci@vger.kernel.org> Cc: <alexander.shishkin@linux.intel.com>, <helgaas@kernel.org>, <gregkh@linuxfoundation.org>, <lorenzo.pieralisi@arm.com>, <will@kernel.org>, <mark.rutland@arm.com>, <mathieu.poirier@linaro.org>, <mike.leach@linaro.org>, <leo.yan@linaro.org>, <jonathan.cameron@huawei.com>, <song.bao.hua@hisilicon.com>, <john.garry@huawei.com>, <prime.zeng@huawei.com>, <liuqi115@huawei.com>, <zhangshaokun@hisilicon.com>, <linuxarm@huawei.com> Subject: Re: [PATCH RESEND 0/4] Add support for HiSilicon PCIe Tune and Trace device Date: Mon, 19 Apr 2021 21:21:38 +0800 [thread overview] Message-ID: <fb4e70d9-e5c8-1cbf-ca21-adb701089fe0@hisilicon.com> (raw) In-Reply-To: <529defac-cd67-3a7b-91d3-76eb0bb9dc6c@arm.com> On 2021/4/19 19:17, Suzuki K Poulose wrote: > On 17/04/2021 11:17, Yicong Yang wrote: >> [RESEND with perf and coresight folks Cc'ed] >> >> HiSilicon PCIe tune and trace device (PTT) is a PCIe Root Complex >> integrated Endpoint (RCiEP) device, providing the capability >> to dynamically monitor and tune the PCIe traffic (tune), >> and trace the TLP headers (trace). >> >> PTT tune is designed for monitoring and adjusting PCIe link parameters. >> We provide several parameters of the PCIe link. Through the driver, >> user can adjust the value of certain parameter to affect the PCIe link >> for the purpose of enhancing the performance in certian situation. > > ... > >> >> The reason for not using perf is because there is no current support >> for uncore tracing in the perf facilities. We have our own format >> of data and don't need perf doing the parsing. The setting through >> perf tools doesn't seem to be friendly as well. For example, >> we cannot count on perf to decode the usual format BDF number like >> <domain>:<bus>:<dev>.<fn>, which user can use to filter the TLP >> headers through the PTT device. >> >> A similar approach for implementing this function is ETM, which use >> sysfs for configuring and a character device for dumping data. >> >> Greg has some comments on our implementation and doesn't advocate >> to build driver on debugfs [1]. So I resend this series to >> collect more feedbacks on the implementation of this driver. >> >> Hi perf and ETM related experts, is it suggested to adapt this driver >> to perf? Or is the debugfs approach acceptable? Otherwise use >> sysfs + character device like ETM and use perf tools for decoding it? >> Any comments is welcomed. > > Please use perf. Debugfs / sysfs is not the right place for these things. > ok. > Also, please move your driver to drivers/perf/ > Does it make sense as it's a tuning and tracing device, and doesn't have counters nor do the sampling like usual PMU device under drivers/perf/. > As Alex mentioned, the ETM drivers were initially developed when the AUX > buffer was not available. The sysfs interface is there only for the backward compatibility and for bring up ( due to the nature of the > connections between the CoreSight components and sometimes the missing engineering spec). > got it. thanks for the explanation. Regards, Yicong > Suzuki > > . _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-04-19 13:30 UTC|newest] Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-04-17 10:17 [PATCH RESEND 0/4] Add support for HiSilicon PCIe Tune and Trace device Yicong Yang 2021-04-17 10:17 ` Yicong Yang 2021-04-17 10:17 ` [PATCH RESEND 1/4] hwtracing: Add trace function " Yicong Yang 2021-04-17 10:17 ` Yicong Yang 2021-04-17 10:17 ` [PATCH RESEND 2/4] hwtracing: Add tune " Yicong Yang 2021-04-17 10:17 ` Yicong Yang 2021-04-17 10:17 ` [PATCH RESEND 3/4] docs: Add HiSilicon PTT device driver documentation Yicong Yang 2021-04-17 10:17 ` Yicong Yang 2021-04-19 9:07 ` Daniel Thompson 2021-04-19 9:07 ` Daniel Thompson 2021-04-19 13:12 ` Yicong Yang 2021-04-19 13:12 ` Yicong Yang 2021-04-17 10:17 ` [PATCH RESEND 4/4] MAINTAINERS: Add maintainer for HiSilicon PTT driver Yicong Yang 2021-04-17 10:17 ` Yicong Yang 2021-04-17 13:56 ` [PATCH RESEND 0/4] Add support for HiSilicon PCIe Tune and Trace device Alexander Shishkin 2021-04-17 13:56 ` Alexander Shishkin 2021-04-19 13:03 ` Yicong Yang 2021-04-19 13:03 ` Yicong Yang 2021-04-22 3:49 ` Leo Yan 2021-04-22 3:49 ` Leo Yan 2021-04-22 12:54 ` Yicong Yang 2021-04-22 12:54 ` Yicong Yang 2021-04-19 11:17 ` Suzuki K Poulose 2021-04-19 11:17 ` Suzuki K Poulose 2021-04-19 13:21 ` Yicong Yang [this message] 2021-04-19 13:21 ` Yicong Yang 2021-04-19 16:11 ` Suzuki K Poulose 2021-04-19 16:11 ` Suzuki K Poulose
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