Message-ID: <CANLsYkwqXQxBCYAHhd4Txv+AZVKgeX+C4kE0b1t3aytTthjNtQ@mail.gmail.com>
Date:   Thu, 1 Sep 2022 10:53:29 -0600
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     Yicong Yang <yangyicong@...wei.com>
Cc:     alexander.shishkin@...ux.intel.com, peterz@...radead.org,
        corbet@....net, gregkh@...uxfoundation.org,
        yangyicong@...ilicon.com, helgaas@...nel.org,
        lorenzo.pieralisi@....com, suzuki.poulose@....com, joro@...tes.org,
        shameerali.kolothum.thodi@...wei.com, mingo@...hat.com,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-pci@...r.kernel.org, linux-perf-users@...r.kernel.org,
        iommu@...ts.linux-foundation.org, iommu@...ts.linux.dev,
        linux-doc@...r.kernel.org, prime.zeng@...wei.com,
        liuqi115@...wei.com, zhangshaokun@...ilicon.com,
        linuxarm@...wei.com, bagasdotme@...il.com, john.garry@...wei.com,
        jonathan.cameron@...wei.com, leo.yan@...aro.org,
        james.clark@....com, robin.murphy@....com, will@...nel.org,
        acme@...nel.org, mark.rutland@....com
Subject: Re: [PATCH v12 0/5] Add driver support for HiSilicon PCIe Tune and
 Trace device

On Tue, 30 Aug 2022 at 04:59, Yicong Yang <yangyicong@...wei.com> wrote:
>
> A gentle ping for this...
>

I will look at this set next week.

> Thanks.
>
> On 2022/8/16 19:44, Yicong Yang wrote:
> > From: Yicong Yang <yangyicong@...ilicon.com>
> >
> > 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.
> >
> > PTT trace is designed for dumping the TLP headers to the memory, which can be
> > used to analyze the transactions and usage condition of the PCIe Link. Users
> > can choose filters to trace headers, by either requester ID, or those downstream
> > of a set of Root Ports on the same core of the PTT device. It's also supported
> > to trace the headers of certain type and of certain direction.
> >
> > The driver registers a PMU device for each PTT device. The trace can be used
> > through `perf record` and the traced headers can be decoded by `perf report`.
> > The tune can be used through the sysfs attributes of related PMU device. See
> > the documentation for the detailed usage.
> >
> > This patchset adds an initial driver support for the PTT device. The userspace
> > perf tool support will be sent in a separate patchset.
> >
> > Change since v11:
> > - Drop WARN_ON() for irq_set_affinity() failure per Greg
> > - Split out userspace perf support patches according to the comments
> > Link: https://lore.kernel.org/lkml/20220721130116.43366-1-yangyicong@huawei.com/
> >
> > Change since v10:
> > - Use title case in the documentation
> > - Add RB from Bagas, thanks.
> > Link: https://lore.kernel.org/lkml/20220714092710.53486-1-yangyicong@hisilicon.com/
> >
> > Change since v9:
> > - Add sysfs ABI description documentation
> > - Remove the controversial available_{root_port, requester}_filters sysfs file
> > - Shorten 2 tune sysfs attributes name and add some comments
> > - Move hisi_ptt_process_auxtrace_info() to Patch 6.
> > - Add RB from Leo and Ack-by from Mathieu, thanks!
> > Link: https://lore.kernel.org/lkml/20220606115555.41103-1-yangyicong@hisilicon.com/
> >
> > Change since v8:
> > - Cleanups and one minor fix from Jonathan and John, thanks
> > Link: https://lore.kernel.org/lkml/20220516125223.32012-1-yangyicong@hisilicon.com/
> >
> > Change since v7:
> > - Configure the DMA in probe rather than in runtime. Also use devres to manage
> >   PMU device as we have no order problem now
> > - Refactor the config validation function per John and Leo
> > - Use a spinlock hisi_ptt::pmu_lock instead of mutex to serialize the perf process
> >   in pmu::start as it's in atomic context
> > - Only commit the traced data when stop, per Leo and James
> > - Drop the filter dynamically updating patch from this series to simply the review
> >   of the driver. That patch will be send separately.
> > - add a cpumask sysfs attribute and handle the cpu hotplug events, follow the
> >   uncore PMU convention
> > - Other cleanups and fixes, both in driver and perf tool
> > Link: https://lore.kernel.org/lkml/20220407125841.3678-1-yangyicong@hisilicon.com/
> >
> > Change since v6:
> > - Fix W=1 errors reported by lkp test, thanks
> >
> > Change since v5:
> > - Squash the PMU patch into PATCH 2 suggested by John
> > - refine the commit message of PATCH 1 and some comments
> > Link: https://lore.kernel.org/lkml/20220308084930.5142-1-yangyicong@hisilicon.com/
> >
> > Change since v4:
> > Address the comments from Jonathan, John and Ma Ca, thanks.
> > - Use devm* also for allocating the DMA buffers
> > - Remove the IRQ handler stub in Patch 2
> > - Make functions waiting for hardware state return boolean
> > - Manual remove the PMU device as it should be removed first
> > - Modifier the orders in probe and removal to make them matched well
> > - Make available {directions,type,format} array const and non-global
> > - Using the right filter list in filters show and well protect the
> >   list with mutex
> > - Record the trace status with a boolean @started rather than enum
> > - Optimize the process of finding the PTT devices of the perf-tool
> > Link: https://lore.kernel.org/linux-pci/20220221084307.33712-1-yangyicong@hisilicon.com/
> >
> > Change since v3:
> > Address the comments from Jonathan and John, thanks.
> > - drop members in the common struct which can be get on the fly
> > - reduce buffer struct and organize the buffers with array instead of list
> > - reduce the DMA reset wait time to avoid long time busy loop
> > - split the available_filters sysfs attribute into two files, for root port
> >   and requester respectively. Update the documentation accordingly
> > - make IOMMU mapping check earlier in probe to avoid race condition. Also
> >   make IOMMU quirk patch prior to driver in the series
> > - Cleanups and typos fixes from John and Jonathan
> > Link: https://lore.kernel.org/linux-pci/20220124131118.17887-1-yangyicong@hisilicon.com/
> >
> > Change since v2:
> > - address the comments from Mathieu, thanks.
> >   - rename the directory to ptt to match the function of the device
> >   - spinoff the declarations to a separate header
> >   - split the trace function to several patches
> >   - some other comments.
> > - make default smmu domain type of PTT device to identity
> >   Drop the RMR as it's not recommended and use an iommu_def_domain_type
> >   quirk to passthrough the device DMA as suggested by Robin.
> > Link: https://lore.kernel.org/linux-pci/20211116090625.53702-1-yangyicong@hisilicon.com/
> >
> > Change since v1:
> > - switch the user interface of trace to perf from debugfs
> > - switch the user interface of tune to sysfs from debugfs
> > - add perf tool support to start trace and decode the trace data
> > - address the comments of documentation from Bjorn
> > - add RMR[1] support of the device as trace works in RMR mode or
> >   direct DMA mode. RMR support is achieved by common APIs rather
> >   than the APIs implemented in [1].
> > Link: https://lore.kernel.org/lkml/1618654631-42454-1-git-send-email-yangyicong@hisilicon.com/
> > [1] https://lore.kernel.org/linux-acpi/20210805080724.480-1-shameerali.kolothum.thodi@huawei.com/
> >
> > Yicong Yang (5):
> >   iommu/arm-smmu-v3: Make default domain type of HiSilicon PTT device to
> >     identity
> >   hwtracing: hisi_ptt: Add trace function support for HiSilicon PCIe
> >     Tune and Trace device
> >   hwtracing: hisi_ptt: Add tune function support for HiSilicon PCIe Tune
> >     and Trace device
> >   docs: trace: Add HiSilicon PTT device driver documentation
> >   MAINTAINERS: Add maintainer for HiSilicon PTT driver
> >
> >  .../ABI/testing/sysfs-devices-hisi_ptt        |   61 +
> >  Documentation/trace/hisi-ptt.rst              |  298 +++++
> >  Documentation/trace/index.rst                 |    1 +
> >  MAINTAINERS                                   |    8 +
> >  drivers/Makefile                              |    1 +
> >  drivers/hwtracing/Kconfig                     |    2 +
> >  drivers/hwtracing/ptt/Kconfig                 |   12 +
> >  drivers/hwtracing/ptt/Makefile                |    2 +
> >  drivers/hwtracing/ptt/hisi_ptt.c              | 1047 +++++++++++++++++
> >  drivers/hwtracing/ptt/hisi_ptt.h              |  200 ++++
> >  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   |   21 +
> >  11 files changed, 1653 insertions(+)
> >  create mode 100644 Documentation/ABI/testing/sysfs-devices-hisi_ptt
> >  create mode 100644 Documentation/trace/hisi-ptt.rst
> >  create mode 100644 drivers/hwtracing/ptt/Kconfig
> >  create mode 100644 drivers/hwtracing/ptt/Makefile
> >  create mode 100644 drivers/hwtracing/ptt/hisi_ptt.c
> >  create mode 100644 drivers/hwtracing/ptt/hisi_ptt.h
> >

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