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SubjectRe: [PATCH V3 0/7] iommu/vt-d: Support performance monitoring for IOMMU
From
On 2023/1/21 0:54, kan.liang@linux.intel.com wrote:
> From: Kan Liang <kan.liang@linux.intel.com>
>
> Changes since V2:
> - Move ecmd_submit_sync() to iommu.c to avoid #ifdef CONFIG_INTEL_IOMMU
>
> Changes since V1:
> - The cap and ecap registers are always in the first page. It's not
> necessary to use the reg size in dmar_validate_one_drhd(). (Patch 1)
> - Move reg_size up and pair it with reg_base_addr in struct
> dmar_drhd_unit (Patch 1)
> - Update the year of Copyright (Patch 2)
> - Return 0 if PMS is not supported (Patch 2)
> - Refine the comments and add a pr_warn for per-counter capabilities
> check (Patch 2)
> - Remove unnecessary iommu_pmu->num_cntr = i (Patch 2)
> - Remove has_ob of ecmd_submit_sync() (Patch 3)
> - Remove the helpers from non-INTEL_IOMMU. (Patch 3)
> - Still keep #ifdef CONFIG_INTEL_IOMMU for ecmd_submit_sync() to
> avoid compile warning with non-INTEL_IOMMU config.
> - Use pr_warn_once() to replace WARN_ONCE() (Patch 4 & 6)
> - Free iommu PMU if it fails to be registered. (Patch 4)
> - Remove unnecessary 'handled' variable. (Patch 6)
>
> A performance monitoring infrastructure, perfmon, is introduced with
> the VT-d Spec 4.0. The purpose of perfmon is to support collection of
> information about key events occurring during operation of the remapping
> hardware, to aid performance tuning and debug. The patch series is to
> support the perfmon for IOMMU.
>
> To facilitate the perfmon support, the patch series also supports two
> new generic features of VT-d Spec 4.0.
> - Support the 'size' field to retrieve the accurate size of the register
> set for each dmar device from DRHD. (Patch 1)
> - Support the new Enhanced Command Interface. (Patch 3)
>
> With the patch series, users can collect the performance data of IOMMU
> via Linux perf tool. For example,
>
> $ perf stat -e dmar0/iommu_requests,filter_ats=0/ -a sleep 1
>
> Performance counter stats for 'system wide':
>
> 2135 dmar0/iommu_requests,filter_ats=0/
>
> 1.001087695 seconds time elapsed
>
> The IOMMU PMUs can be found under /sys/bus/event_source/devices/dmar*
>
> The available filters and event format can be found at the format folder
> $ ls /sys/bus/event_source/devices/dmar0/format/
> event event_group filter_ats filter_page_table
>
> The supported events can be found at the events folder
>
> $ ls /sys/bus/event_source/devices/dmar0/events/
> ats_blocked int_cache_hit_nonposted iommu_mrds
> pasid_cache_lookup
> ctxt_cache_hit int_cache_hit_posted iommu_requests
> pg_req_posted
> ctxt_cache_lookup int_cache_lookup iotlb_hit
> pw_occupancy
> fs_nonleaf_hit iommu_clocks iotlb_lookup
> ss_nonleaf_hit
> fs_nonleaf_lookup iommu_mem_blocked pasid_cache_hit
> ss_nonleaf_lookup
>
> Kan Liang (7):
> iommu/vt-d: Support size of the register set in DRHD
> iommu/vt-d: Retrieve IOMMU perfmon capability information
> iommu/vt-d: Support Enhanced Command Interface
> iommu/vt-d: Add IOMMU perfmon support
> iommu/vt-d: Support cpumask for IOMMU perfmon
> iommu/vt-d: Add IOMMU perfmon overflow handler support
> iommu/vt-d: Enable IOMMU perfmon support
>
> .../sysfs-bus-event_source-devices-iommu | 32 +
> drivers/iommu/intel/Kconfig | 9 +
> drivers/iommu/intel/Makefile | 1 +
> drivers/iommu/intel/dmar.c | 33 +-
> drivers/iommu/intel/iommu.c | 59 ++
> drivers/iommu/intel/iommu.h | 101 +-
> drivers/iommu/intel/perfmon.c | 860 ++++++++++++++++++
> drivers/iommu/intel/perfmon.h | 65 ++
> drivers/iommu/intel/svm.c | 2 +-
> include/acpi/actbl1.h | 2 +-
> include/linux/cpuhotplug.h | 1 +
> include/linux/dmar.h | 1 +
> 12 files changed, 1159 insertions(+), 7 deletions(-)
> create mode 100644 Documentation/ABI/testing/sysfs-bus-event_source-devices-iommu
> create mode 100644 drivers/iommu/intel/perfmon.c
> create mode 100644 drivers/iommu/intel/perfmon.h

Thanks for the work. The overall looks good to me now. But I am still
seeing some code style issues after running "./scripts/checkpatch.pl
--strict" scripts.

Can you please fix those issues and post a v4?

Best regards,
baolu

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