Messages in this thread | | | From | kan.liang@linux ... | Subject | [PATCH V3 0/7] iommu/vt-d: Support performance monitoring for IOMMU | Date | Fri, 20 Jan 2023 08:54:01 -0800 |
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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
-- 2.35.1
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