[PATCH V2 0/7] iommu/vt-d: Support performance monitoring for IOMMU
From: kan . liang
Date: Wed Jan 18 2023 - 15:50:38 EST
From: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
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 | 91 +-
drivers/iommu/intel/iommu.c | 3 +
drivers/iommu/intel/iommu.h | 101 ++-
drivers/iommu/intel/perfmon.c | 850 ++++++++++++++++++
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, 1151 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
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2.35.1