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The perf subsystem assumes that all counters are by default per-CPU. So the user space tool reads a counter from each CPU. However, the IOMMU counters are system-wide and can be read from any CPU. Here we use a CPU mask to restrict counting to one CPU to handle the issue. (with CPU hotplug notifier to choose a different CPU if the chosen one is taken off-line). The CPU is exposed to /sys/bus/event_source/devices/dmar*/cpumask for the user space perf tool. Signed-off-by: Kan Liang <kan.liang@linux.intel.com> Link: https://lore.kernel.org/r/20230128200428.1459118-6-kan.liang@linux.intel.com Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> Signed-off-by: Joerg Roedel <jroedel@suse.de>
38 lines
1.6 KiB
Plaintext
38 lines
1.6 KiB
Plaintext
What: /sys/bus/event_source/devices/dmar*/format
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Date: Jan 2023
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KernelVersion: 6.3
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Contact: Kan Liang <kan.liang@linux.intel.com>
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Description: Read-only. Attribute group to describe the magic bits
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that go into perf_event_attr.config,
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perf_event_attr.config1 or perf_event_attr.config2 for
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the IOMMU pmu. (See also
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ABI/testing/sysfs-bus-event_source-devices-format).
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Each attribute in this group defines a bit range in
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perf_event_attr.config, perf_event_attr.config1,
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or perf_event_attr.config2. All supported attributes
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are listed below (See the VT-d Spec 4.0 for possible
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attribute values)::
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event = "config:0-27" - event ID
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event_group = "config:28-31" - event group ID
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filter_requester_en = "config1:0" - Enable Requester ID filter
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filter_domain_en = "config1:1" - Enable Domain ID filter
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filter_pasid_en = "config1:2" - Enable PASID filter
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filter_ats_en = "config1:3" - Enable Address Type filter
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filter_page_table_en= "config1:4" - Enable Page Table Level filter
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filter_requester_id = "config1:16-31" - Requester ID filter
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filter_domain = "config1:32-47" - Domain ID filter
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filter_pasid = "config2:0-21" - PASID filter
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filter_ats = "config2:24-28" - Address Type filter
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filter_page_table = "config2:32-36" - Page Table Level filter
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What: /sys/bus/event_source/devices/dmar*/cpumask
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Date: Jan 2023
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KernelVersion: 6.3
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Contact: Kan Liang <kan.liang@linux.intel.com>
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Description: Read-only. This file always returns the CPU to which the
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IOMMU pmu is bound for access to all IOMMU pmu performance
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monitoring events.
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