diff options
| author | Kan Liang <kan.liang@linux.intel.com> | 2023-01-31 10:37:38 +0300 |
|---|---|---|
| committer | Joerg Roedel <jroedel@suse.de> | 2023-02-03 13:06:08 +0300 |
| commit | 46284c6ceb5e4dfddcb00dafb7c2f3c1437fdca4 (patch) | |
| tree | 16a01376418a6683fc5e7f53813c52e77ab184aa /Documentation/ABI | |
| parent | 7232ab8b89e9ea32f07370643635a13641ce9c3c (diff) | |
| download | linux-46284c6ceb5e4dfddcb00dafb7c2f3c1437fdca4.tar.xz | |
iommu/vt-d: Support cpumask for IOMMU perfmon
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>
Diffstat (limited to 'Documentation/ABI')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-event_source-devices-iommu | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-event_source-devices-iommu b/Documentation/ABI/testing/sysfs-bus-event_source-devices-iommu index 988210a0e8ce..d7af4919302e 100644 --- a/Documentation/ABI/testing/sysfs-bus-event_source-devices-iommu +++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-iommu @@ -27,3 +27,11 @@ Description: Read-only. Attribute group to describe the magic bits filter_pasid = "config2:0-21" - PASID filter filter_ats = "config2:24-28" - Address Type filter filter_page_table = "config2:32-36" - Page Table Level filter + +What: /sys/bus/event_source/devices/dmar*/cpumask +Date: Jan 2023 +KernelVersion: 6.3 +Contact: Kan Liang <kan.liang@linux.intel.com> +Description: Read-only. This file always returns the CPU to which the + IOMMU pmu is bound for access to all IOMMU pmu performance + monitoring events. |