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[v3,6/8] drivers/perf: hisi: Export associated CPUs of each PMU through sysfs

Message ID 20241026072424.29887-7-yangyicong@huawei.com (mailing list archive)
State New
Headers show
Series Refactor the common parts to the HiSilicon Uncore PMU core and cleanups | expand

Commit Message

Yicong Yang Oct. 26, 2024, 7:24 a.m. UTC 
From: Yicong Yang <yangyicong@hisilicon.com>

Although the event of the uncore PMU can only be opened on a single
CPU, some PMU does have the affinity on a range of CPUs. For example
the L3C PMU is associated to the CPUs sharing the L3T it monitors.
Users may infer this affinity by the PMU name which may have SCCL ID
and CCL ID encoded (for L3C etc), but it's not that straightforward.
So export this information by adding an "associated_cpus" sysfs
attribute then user can get this directly.

Reviewed-by: Jonathan Cameron <Joanthan.Cameron@huawei.com>
Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
---
 Documentation/admin-guide/perf/hisi-pmu.rst |  5 ++++-
 drivers/perf/hisilicon/hisi_uncore_pmu.c    | 10 ++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/Documentation/admin-guide/perf/hisi-pmu.rst b/Documentation/admin-guide/perf/hisi-pmu.rst
index 5cc248d18c63..2b3d5a90c34c 100644
--- a/Documentation/admin-guide/perf/hisi-pmu.rst
+++ b/Documentation/admin-guide/perf/hisi-pmu.rst
@@ -35,7 +35,10 @@  e.g. hisi_sccl1_hha0/rx_operations is RX_OPERATIONS event of HHA index #0 in
 SCCL ID #1.
 
 The driver also provides a "cpumask" sysfs attribute, which shows the CPU core
-ID used to count the uncore PMU event.
+ID used to count the uncore PMU event. An "associated_cpus" sysfs attribute is
+also provided to show the CPUs associated with this PMU. The "cpumask" indicates
+the CPUs to open the events, usually as a hit for userspaces tools like perf.
+It only contains one associated CPU from the "associated_cpus".
 
 Example usage of perf::
 
diff --git a/drivers/perf/hisilicon/hisi_uncore_pmu.c b/drivers/perf/hisilicon/hisi_uncore_pmu.c
index ac74d8312ee5..b27de6b3f9b4 100644
--- a/drivers/perf/hisilicon/hisi_uncore_pmu.c
+++ b/drivers/perf/hisilicon/hisi_uncore_pmu.c
@@ -51,8 +51,18 @@  EXPORT_SYMBOL_NS_GPL(hisi_cpumask_sysfs_show, HISI_PMU);
 
 static DEVICE_ATTR(cpumask, 0444, hisi_cpumask_sysfs_show, NULL);
 
+static ssize_t hisi_associated_cpus_sysfs_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct hisi_pmu *hisi_pmu = to_hisi_pmu(dev_get_drvdata(dev));
+
+	return cpumap_print_to_pagebuf(true, buf, &hisi_pmu->associated_cpus);
+}
+static DEVICE_ATTR(associated_cpus, 0444, hisi_associated_cpus_sysfs_show, NULL);
+
 static struct attribute *hisi_pmu_cpumask_attrs[] = {
 	&dev_attr_cpumask.attr,
+	&dev_attr_associated_cpus.attr,
 	NULL
 };