perf/rapl: fix sysfs_show() initialization for RAPL PMU

PATCH New Stephane Eranian 2 participants 2 messages Jan 13, 2015 – Jan 16, 2015

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x86 perf events

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Stephane Eranian

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2015-01-13 22:59 UTC #0 lore raw

PATCH 1/1 perf/rapl: fix sysfs_show() initialization for RAPL PMU

This patch fixes a problem with the initialization of the sysfs_show() routine for the RAPL PMU.

The current code was wrongly relying on the EVENT_ATTR_STR() macro which uses the events_sysfs_show() function in the x86 PMU code. That function itself was relying on the x86_pmu data structure. Yet RAPL and the core PMU (x86_pmu) have nothing to do with each other. They should therefore not interact with each other.

The x86_pmu structure is initialized at boot time based on the host CPU model. When the host CPU is not supported, the x86_pmu remains uninitialized and some of the callbacks it contains are NULL.

The false dependency with x86_pmu could potentially cause crashes in case the x86_pmu is not initialized while the RAPL PMU is. This may, for instance, be the case in virtualized environments.

This patch fixes the problem by using a private sysfs_show() routine for exporting the RAPL PMU events.

Signed-off-by Stephane Eranian <[email protected]>

---
 arch/x86/kernel/cpu/perf_event_intel_rapl.c | 44 +++++++++++++++++++++--------
 1 file changed, 32 insertions(+), 12 deletions(-)

arch/x86/kernel/cpu/perf_event_intel_rapl.c +32 ~~-12~~

index 673f930..6e434f8 100644
@@ -103,6 +103,13 @@ static struct kobj_attribute format_attr_##_var =		\
 
 #define RAPL_CNTR_WIDTH 32 /* 32-bit rapl counters */
 
+#define RAPL_EVENT_ATTR_STR(_name, v, str)				\
+static struct perf_pmu_events_attr event_attr_##v = {			\
+	.attr		= __ATTR(_name, 0444, rapl_sysfs_show, NULL),	\
+	.id		= 0,						\
+	.event_str	= str,						\
+};
+
 struct rapl_pmu {
 	spinlock_t	 lock;
 	int		 hw_unit;  /* 1/2^hw_unit Joule */

@@ -379,23 +386,36 @@ static struct attribute_group rapl_pmu_attr_group = {
 	.attrs = rapl_pmu_attrs,
 };
 
-EVENT_ATTR_STR(energy-cores, rapl_cores, "event=0x01");
-EVENT_ATTR_STR(energy-pkg  ,   rapl_pkg, "event=0x02");
-EVENT_ATTR_STR(energy-ram  ,   rapl_ram, "event=0x03");
-EVENT_ATTR_STR(energy-gpu  ,   rapl_gpu, "event=0x04");
+static ssize_t rapl_sysfs_show(struct device *dev,
+			       struct device_attribute *attr,
+			       char *page)
+{
+	struct perf_pmu_events_attr *pmu_attr = \
+		container_of(attr, struct perf_pmu_events_attr, attr);
+
+	if (pmu_attr->event_str)
+		return sprintf(page, "%s", pmu_attr->event_str);
+
+	return 0;
+}
+
+RAPL_EVENT_ATTR_STR(energy-cores, rapl_cores, "event=0x01");
+RAPL_EVENT_ATTR_STR(energy-pkg  ,   rapl_pkg, "event=0x02");
+RAPL_EVENT_ATTR_STR(energy-ram  ,   rapl_ram, "event=0x03");
+RAPL_EVENT_ATTR_STR(energy-gpu  ,   rapl_gpu, "event=0x04");
 
-EVENT_ATTR_STR(energy-cores.unit, rapl_cores_unit, "Joules");
-EVENT_ATTR_STR(energy-pkg.unit  ,   rapl_pkg_unit, "Joules");
-EVENT_ATTR_STR(energy-ram.unit  ,   rapl_ram_unit, "Joules");
-EVENT_ATTR_STR(energy-gpu.unit  ,   rapl_gpu_unit, "Joules");
+RAPL_EVENT_ATTR_STR(energy-cores.unit, rapl_cores_unit, "Joules");
+RAPL_EVENT_ATTR_STR(energy-pkg.unit  ,   rapl_pkg_unit, "Joules");
+RAPL_EVENT_ATTR_STR(energy-ram.unit  ,   rapl_ram_unit, "Joules");
+RAPL_EVENT_ATTR_STR(energy-gpu.unit  ,   rapl_gpu_unit, "Joules");
 
 /*
  * we compute in 0.23 nJ increments regardless of MSR
  */
-EVENT_ATTR_STR(energy-cores.scale, rapl_cores_scale, "2.3283064365386962890625e-10");
-EVENT_ATTR_STR(energy-pkg.scale,     rapl_pkg_scale, "2.3283064365386962890625e-10");
-EVENT_ATTR_STR(energy-ram.scale,     rapl_ram_scale, "2.3283064365386962890625e-10");
-EVENT_ATTR_STR(energy-gpu.scale,     rapl_gpu_scale, "2.3283064365386962890625e-10");
+RAPL_EVENT_ATTR_STR(energy-cores.scale, rapl_cores_scale, "2.3283064365386962890625e-10");
+RAPL_EVENT_ATTR_STR(energy-pkg.scale,     rapl_pkg_scale, "2.3283064365386962890625e-10");
+RAPL_EVENT_ATTR_STR(energy-ram.scale,     rapl_ram_scale, "2.3283064365386962890625e-10");
+RAPL_EVENT_ATTR_STR(energy-gpu.scale,     rapl_gpu_scale, "2.3283064365386962890625e-10");
 
 static struct attribute *rapl_events_srv_attr[] = {
 	EVENT_PTR(rapl_cores),

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1.9.1

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2015-01-16 08:43 UTC #1 lore raw

[tip:perf/urgent] perf/rapl: Fix sysfs_show() initialization for RAPL PMU

perf/rapl: Fix sysfs_show() initialization for RAPL PMU

Commit-ID:  433678bdc6ed39f053c55da96b51de5bf0aeebb1
Gitweb:     http://git.kernel.org/tip/433678bdc6ed39f053c55da96b51de5bf0aeebb1
Author:     Stephane Eranian <[email protected]>
AuthorDate: Tue, 13 Jan 2015 23:59:53 +0100
Committer:  Ingo Molnar <[email protected]>
CommitDate: Fri, 16 Jan 2015 09:06:58 +0100

perf/rapl: Fix sysfs_show() initialization for RAPL PMU

This patch fixes a problem with the initialization of the sysfs_show() routine for the RAPL PMU.

The false dependency with x86_pmu could potentially cause crashes in case the x86_pmu is not initialized while the RAPL PMU is. This may, for instance, be the case in virtualized environments.

This patch fixes the problem by using a private sysfs_show() routine for exporting the RAPL PMU events.

Signed-off-by Stephane Eranian <[email protected]>

Signed-off-by Peter Zijlstra (Intel) <[email protected]>

Link http://lkml.kernel.org/r/20150113225953.GA21525@thinkpad open here

Cc [email protected]

Cc Arnaldo Carvalho de Melo <[email protected]>

Cc Linus Torvalds <[email protected]>

Signed-off-by Ingo Molnar <[email protected]>

---
 arch/x86/kernel/cpu/perf_event_intel_rapl.c | 44 +++++++++++++++++++++--------
 1 file changed, 32 insertions(+), 12 deletions(-)

arch/x86/kernel/cpu/perf_event_intel_rapl.c +32 ~~-12~~

index 673f930..6e434f8 100644
@@ -103,6 +103,13 @@ static struct kobj_attribute format_attr_##_var =		\
 
 #define RAPL_CNTR_WIDTH 32 /* 32-bit rapl counters */
 
+#define RAPL_EVENT_ATTR_STR(_name, v, str)				\
+static struct perf_pmu_events_attr event_attr_##v = {			\
+	.attr		= __ATTR(_name, 0444, rapl_sysfs_show, NULL),	\
+	.id		= 0,						\
+	.event_str	= str,						\
+};
+
 struct rapl_pmu {
 	spinlock_t	 lock;
 	int		 hw_unit;  /* 1/2^hw_unit Joule */

@@ -379,23 +386,36 @@ static struct attribute_group rapl_pmu_attr_group = {
 	.attrs = rapl_pmu_attrs,
 };
 
-EVENT_ATTR_STR(energy-cores, rapl_cores, "event=0x01");
-EVENT_ATTR_STR(energy-pkg  ,   rapl_pkg, "event=0x02");
-EVENT_ATTR_STR(energy-ram  ,   rapl_ram, "event=0x03");
-EVENT_ATTR_STR(energy-gpu  ,   rapl_gpu, "event=0x04");
+static ssize_t rapl_sysfs_show(struct device *dev,
+			       struct device_attribute *attr,
+			       char *page)
+{
+	struct perf_pmu_events_attr *pmu_attr = \
+		container_of(attr, struct perf_pmu_events_attr, attr);
+
+	if (pmu_attr->event_str)
+		return sprintf(page, "%s", pmu_attr->event_str);
+
+	return 0;
+}
+
+RAPL_EVENT_ATTR_STR(energy-cores, rapl_cores, "event=0x01");
+RAPL_EVENT_ATTR_STR(energy-pkg  ,   rapl_pkg, "event=0x02");
+RAPL_EVENT_ATTR_STR(energy-ram  ,   rapl_ram, "event=0x03");
+RAPL_EVENT_ATTR_STR(energy-gpu  ,   rapl_gpu, "event=0x04");
 
-EVENT_ATTR_STR(energy-cores.unit, rapl_cores_unit, "Joules");
-EVENT_ATTR_STR(energy-pkg.unit  ,   rapl_pkg_unit, "Joules");
-EVENT_ATTR_STR(energy-ram.unit  ,   rapl_ram_unit, "Joules");
-EVENT_ATTR_STR(energy-gpu.unit  ,   rapl_gpu_unit, "Joules");
+RAPL_EVENT_ATTR_STR(energy-cores.unit, rapl_cores_unit, "Joules");
+RAPL_EVENT_ATTR_STR(energy-pkg.unit  ,   rapl_pkg_unit, "Joules");
+RAPL_EVENT_ATTR_STR(energy-ram.unit  ,   rapl_ram_unit, "Joules");
+RAPL_EVENT_ATTR_STR(energy-gpu.unit  ,   rapl_gpu_unit, "Joules");
 
 /*
  * we compute in 0.23 nJ increments regardless of MSR
  */
-EVENT_ATTR_STR(energy-cores.scale, rapl_cores_scale, "2.3283064365386962890625e-10");
-EVENT_ATTR_STR(energy-pkg.scale,     rapl_pkg_scale, "2.3283064365386962890625e-10");
-EVENT_ATTR_STR(energy-ram.scale,     rapl_ram_scale, "2.3283064365386962890625e-10");
-EVENT_ATTR_STR(energy-gpu.scale,     rapl_gpu_scale, "2.3283064365386962890625e-10");
+RAPL_EVENT_ATTR_STR(energy-cores.scale, rapl_cores_scale, "2.3283064365386962890625e-10");
+RAPL_EVENT_ATTR_STR(energy-pkg.scale,     rapl_pkg_scale, "2.3283064365386962890625e-10");
+RAPL_EVENT_ATTR_STR(energy-ram.scale,     rapl_ram_scale, "2.3283064365386962890625e-10");
+RAPL_EVENT_ATTR_STR(energy-gpu.scale,     rapl_gpu_scale, "2.3283064365386962890625e-10");
 
 static struct attribute *rapl_events_srv_attr[] = {
 	EVENT_PTR(rapl_cores),