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Message-Id: <1370968960-22527-14-git-send-email-rric@kernel.org>
Date: Tue, 11 Jun 2013 18:42:39 +0200
From: Robert Richter <rric@...nel.org>
To: Borislav Petkov <bp@...en8.de>
Cc: Ingo Molnar <mingo@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
Arnaldo Carvalho de Melo <acme@...radead.org>,
Jiri Olsa <jolsa@...hat.com>, linux-kernel@...r.kernel.org,
Robert Richter <robert.richter@...aro.org>,
Robert Richter <rric@...nel.org>
Subject: [PATCH v2 13/14] perf, persistent: Exposing persistent events using sysfs
From: Robert Richter <robert.richter@...aro.org>
Expose persistent events in the system to userland using sysfs. Perf
tools are able to read existing pmu events from sysfs. Now we use a
persistent pmu as an event container containing all registered
persistent events of the system. This patch adds dynamically
registration of persistent events to sysfs. E.g. something like this:
/sys/bus/event_source/devices/persistent/events/mce_record:persistent,config=106
/sys/bus/event_source/devices/persistent/format/persistent:attr5:23
Perf tools need to support the attr<num> syntax that is added in a
separate patch set. With it we are able to run perf tool commands to
read persistent events, e.g.:
# perf record -e persistent/mce_record/ sleep 10
# perf top -e persistent/mce_record/
[ Document attr<index> syntax in sysfs ABI ]
Reported-by: Jiri Olsa <jolsa@...hat.com>
Signed-off-by: Robert Richter <robert.richter@...aro.org>
Signed-off-by: Robert Richter <rric@...nel.org>
---
.../testing/sysfs-bus-event_source-devices-format | 43 ++++++++++++-----
kernel/events/persistent.c | 55 +++++++++++++++++++++-
2 files changed, 86 insertions(+), 12 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-bus-event_source-devices-format b/Documentation/ABI/testing/sysfs-bus-event_source-devices-format
index 77f47ff..47b7353 100644
--- a/Documentation/ABI/testing/sysfs-bus-event_source-devices-format
+++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-format
@@ -1,13 +1,14 @@
-Where: /sys/bus/event_source/devices/<dev>/format
+Where: /sys/bus/event_source/devices/<pmu>/format/<name>
Date: January 2012
-Kernel Version: 3.3
+Kernel Version: 3.3
+ 3.12 (added attr<index>:<bits>)
Contact: Jiri Olsa <jolsa@...hat.com>
-Description:
- Attribute group to describe the magic bits that go into
- perf_event_attr::config[012] for a particular pmu.
- Each attribute of this group defines the 'hardware' bitmask
- we want to export, so that userspace can deal with sane
- name/value pairs.
+
+Description: Define formats for bit ranges in perf_event_attr
+
+ Attribute group to describe the magic bits that go
+ into struct perf_event_attr for a particular pmu. Bit
+ range may be any bit mask of an u64 (bits 0 to 63).
Userspace must be prepared for the possibility that attributes
define overlapping bit ranges. For example:
@@ -15,6 +16,26 @@ Description:
attr2 = 'config:0-7'
attr3 = 'config:12-35'
- Example: 'config1:1,6-10,44'
- Defines contents of attribute that occupies bits 1,6-10,44 of
- perf_event_attr::config1.
+ Syntax Description
+
+ config[012]*:<bits> Each attribute of this group
+ defines the 'hardware' bitmask
+ we want to export, so that
+ userspace can deal with sane
+ name/value pairs.
+
+ attr<index>:<bits> Set any field of the event
+ attribute. The index is a
+ decimal number that specifies
+ the u64 value to be set within
+ struct perf_event_attr.
+
+ Examples:
+
+ 'config1:1,6-10,44' Defines contents of attribute
+ that occupies bits 1,6-10,44
+ of perf_event_attr::config1.
+
+ 'attr5:23' Define the persistent event
+ flag (bit 23 of the attribute
+ flags)
diff --git a/kernel/events/persistent.c b/kernel/events/persistent.c
index 96201c1..8be7c05 100644
--- a/kernel/events/persistent.c
+++ b/kernel/events/persistent.c
@@ -17,8 +17,10 @@ struct pers_event_desc {
struct pers_event {
char *name;
struct perf_event_attr attr;
+ struct perf_pmu_events_attr sysfs;
};
+static struct pmu persistent_pmu;
static DEFINE_PER_CPU(struct list_head, pers_events);
static DEFINE_PER_CPU(struct mutex, pers_events_lock);
@@ -137,6 +139,8 @@ unwind:
return PTR_ERR(event);
}
+static int pers_event_sysfs_register(struct pers_event *event);
+
int perf_add_persistent_event_by_id(char* name, int id)
{
struct pers_event *event;
@@ -150,6 +154,8 @@ int perf_add_persistent_event_by_id(char* name, int id)
if (!event->name)
goto fail;
+ event->sysfs.id = id;
+
attr = &event->attr;
attr->sample_period = 1;
attr->wakeup_events = 1;
@@ -163,6 +169,8 @@ int perf_add_persistent_event_by_id(char* name, int id)
if (ret)
goto fail;
+ pers_event_sysfs_register(event);
+
return 0;
fail:
kfree(event->name);
@@ -207,12 +215,57 @@ static struct attribute_group persistent_format_group = {
.attrs = persistent_format_attrs,
};
+#define MAX_EVENTS 16
+
+static struct attribute *persistent_events_attr[MAX_EVENTS + 1] = { };
+
+static struct attribute_group persistent_events_group = {
+ .name = "events",
+ .attrs = persistent_events_attr,
+};
+
static const struct attribute_group *persistent_attr_groups[] = {
&persistent_format_group,
+ NULL, /* placeholder: &persistent_events_group */
NULL,
};
+#define EVENTS_GROUP (persistent_attr_groups[1])
-static struct pmu persistent_pmu;
+static ssize_t pers_event_sysfs_show(struct device *dev,
+ struct device_attribute *__attr, char *page)
+{
+ struct perf_pmu_events_attr *attr =
+ container_of(__attr, struct perf_pmu_events_attr, attr);
+ return sprintf(page, "persistent,config=%lld",
+ (unsigned long long)attr->id);
+}
+
+static int pers_event_sysfs_register(struct pers_event *event)
+{
+ struct device_attribute *attr = &event->sysfs.attr;
+ int idx;
+
+ *attr = (struct device_attribute)__ATTR(, 0444, pers_event_sysfs_show,
+ NULL);
+ attr->attr.name = event->name;
+
+ /* add sysfs attr to events: */
+ for (idx = 0; idx < MAX_EVENTS; idx++) {
+ if (!cmpxchg(persistent_events_attr + idx, NULL, &attr->attr))
+ break;
+ }
+
+ if (idx >= MAX_EVENTS)
+ return -ENOSPC;
+ if (!idx)
+ EVENTS_GROUP = &persistent_events_group;
+ if (!persistent_pmu.dev)
+ return 0; /* sysfs not yet initialized */
+ if (idx)
+ return sysfs_update_group(&persistent_pmu.dev->kobj,
+ EVENTS_GROUP);
+ return sysfs_create_group(&persistent_pmu.dev->kobj, EVENTS_GROUP);
+}
static int persistent_pmu_init(struct perf_event *event)
{
--
1.8.1.1
--
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