perf_counter: counter overflow limit
Provide means to auto-disable the counter after 'n' overflow events.
Create the counter with hw_event.disabled = 1, and then issue an
ioctl(fd, PREF_COUNTER_IOC_REFRESH, n); to set the limit and enable
the counter.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
LKML-Reference: <20090406094518.083139737@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h
index 928a7fa..ef4dcbf 100644
--- a/include/linux/perf_counter.h
+++ b/include/linux/perf_counter.h
@@ -155,8 +155,9 @@
/*
* Ioctls that can be done on a perf counter fd:
*/
-#define PERF_COUNTER_IOC_ENABLE _IO('$', 0)
-#define PERF_COUNTER_IOC_DISABLE _IO('$', 1)
+#define PERF_COUNTER_IOC_ENABLE _IO ('$', 0)
+#define PERF_COUNTER_IOC_DISABLE _IO ('$', 1)
+#define PERF_COUNTER_IOC_REFRESH _IOW('$', 2, u32)
/*
* Structure of the page that can be mapped via mmap
@@ -403,9 +404,14 @@
/* poll related */
wait_queue_head_t waitq;
struct fasync_struct *fasync;
- /* optional: for NMIs */
+
+ /* delayed work for NMIs and such */
+ int pending_wakeup;
+ int pending_disable;
struct perf_pending_entry pending;
+ atomic_t event_limit;
+
void (*destroy)(struct perf_counter *);
struct rcu_head rcu_head;
#endif