diff options
| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2009-05-05 17:50:23 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-05-05 20:18:31 +0200 |
| commit | 6de6a7b95705b859b61430fa3afa1403034eb3e6 (patch) | |
| tree | 29214ae667a58aa005d0ed13e51c265fa675adf0 | |
| parent | c66de4a5be7913247bd83d79168f8e4420c9cfbc (diff) | |
perf_counter: add ioctl(PERF_COUNTER_IOC_RESET)
Provide a way to reset an existing counter - this eases PAPI
libraries around perfcounters.
Similar to read() it doesn't collapse pending child counters.
[ Impact: new perfcounter fd ioctl method to reset counters ]
Suggested-by: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20090505155437.022272933@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | include/linux/perf_counter.h | 1 | ||||
| -rw-r--r-- | kernel/perf_counter.c | 8 |
2 files changed, 9 insertions, 0 deletions
diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h index 17b63105f2a..0fcbf34a4f7 100644 --- a/include/linux/perf_counter.h +++ b/include/linux/perf_counter.h @@ -160,6 +160,7 @@ struct perf_counter_hw_event { #define PERF_COUNTER_IOC_ENABLE _IO ('$', 0) #define PERF_COUNTER_IOC_DISABLE _IO ('$', 1) #define PERF_COUNTER_IOC_REFRESH _IOW('$', 2, u32) +#define PERF_COUNTER_IOC_RESET _IO ('$', 3) /* * Structure of the page that can be mapped via mmap diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index ba5e921e1f3..6e6834e0587 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -1288,6 +1288,11 @@ static unsigned int perf_poll(struct file *file, poll_table *wait) return events; } +static void perf_counter_reset(struct perf_counter *counter) +{ + atomic_set(&counter->count, 0); +} + static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { struct perf_counter *counter = file->private_data; @@ -1303,6 +1308,9 @@ static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg) case PERF_COUNTER_IOC_REFRESH: perf_counter_refresh(counter, arg); break; + case PERF_COUNTER_IOC_RESET: + perf_counter_reset(counter); + break; default: err = -ENOTTY; } |