Provide a way to reset an existing counter. Similar to read() it doesn't collapse pending child counters. Signed-off-by: Peter Zijlstra --- include/linux/perf_counter.h | 1 + kernel/perf_counter.c | 8 ++++++++ 2 files changed, 9 insertions(+) Index: linux-2.6/include/linux/perf_counter.h =================================================================== --- linux-2.6.orig/include/linux/perf_counter.h +++ linux-2.6/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 Index: linux-2.6/kernel/perf_counter.c =================================================================== --- linux-2.6.orig/kernel/perf_counter.c +++ linux-2.6/kernel/perf_counter.c @@ -1288,6 +1288,11 @@ static unsigned int perf_poll(struct fil 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 case PERF_COUNTER_IOC_REFRESH: perf_counter_refresh(counter, arg); break; + case PERF_COUNTER_IOC_RESET: + perf_counter_reset(counter); + break; default: err = -ENOTTY; } -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/