On 2016/3/23 17:16, Peter Zijlstra wrote:
On Mon, Mar 14, 2016 at 09:59:41AM +0000, Wang Nan wrote:Add new ioctl() to pause/resume ring-buffer output. In some situations we want to read from ring buffer only when we ensure nothing can write to the ring buffer during reading. Without this patch we have to turn off all events attached to this ring buffer to achieve this. This patch is for supporting overwrite ring buffer. Following commits will introduce new methods support reading from overwrite ring buffer. Before reading caller must ensure the ring buffer is frozen, or the reading is unreliable. diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index 1afe962..a3c1903 100644 --- a/include/uapi/linux/perf_event.h +++ b/include/uapi/linux/perf_event.h @@ -401,6 +401,7 @@ struct perf_event_attr { #define PERF_EVENT_IOC_SET_FILTER _IOW('$', 6, char *) #define PERF_EVENT_IOC_ID _IOR('$', 7, __u64 *) #define PERF_EVENT_IOC_SET_BPF _IOW('$', 8, __u32) +#define PERF_EVENT_IOC_PAUSE_OUTPUT _IOW('$', 9, __u32)
Glad to see you start to look at this patchset.
Can you also do a patch to the man-pages? http://man7.org/linux/man-pages/man2/perf_event_open.2.html
Sure. I think I need to provide a patch for: http://git.kernel.org/cgit/docs/man-pages/man-pages.git But which one should be the first? Shall we update man pages before this patch be merged by upstream? Or Michael and Vince will consider this problem? Thank you.
