Re: [PATCH 1/5] perf core: Introduce new ioctl options to pause and resume ring buffer

From: Michael Kerrisk (man-pages)
Date: Fri Oct 21 2016 - 03:06:14 EST


Hello Wangnan,

The patch below seems to have landed in Linux 4.7,
commit 86e7972f690c1017fd086cdfe53d8524e68c661c

Could you draft a man-pages patch for this interface
change, please? Or, failing that, a plain-text
description that we can integrate into the man-page.

Thanks,

Michael

On 03/23/2016 10:33 AM, Wangnan (F) wrote:
>
>
> 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.
>
>
>


--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/