unique id for wayland objects

[zou lan]

Hi pekka

I test presentation on my side. The presentation results is not accurate
because our pageflip event send last frame's timestamp every time. So
weston_output_finish_frame send last frame's present tine
to current frame's feedback. For this situation, I just delay one frame to
send present event. Does this get the right c2p time? Thank you.

Best Regards
Nancy

2018-05-02 18:17 GMT+08:00 zou lan <nancy.lan.zou at gmail.com>:

> Hi pekka
>
> Thank you for your clearly analysis. I understand the presentation
> protocol is enough for the requirement now.
>
> I used to not study the protocol deeply because the code is a little more
> than just record the flip timestamp. The
> test want to do this as simple as possible.
>
> I will try the presentation first. Thank you!
>
> Best Regards
> Nancy
>
> 2018-05-02 16:59 GMT+08:00 Pekka Paalanen <ppaalanen at gmail.com>:
>
>> On Wed, 2 May 2018 16:33:43 +0800
>> zou lan <nancy.lan.zou at gmail.com> wrote:
>>
>> > Add to wayland mail list.
>> >
>> > Hi pekka
>> >
>> > I used to consider the time line and presentation protocol. But they are
>> > all focus on surface, not buffer. The test want to know the buffer
>> latency,
>> > although they are the same as surface's on
>> > most cases. Applications think maybe some buffers doesn't display and
>> used
>> > again.
>> >
>> > By the way, could add a event to wl_buffer's protocol achieve the
>> > requirement? Thank you.
>>
>> Hi Nancy,
>>
>> when a client creates a wp_presentation_feedback object, that object
>> tracks the particular wl_surface.commit carrying an attached wl_buffer.
>> So it is specific to the particular commit, not just to the surface
>> or even to the buffer (buffers get re-used or could theoretically be
>> used on multiple surfaces).
>>
>> Can you not have the client record both the current time at sending
>> wl_surface.commit and the corresponding timestamp it gets from
>> wp_presentation_feedback? Why would this not be enough?
>>
>> Please, see clients/presentation-shm.c in the Weston repository for an
>> example that tracks this kind of presentation latencies.
>>
>>
>> Thanks,
>> pq
>>
>> > ---------- Forwarded message ----------
>> > From: Pekka Paalanen <ppaalanen at gmail.com>
>> > Date: 2018-05-02 15:48 GMT+08:00
>> > Subject: Re: unique id for wayland objects
>> > To: zou lan <nancy.lan.zou at gmail.com>
>> >
>> >
>> > On Wed, 2 May 2018 10:57:17 +0800
>> > zou lan <nancy.lan.zou at gmail.com> wrote:
>> >
>> > > Hi pekka
>> > >
>> > > I want to get the accurate buffer latency from a buffer commit by
>> client
>> > to
>> > > display on the screen. The client can get the timestamp when buffer
>> commit
>> > > and release. So weston only need to give a
>> > > timestamp when call on_pageflip.
>> > >
>> > > When do the real time analysis, there are many clients,  I want to
>> use one
>> > > unique id to distinguish from each other quickly.
>> >
>> > Hi,
>> >
>> > is there any reason you don't use presentation_feedback interface? To
>> > me it sounds like that would provide exactly what you need.
>> >
>> > https://cgit.freedesktop.org/wayland/wayland-protocols/
>> > tree/stable/presentation-time
>> >
>> > Also, could we have this coversation on the mailing list, please?
>> >
>> >
>> > Thanks,
>> > pq
>>
>>
>
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