Re: [Performance Timeline] Need higher resolution timers

On Mon, Aug 22, 2011 at 3:54 PM, Zhiheng Wang <zhihengw@google.com> wrote:

> However, looking longer term, there's a need for more precision. One
>> example is graphics, where milliseconds are already insufficient for
>> measuring frame rate.
>>
>
>    Do you have a more specific example?
>

If you measure frame rate by measuring the time between two subsequent
frames at millisecond resolution, you will get 58 or 62, but not 60.


>
>
>> Down the road, as games and apps get more sophisticated, we can expect
>> people to want to time things within a frame.
>>
>
>    IIRC, 50 msec is the threshold for human to detect any latency at all in
> FPS games. An app can still measure some other ops
> inside it. But overall, I am still not sure why an application really cares
> to know the exact sub-millisecond delay.
>

In order to display at 60 fps, an application must finish all of its work
within 16.7 ms. If we're talking about something as complicated as a game,
there's a lot of work to be done between frames. Physics, input, network,
sound, AI, graphics, etc. I expect developers will need higher resolution
than integer milliseconds for these. 1/16 is not much resolution.

James