Triple Buffering

[Simon F]

I think it could be slightly higher. With double buffering, you can never be rendering more than 1.999 frames ahead, while it could be 2.999 frames for triple buffering.

I think.

It appears to be weirder than that! My lunch time programming/hacking may be wrong (it wouldn't surprise me), but it appears that sometimes with triple buffering the average latency is lower and at other times higher!. <shrug>

For example, a frame rendering time of 1.1 refreshes gets an average latency of ~ 1.6.

1.4999 -> 1.75
1.5 -> 2.25

I'm sooo glad I never studied queuing theory at Uni.

 

[incurable]

There's a good explanation of all this here

However, with triple buffering your input (mouse and keyboard) lags behind one frame compared to double buffering. The reason is the fact that with double buffering there is only one frame drawn beforehand that your input can't effect, but with triple buffering there are ususally two frames buffered. So, if your game plays at 50 fps, you usually have an input lag of 20 ms (at least) with double buffering, but with triple buffering you would have an input lag of 40 ms (at least).

Shameless quote from nVnews

I'm with Simon F here. The 50 fps example doesn't include the latency effects introduced by VSync which should be part of the evaluation. (triple buffering w/ VSync off seems rather useless, doesn't it?)

Alasly, having sitten in the sun for the past hour, I just can't seem to get myself to actually calc the numbers.

cu

incurable, waiting for the sunburn 8)

 

[Dio]

It appears to be weirder than that! My lunch time programming/hacking may be wrong (it wouldn't surprise me), but it appears that sometimes with triple buffering the average latency is lower and at other times higher!. <shrug>

Hmmm. Now I think about it this might well be right, because the time the frame spends in the 'wait state' might be more likely to be small... it probably varies greatly depending on the queue insertion and consumption rate.

I'm sooo glad I never studied queuing theory at Uni.

I'm right with you on that one.