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Old 02-Jan-2013, 17:55   #25
OpenGL guy
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Quote:
Originally Posted by Andrew Lauritzen View Post
As I've mentioned in previous responses, I wasn't referencing the AMD issue there specifically, just using examples of why FPS is a bad metric.
Yep, I know. I was just saying that "avoiding all hitches" isn't practical in some cases, at least with current APIs.
Quote:
Originally Posted by Andrew Lauritzen
Right, i.e. "state-based recompiles", but these get nastier than just fixed-function features. Still like changing certain rasterizer/blend state, bound texture types (2D/3D/Cube/etc) and so on can also cause recompiles and the state that is "dynamic" vs. "compiled" is implementation dependent and completely opaque. ... and it definitely does happen in the middle of gameplay.

This sort of stuff has to stop in the long run, but it implies more general hardware and people don't want to pay the price.
More general hardware implies more recompilation, not less. It's the removal of fixed-function bits that trigger some of these things.
Quote:
Originally Posted by Andrew Lauritzen
But yeah, to reiterate, I'm not claiming that's what's happening here (it's probably more memory-related stuff, as usual), but it's yet another "hitch/stutter" that is ignored when measuring using FPS.
This is one issue with benchmarking. Getting a hitch on the first instance of a new effect might be annoying, but if you're using those same effects for the next 30 minutes, who will remember the hitch that happened 29 minutes ago?
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