RE: [Algorithms] lights/shadows rendering architecture
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From: Tom F. <tom...@ee...> - 2005-09-24 03:25:19
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True, but it is a place where the GPU hardware is not working as hard as = it could, so if you're limited by GPU performance, it's going to hurt your frames-per-second. The other thing to consider is that some hardware can't do this stall itself, it needs CPU assistance to help it. Which means it IS a CPU-GPU = sync point! Fortunately, that sort of hardware seems to be less common these days. TomF. > -----Original Message----- > From: gda...@li...=20 > [mailto:gda...@li...] On=20 > Behalf Of Jon Watte > Sent: 23 September 2005 13:23 > To: gda...@li... > Subject: Re: [Algorithms] lights/shadows rendering architecture >=20 >=20 >=20 > > There is only 1 GPU, but they have very long pipelines, and=20 > they also do a > > lot of things in parallel. So the front of the pipeline can=20 > be trying to use > > the texture before the end of it has finished, which it=20 > can't do, so it has > > to stall. >=20 > But this is a "fake" stall -- more like a pipeline bubble.=20 > The CPU still=20 > keeps feeding stuff into the queue, so there's no GPU/CPU=20 > synchronization stall. Meanwhile, the GPU still keeps working without=20 > going idle (although some specific functional unit might be=20 > idle for a=20 > little while -- hence, the "bubble"). >=20 > I guess how bad that is depends entirely on your GPU and your scene... >=20 > Cheers, >=20 > / h+ >=20 >=20 > --=20 > -- The early bird gets the worm, but the second mouse gets the cheese. |