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These developments are quite funny. At one point GPUs were just fixed function hardware. As more flexibility was needed for novel applications, programmability

These developments are quite funny. At one point GPUs were just fixed function hardware. As more flexibility was needed for novel applications, programmability was added. Now we are going to back to fixed function units as the calculus has changed in favour of power savings and against flexibility. I'm interesting in seeing what advance in tech will change it again in favour of flexibility.

ttoinou 9y ago
Maybe because we are mixing up concepts and names ? You are comparing GPUs that were on tower computers and GPU that are now on mobile computers. Like you said, mobile require energy efficiency so having a fixed function chip makes sense right now, just like it made sense for tower computers back then.
photojosh 9y ago
> the calculus has changed in favour of power savings and against flexibility This has always been a trade-off. For instance even with desktops, once video handling became common we first had video decode/encode being handled by GPU acceleration. But now most CPUs include dedicated h264 (and more recently hevc) decode/encode support, eg [0]. Although it's much lower computation, hardware acceleration is also offered for audio, and I'd take a guess the reason the Apple APIs for checking which hardware supports hardware-based audio encode/decode [1] has been deprecated is now because all supported devices provide all possible capabilities. [0]: https://en.wikipedia.org/wiki/Intel_Quick_Sync_Video https://en.wikipedia.org/wiki/Intel_Quick_Sync_Video [1]: https://developer.apple.com/documentation/audiotoolbox/1620452-hardware_codec_capabilities?language=objc https://developer.apple.com/documentation/audiotoolbox/16204...
- TD-Linux 9y ago
  In the case with audio, it might be the opposite - even with a modern audio codec like Opus, an Apple CPU can decode an entire song into RAM in a fraction of a second. At that point, the CPU has to wake up anyway to download another song from Spotify or read one from disk.

ttoinou 9y ago

Maybe because we are mixing up concepts and names ? You are comparing GPUs that were on tower computers and GPU that are now on mobile computers. Like you said, mobile require energy efficiency so having a fixed function chip makes sense right now, just like it made sense for tower computers back then.

photojosh 9y ago

> the calculus has changed in favour of power savings and against flexibility This has always been a trade-off. For instance even with desktops, once video handling became common we first had video decode/encode being handled by GPU acceleration. But now most CPUs include dedicated h264 (and more recently hevc) decode/encode support, eg [0]. Although it's much lower computation, hardware acceleration is also offered for audio, and I'd take a guess the reason the Apple APIs for checking which hardware supports hardware-based audio encode/decode [1] has been deprecated is now because all supported devices provide all possible capabilities. [0]: https://en.wikipedia.org/wiki/Intel_Quick_Sync_Video https://en.wikipedia.org/wiki/Intel_Quick_Sync_Video [1]: https://developer.apple.com/documentation/audiotoolbox/1620452-hardware_codec_capabilities?language=objc https://developer.apple.com/documentation/audiotoolbox/16204...

TD-Linux 9y ago
In the case with audio, it might be the opposite - even with a modern audio codec like Opus, an Apple CPU can decode an entire song into RAM in a fraction of a second. At that point, the CPU has to wake up anyway to download another song from Spotify or read one from disk.