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Given that's precisely the goal we were shooting for, this is considered done.
Note that Robin is investigating improving the generated code for the SATD routines. Esesntially we're doing a lot of byte loads when we should be loading larger values. This may provide a another small improvement on top of the basic vectorization.
Stakeholders/Partners
RISE:
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Updates
- Note additional opportunities for improvement.
- Testing on the k230 board shows "only" a 17% runtime improvement when the target for x264 vectorization is a 50% runtime improvement (which will double the spec score)
- However, it looks like the cost of a vector ALU op is at least 3X LMUL
- So a performant uarch where vector ALU ops of reasonable size (128 bits) are 1c would see the expected 50% runtime improvement.
- Considering this resolved.
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