zafena development

March 9, 2010


I have from time to time been working on a automatic CPU feature tuning code for Shark to make the LLVM JIT generate better code for Cortex-A8 class ARM CPUs. Using it i was able to gain some substantial speed-improvements, all in all it made Shark generate 30% faster code on ARM and the Shark JIT are now able to beat the 2000 point CaffeineMark 3.0 score! I could not resist using CaffeineMark 3.0 for some benchmarking again :) .

While this looks all great with rainbows and unicorns the patch are sadly in limbo. I have had some trouble merging the code into LLVM 2.7 trunk before the next LLVM release since I got hit by LLVM problem report 6544 that will force me to redesign the implementation on top of LLVM before it can be commited.

And a similar optimisation like what i did for ARM Linux can easily be done for Shark on PPC Linux as well by adopting the ARM CPU features detection code from ARM to PPC!
For those who are interested the optimising code are submitted and can be fetched from LLVM PR5389.

Cheers and have a great day!
Xerxes

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