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On 08/21/2010 03:27 PM, Lu, Hongjiu wrote: >> >>> What is the performance impact of extra function call >>> vs. multiple copies of the same jump table? >> >> I don't know. I would hope that an indirect call and return >> would be just as predictable as an indirect jump and branch. >> >> Fancy helping me benchmark? >> > > Sure. Send me a patch. I will run some benchmarks. And for good measure, here's a third patch which implements a variable shift via pshufb. Which means we avoid any control mis-prediction in favor of a data load stall. Whether this is better or worse given a large insn re-order buffer, I have no idea. Something else to test. r~
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