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Instruction Throughput on Skylake
Author:  Date: 2016-07-08 02:50
T wrote:

Are you able to share your results about 5 or 6 wide throughput? You hinted at them in your post, but anything reproducible would be great.

All sharable, but I haven't been thinking about this direction for a couple months. I'll try to post something here if I can dig it up, but I won't be able to get to it immediately.

But if my recollection is correct, the short answer is that yes, Read-Modify instructions should almost always be used as heavily as possible for inner loops on modern Intel processors. They have significant upside if you would otherwise be limited by the renamer.

And while you say you are not interested in it, the corollary for micro-fusion is that CMP-JCC instructions should almost always be adjacent in assembly. I'm pretty sure that both GCC and LLVM would benefit from putting a higher penalty on the split.

 
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