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by gcp 3402 days ago
Ah, but what should they benchmark GEMM with?

MKL? I don't think so, it takes the worst codepath if the chip isn't GenuineIntel. OpenBLAS? Doesn't have Ryzen support. Doesn't even recognize some AMD cores. ACML? Wasn't updated since 2013 or so.

This is a serious question. What are you supposed to do if you need a GEMM kernel for Ryzen? I sure hope AMD puts out updated ACML libraries real soon.
1 comments
philipkglass 3402 days ago
I'd like to see benchmarks with OpenBLAS. Unlike ACML it's under active development, unlike MKL it won't deliberately screw AMD performance, and it offers "pretty good" performance across every environment I've tried it in. Good enough that it's not worth paying for MKL, not worth going through ATLAS's self-tuning routine, not worth changing my build scripts to use vecLib under OS X. If OpenBLAS currently runs poorly on Ryzen I hope Ryzen will get some development love, because I kind of hate using ATLAS and at this point it would take a major advantage to tempt me back away from open source components.
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timeu 3402 days ago
Word! I think AMD should focus on OpenBLAS and add support for their new CPUs there. OpenBLAS is part of the foss toolchain for the easybuild easyconfig. So for the HPC field adding support to OpenBLAS would be great.

I would also need to update this benchmark (if I can get hold of the new AMD CPUs) ;-) http://stackoverflow.com/questions/5260068/multithreaded-bla...

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gcp 3402 days ago
OpenBLAS performance is atrocious in 32 bit mode because it doesn't properly support AVX with the halved register file. Not the most common configuration, but MKL handles it fine (on Intel chips, obviously).

That said I agree it makes more sense for AMD to contribute to OpenBLAS than anything else.

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philipkglass 3402 days ago
Interesting -- what are the use cases for single precision BLAS on CPU? All the scientific software I use requires double precision and for tasks that do well with single precision, I would have thought that GPGPU would now be the go-to solution.
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gcp 3402 days ago
Not if you're shipping software to consumers. (Also, I actually meant 32-bit as in the OS, not the floating point precision)
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