[Beowulf] AMD and AVX512

Prentice Bisbal pbisbal at pppl.gov
Wed Jun 16 17:15:40 UTC 2021

Did anyone else attend this webinar panel discussion with AMD hosted by 
HPCWire yesterday? It was titled "AMD HPC Solutions: Enabling Your 
Success in HPC"


I attended it, and noticed there was no mention of AMD supporting 
AVX512, so during the question and answer portion of the program, I 
asked when AMD processors will support AVX512. The answer given, and I'm 
not making this up, is that AMD listens to their users and gives the 
users what they want, and right now they're not hearing any demand for 

Personally, I call BS on that one. I can't imagine anyone in the HPC 
community saying "we'd like processors that offer only 1/2 the floating 
point performance of Intel processors". Sure, AMD can offer more cores, 
but with only AVX2, you'd need twice as many cores as Intel processors, 
all other things being equal.

Last fall I evaluated potential new cluster nodes for a large cluster 
purchase using the HPL benchmark. I compared a server with dual AMD EPYC 
7H12 processors (128) cores to a server with quad Intel Xeon 8268 
processors (96 cores). I measured 5,389 GFLOPS for the Xeon 8268, and 
only 3,446.00 GFLOPS for the AMD 7H12. That's LINPACK score that only 
64% of the Xeon 8268 system, despite having 33% more cores.

 From what I've heard, the AMD processors run much hotter than the Intel 
processors, too, so I imagine a FLOPS/Watt comparison would be even less 
favorable to AMD.

An argument can be made that for calculations that lend themselves to 
vectorization should be done on GPUs, instead of the main processors but 
the last time I checked, GPU jobs are still memory is limited, and 
moving data in and out of GPU memory can still take time, so I can see 
situations where for large amounts of data using CPUs would be preferred 
over GPUs.

Your thoughts?


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