[dman]

Just built a 64 core workstation based on AMD Epyc cpus, seeing how fast my simulation workloads run on it brings a smile to my face.

[effie]

I can appreciate the fun to be had with so many core cpu, but did you actually measure the performance? According to Passmark, both single and multithread performance of EPYC is very poor [1][2]. Passmark database is years in building and very informative, but I think for EPYC that is an erroneous result. Could you run Passmark benchmark on your rig to get another data point public?

[1] https://www.cpubenchmark.net/cpu.php?cpu=AMD+EPYC+7501&id=31...

[2] Compare that with performance and price of something like E5-2670 from 2012: https://www.cpubenchmark.net/cpu.php?cpu=Intel+Xeon+E5-2670+...

[dman]

Will give that a try tonight. Have to warn you that right now 1 of my DIMM was bad, so the system is running with only 15 DIMMS (which is an unsupported config) so the results might be suboptimal until I receive a new DIMM from the seller.

[effie]

That's great, looking forward to the results. But, there's no rush. If you'd like to measure today anyway, please just make sure the result doesn't get reported to Passmark database so as not to spoil the small dataset with a biased result. Good luck with the replacement, hope it will stay solid from now on.

[dman]

Just realised that Passmark does not have a Linux benchmark program, so wont be able to run it.

[effie]

Ah, that's a shame. I'd love to know how much faster the Epyc is than the E5-2670. Could you try to run sysbench to get some numbers? Here are mine:

# sysbench --test=cpu run --max-requests=20000 Test execution summary: total time: 25.9014s total number of events: 20000 total time taken by event execution: 25.8983 per-request statistics: min: 1.27ms avg: 1.29ms max: 3.19ms approx. 95 percentile: 1.29ms

# sysbench --test=cpu run --max-requests=20000 --num-threads=16 Test execution summary: total time: 1.6859s total number of events: 20000 total time taken by event execution: 26.9264 per-request statistics: min: 1.26ms avg: 1.35ms max: 3.59ms approx. 95 percentile: 1.51ms

[dman]

[dman@epyc ~]$ sysbench --test=cpu run --max-requests=20000 WARNING: the --test option is deprecated. You can pass a script name or path on the command line without any options. WARNING: --max-requests is deprecated, use --events instead sysbench 1.0.14 (using bundled LuaJIT 2.1.0-beta2)

Running the test with following options: Number of threads: 1 Initializing random number generator from current time

Prime numbers limit: 10000

Initializing worker threads...

Threads started!

CPU speed: events per second: 1461.82

General statistics: total time: 10.0004s total number of events: 14621

Latency (ms): min: 0.67 avg: 0.68 max: 1.76 95th percentile: 0.69 sum: 9997.72

Threads fairness: events (avg/stddev): 14621.0000/0.00 execution time (avg/stddev): 9.9977/0.00

[dman@epyc ~]$ sysbench --test=cpu run --max-requests=20000 --num-threads=128 WARNING: the --test option is deprecated. You can pass a script name or path on the command line without any options. WARNING: --num-threads is deprecated, use --threads instead WARNING: --max-requests is deprecated, use --events instead sysbench 1.0.14 (using bundled LuaJIT 2.1.0-beta2)

Running the test with following options: Number of threads: 128 Initializing random number generator from current time

Prime numbers limit: 10000

Initializing worker threads...

Threads started!

CPU speed: events per second: 47980.46

General statistics: total time: 0.4152s total number of events: 20000

Latency (ms): min: 0.68 avg: 2.06 max: 111.24 95th percentile: 3.36 sum: 41275.73

Threads fairness: events (avg/stddev): 156.2500/118.37 execution time (avg/stddev): 0.3225/0.06

Let me know if you want me to run any other benchmarks.