Help needed: Ampere 128 core vs Ampere 96 core; Jeff Geerling Performance Testing

Wondering if someone in the community might know the answer to this or know someone with an answer.

From @geerlingguy github issue:

I’ve bumped Ps/Qs, and tweaked Ns a bit, but for some reason on my system, I can’t get the M128-28 CPU I swapped in to get any higher number than my M96-28 CPU…
I have kept everything else in the system identical (same Samsung 96 GB RAM, no additional PCIe cards, same USB network adapter plugged in, using VGA monitor output), but with the M128-28 CPU, I changed HPL.dat to use:

N: 100000
NB: 256
P: 8
Q: 16

That resulted in 1118.5 Gflops, nearly identical to the 96-core result. I installed lm-sensors and ran watch sensors, and the SoC temp never rose above 65-67°C. CPU power hovered around 125-130W, and never went any higher. Checking cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_cur_freq, almost all cores were locked at 2800000, but maybe 10-15 would go up and down."

GitHub Issue Link: M128-28 not getting better scores than M96-28 · Issue #11 · AmpereComputing/HPL-on-Ampere-Altra · GitHub

@avladu @bexcran @Manawyrm @q66 @pzc @hrw or anyone else?


No idea. Never used Ampere system.