STREAM questions on A64FX

[Yan Kang]

Hi all, 

I am trying to get read & write memory data volume of STREAM benchmark on Ookami (A64FX machine), 

Likwid version: 5.1.1

Here is the running command I used:

     likwid-perfctr -c 0-47 -g MEM ./stream

However, I found in the results, there are only four cores(0, 12, 24 and 36) that did all the read and write, every cores else are showing 0s. Which is bit Odd. I am not sure if that is because of my running command is not correct. 

Can anyone please help? 

Best, 

Yan

 

   

[Thomas Gruber]

Hi,

the memory events BUS_READ_TOTAL_MEM and BUS_WRITE_TOTAL_MEM are CMG specific, so only one hardware thread in the CMG measures the counts, they reflect the traffic caused by all hardware threads of the CMG.

But there was an errata published by Fujitsu that these two events are not accurate. The latest version of the MEM group uses different events which count per hardware thread. Please update your installation (or at least the MEM group) and try again.

Best,
Thomas