Not all cores are active during test

[Chamjisky]

Hi i have memtest86 4.3.7 and testing 72gb, 8 sticks each of 8 gb using dell t5500 workstation using dual L5630 processors in parallel mode but instead of using 16 threads/8cores it is just using 2 cores.


Even if I remove second processor from system it just shows one core instead of 4 cores in parallel mode
.

I am using latest a16 bios.


It's not UEFI system.
Hyper threading and virtualization enabled.

[keith]

Can you run MemTest86 v4 in boot trace mode from the menu and if possible, record a video of each boot step until the test starts.

[Chamjisky]

Will do it after I reach home after 6 hours

[Chamjisky]

I also noticed that memtest hasn't detected L1, L2 cache

[Chamjisky]

I resolved it by disabling limited cpu id option in bios under performance.
But with hyper threading enabled instead of 16 threads it is using just 8.

Is it normal and ok?

[keith]

Enabling the 'Limit CPUID' option will prevent MemTest86 from obtaining the necessary information regarding the number of CPU cores/threads, so it makes sense that disabling it would fix the problem.

MemTest86 can only run on physical cores and not hyperthreads so yes it is normal to see the number of CPUs running is less than the number of CPUs found.

[Chamjisky]

Thanks my issue is resolved. Hope it would benefit someone.

[abufrejoval]

Enabling the 'Limit CPUID' option will prevent MemTest86 from obtaining the necessary information regarding the number of CPU cores/threads, so it makes sense that disabling it would fix the problem.

MemTest86 can only run on physical cores and not hyperthreads so yes it is normal to see the number of CPUs running is less than the number of CPUs found.

I guess v7 beta behaves differently?

On a 4 core Xeon with 8 HT I see all threads active with the first being "off cycle" with the spinning hyphens and dashes.

On a 12 core Xeon with 24 HT I see 7 thread left in waiting state. I also believe it started with perhaps 8 threads and then switched to 1 "off-cycle" (control?) thread and 16 workers(?)

[abufrejoval]

Just noticed, those 16 worker threads seem to be a limitation in Rowhammer, only. Other multicore tests use all available threads von v7.

[keith]

In the row hammer test, the memory segments are divided equally amongst all CPUs only if the amount of memory assigned to each CPU is sufficient to perform row hammering. Otherwise, only a subset of the CPUs are used.