affinity only support 64 cores?

Started by aardvark0, October 10, 2019, 05:24:24 PM

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Lasso detects the processors correctly at the bottom of the main window - 4 NUMA nodes, 60/120 cores
Trying to Set CPU affinity of an App only displays 0-59 cores that can be selected, not 120
Choosing disable hyper-threading, disables only every other core of the first 60.
using Win 10 for Workstations
would like to keep hyperthreading enabled, and disable hyperthreaded cores for apps that do not support processor groups.

Jeremy Collake

There is no good solution for you. You would need to disable Hyper-Threading for the whole system.

By Windows design, the CPU affinity represents only CPUs in a single processor group (at most 64 cores). It can't span multiple groups.

The CPU affinity applies to whatever the default processor group for that app instance is. So if you set a CPU affinity of 0-4, that would be the first 4 logical cores of whatever group the application was started on.

I wrote about the 64 core threshold here.
Software Engineer. Bitsum LLC.

Jeremy Collake

Process Lasso 9.7 adds the Processor Group Extender. This novel algorithm allows processor group unaware applications to make use of the full CPU. It accomplishes this by monitoring threads of target processes and dynamically assigning threads to supplemental processor groups.

If you have any group unaware applications that you'd like to enable use of the entire CPU, give it a try.

Note that there is still a lot of additional GUI work surrounding processor groups, including being able to display per-core utilization of more than one.


Demo video:

Software Engineer. Bitsum LLC.