we have an issue with our HP XL230a Gen9 blades where some of the applications are only seeing half of the CPU. On the task manager we see all 56 cores but application are only seeing half of them. We also see half CPU on NUMBER_OF_PROCESSORS=28 environment variable.

we enabled node interleaving in the BIOS and that fixed our issue i.e. all apps can see all 56 cores

The issue can be seen on both Hyperthreaded and Non hyperthreaded blades (windows 2008 r2 and windows 2012) and enabling node interleaving fixes the issue.

I found a C++ example which uses GetSystemInfo() and GetNativeSystemInfo() methods to get the available core and that too is showing only 28 when Node interleaving is disabled.

We have also applied the latest available firmware/bios update but still the same. We are contacting HP about this but just wanted to know if other people have seen anything like this and if there is a way to fix it with node interleaving=disabled?



It seems like people are having NUMA issues under Microsoft operating systems with this new ProLiant hardware. I'd be curious if other vendors (Dell/IBM) are seeing this with the Intel E5 v3 processors.

Please see the comments and answers at:

Unable to use more than one processor group for my threads in a C# app


How is NUMBER_OF_PROCESSORS env variable generated?

Basically, upgrade firmware to the 1.30_12-24-2014(30 Mar 2015) revision.

  • Thanks ewwhite. HP just told us that they will fix this in the next BIOS update. – Fahad Mar 11 '15 at 15:40

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