On our Windows Server 2019, we have 36 cores and 72 logical processors, as seen in Task Manager CPU performance window. And, also, if from command prompt, if I run the command.
echo %NUMBER_OF_PROCESSORS%
It tells me 72.
However, from within Java program, if I run the following code snippet,
int cores = Runtime.getRuntime().availableProcessors();
String procrs = System.getenv("NUMBER_OF_PROCESSORS");
the value of cores and procrs show me, as 36, each.
Same system variable, NUMBER_OF_PROCESSORS is showing me different result from a command prompt vs from within Java program. Why?
I understand, the system variable, NUMBER_OF_PROCESSORS gets automatically set and does not need to be manually intervened ever. Microsoft documentation link on processor groups stated that:
Support for systems that have more than 64 logical processors is based on the concept of a processor group, which is a static set of up to 64 logical processors that is treated as a single scheduling entity. Processor groups are numbered starting with 0. Systems with fewer than 64 logical processors always have a single group, Group 0.
Is this the reason of showing me 36 from within my Java code snippet?