How to make Java application use all CPU groups
<p>I am running a java application on Intel(R) Xeon(R) machine which has 72 CPUs (with Hyperthreading on). Since, Microsoft groups CPUs into two groups if there are more than 64 CPUs, the java application uses only 1 group (or in other words 36 CPUs). See the snapshots below for the grouping and CPU usage details. As we can see, the java application is using 36 CPUs at capacity but not able to use other CPUs.</p>

<p><a href="https://i.stack.imgur.com/AVm58.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/AVm58.png" alt="enter image description here"></a></p>

<p><a href="https://i.stack.imgur.com/T8GjD.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/T8GjD.png" alt="enter image description here"></a></p>

<p>I added +UseNUMA in JVM parameters but it did not work. Does anyone know of JVM option to make it use all CPU groups?</p>

<p>The windows server machine has 72 CPUs after hyperthreading. Windows, by default, groups the CPUs into two memory nodes if number of CPUs are more than 64 (<a href="https://msdn.microsoft.com/en-us/library/dd405503(VS.85).aspx" rel="nofollow noreferrer">https://msdn.microsoft.com/en-us/library/dd405503(VS.85).aspx</a>). Java application uses only 1 nodes and thus not using the computer at capacity. I enabled node-interleaving but it didn't help either. So, my question is if there is a way to span Java application over multiple memory nodes.</p>