Am Mittwoch, dem 16.04.2025 um 16:37 +0000 schrieb Ralph Stirling via Emc-users: > It said four cores before I applied all the kernel parameters in the > linked document. I think it is the kthread_cpus line that assigns > two cores to non-realtime tasks and the isolcpus line that assigns > only realtime tasks to the remaining two cores. The parameters > did substantially improve latency. > > I went ahead and commented out the grub changes and sysctl > changes and ran latency histogram again. You can see the four > cores and zero isolcpus. >
Your CPU has 2 cores and each core has 2 (hyper-) threads. That presents as a 4-core machine to the OS. Except if you disable hyperthreading, then only 2 cores are presented to the OS. So you should * either disable hyperthreading as per the guide and use isolcpus=1 (as there are only 2 cores visible to the OS in this case you can/need reserve only 1 for realtime tasks) or * enable hyperthreading and use isolcpus=2,3 (that will reserve both hyperthreads of second core for realtime tasks) either bullet point should lead to improved latency figures. Robert _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
