Hi Shirley, I think you are right, isolcpus is for userspace threads. ... "Use the isolcpus parameter on the kernel command line to isolate certain cores from user-space tasks." ... See: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/performance_tuning_guide/sect-red_hat_enterprise_linux-performance_tuning_guide-cpu-configuration_suggestions So if there is no way to configure JVM to use specified kernel cores (and I am afraid there is no such way), I am not sure how this can be solved.
Regards, Rami Rosen On Wed, Jan 30, 2019 at 9:05 AM Shirley Avishour <shir...@imvisiontech.com> wrote: > Hi Rami, > > This is the printout for cat /proc/cmdline > BOOT_IMAGE=/boot/vmlinuz-4.15.0-43-generic > root=UUID=6f1a210b-a30f-456d-bf16-bbb210da5666 ro default_hugepagesz=2M > hugepagesz=2M hugepages=4096 isolcpus=1-5 nohz_full=1-5 rcu_nocbs=1-5 > > The requires cpus are in fact isolated but jvm generate some kernel > threads as well and I'm afraid that these kernel space threads eventually > use all cores. isolcpus is not applies on kernel space threads. > > Shirley. > > > > On Wed, Jan 30, 2019 at 8:57 AM Rami Rosen <ramir...@gmail.com> wrote: > >> Hi Shirley, >> >Running java based applications on the same server with a dpdk based >> application has an impact on the dpdk performance. >> Probably since the JVM generates kernel based processes. I >> >> This is true, but as far as I know, using isolcpus should prevent these >> processes to run on the isolated cores. >> >> Just to be on the safe side: did you make sure with cat /proc/cmdline on >> the kernel you are actually running indeed >> has the "isolcpus=1-5" you added in grub ? sometimes, especially in >> multi OS hosts, adding entries in /etc/default/grub and running >> grub2-mkconfig >> is not enough, if you boot from a different partition. >> >> Regards, >> Rami Rosen >> >> >> -- regards, Rami Rosen
