On Sun, Dec 05, 2021 at 01:32:17PM -0500, Waiman Long wrote: > Cpuset v1 uses the sched_load_balance control file to determine if load > balancing should be enabled. Cpuset v2 gets rid of sched_load_balance > as its use may require disabling load balancing at cgroup root. > > For workloads that require very low latency like DPDK, the latency > jitters caused by periodic load balancing may exceed the desired > latency limit. > > When cpuset v2 is in use, the only way to avoid this latency cost is to > use the "isolcpus=" kernel boot option to isolate a set of CPUs. After > the kernel boot, however, there is no way to add or remove CPUs from > this isolated set. For workloads that are more dynamic in nature, that > means users have to provision enough CPUs for the worst case situation > resulting in excess idle CPUs. > > To address this issue for cpuset v2, a new cpuset.cpus.partition type > "isolated" is added which allows the creation of a cpuset partition > without load balancing. This will allow system administrators to > dynamically adjust the size of isolated partition to the current need > of the workload without rebooting the system. you can, ofcourse, create lots of 1 cpu partitions, which is effectively what you're doing, except there was a problem with that which you also forgot to mention.
