Enable automatic NUMA balancing on lizard
After reading chapter 8 on
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html-single/Virtualization_Tuning_and_Optimization_Guide/index.html#sect-Virtualization_Tuning_Optimization_Guide-NUMA-Auto_NUMA_Balancing
and other Red Hat performance tuning doc, I came to the conclusion that
we should enable automatic NUMA balancing on lizard (echo 1 > /proc/sys/kernel/numa_balancing
, i.e.
sysctl::value { 'kernel.numa_balancing': value => 1 }
).
It is supposed to give us better performance, and the other options are not practical:
- manual NUMA tuning: quite some initial + maintenance work, let’s avoid this if we can
- numad: the package is in Stretch but not in Jessie, and according to Red Hat it’s not really more efficient than automatic NUMA balancing
To be able to evaluate how well this works, we can:
- benchmark
- use
numastat -c qemu-system-x86_64
, that gives per-command information, so we can easily check what CPUs our kvm processes are using; see 8.3 on https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html-single/Virtualization_Tuning_and_Optimization_Guide/index.html)
Related issues
- Related to #15832 (closed)
-
Blocked by #11178 (closed) -
Blocked by #11817 (closed)
Original created by @intrigeri on 11179 (Redmine)