HMS CPU Usage

odd-numbered hyper-threads are used to data-plane tasks

 

even-numbered hyper-trheads are used to control-plane tasks

 

Other way round - even vCPUs are data-plane, odd vCPUs are control-plane

 

1) First question -> Are Management tasks equivalent to control-tasks? (i.e. TMSH, SNMP, REST are processed in even-numbered threads?)

 

Yes. Those processes run on the odd-numbered cores.

 

2) Second question -> In case of just a single CPU is used (eq to old behaviour), Does HMS share CPU resources with TMM? Which CPU number is used?

 

A single non-hyperthreaded core will behave in the old way, with control-plane and data-plane processes sharing CPU resource.

 

A single hyperthreaded CPU core will be split, and tmm (data-plane) runs on core0 and control-plane processes run on core1.

 

There is an option in VCMP to assign a single hyperthread core to a guest, but this does have some limitations.

 

Our development team estimates that for typical LTM workloads, a single CPU core using HT-Split can safely reach about 120% of the performance of the single (non-hyperthreaded) CPU core.

 

Once core0 reaches 80% of the single non-hyperthreaded CPU core performance, core1 will be limited to 20%. Core0 performance can then approach 100% (with the two hyperthreads reaching about 120% utilization).