New bhyve user

[ghislain]

>> In Xen there is a maxvcpus which limit the number of CPUs but they could baloon down if not busy so that other clients who are busy can use the CPUs.  In bhyve (at least in vm-bhyve) there is only a cpus line in the config.  >Is this a minimum, maximum or is it a hard limit?
> This is the number of virtual cpus that the guest will see. Remember that as far as the host is concerned, the guests are processes that are using resources, just like any other program. A guest that is not doing much will not being using much cpu time on the host, and the host will happily run other guests (or system processes) on the same physical cpus.

if i understood the other comments on the list on previous thread there is not any mecanism to prioritize guest from 
other guest and share fairly between them when they share a cpu core.

  The freebsd kernel will treat all process equaly. If i am correct the only way to have a fair distribution is to bind 
guest to a cpu but then you loose the sharing possibility if one is idle. If you let just everyone have the whole cpu 
access then there is no rule about which guest will have the cpu time as the kernel do not know how to partition the cpu 
time per guest, only per process.

  So if one guest launch a lot of cpu hungry thread it could "starve" the others guests with less thread usgin cpu time.

Correct me if i read that wrong :)

Ghislain.