On Fri, Apr 08, 2022 at 12:08:02PM +0100, Julien Grall wrote: > Hi, > > On 08/04/2022 12:01, Roger Pau Monné wrote: > > > > I could add a suitable dom0_max_vcpus parameter to osstest. XenServer > > > > uses 16 for example. > > > > > > I'm afraid a fixed number won't do, the more that iirc there are > > > systems with just a few cores in the pool (and you don't want to > > > over-commit by default). > > > > But this won't over commit, it would just assign dom0 16 vCPUs at > > most, if the system has less than 16 vCPUs that's what would be > > assigned to dom0. > > AFAICT, this is not the case on Arm. If you ask 16 vCPUs, then you will get > that number even if there are 8 pCPUs. > > In fact, the documentation of dom0_max_vcpus suggests that the numbers of > vCPUs can be more than the number of pCPUs.
It was my understanding that you could only achieve that by using the min-max nomenclature, so in order to force 16 vCPUs always you would have to use: dom0_max_vcpus=16-16 Otherwise the usage of '_max_' in the option name is pointless, and it should instead be dom0_vcpus. Anyway, I could use: dom0_max_vcpus=1-16 Which is unambiguous and should get us 1 vCPU at least, or 16vCPUs at most. But given Jans suggestion we might want to go for something more complex? Thanks, Roger.
