On 12.11.2023 21:28, Jimmy Lee wrote: > Hello Xen experts, I am trying to set dom0_max_vcpus to a number that is > larger than the number of pcpus. For example, I have a 4-CPU machine but I > want applications in dom0 to have an illusion that they are running on a > 64-cpu machine. However, it seems that dom0 will always recognize the > number of pcpus. I can see the vcpus in the output of "xl vcpu-list" but > most of them are not online. How can I achieve my goal? Thanks!
Even if I was to assume the Dom0 kernel is Linux, it would still remain unclear what Linux version you use. Generally with recent Linux kernels this has been working for me (albeit I didn't try in a while, after putting together what has become e25a8d959992 ["x86/Xen: streamline (and fix) PV CPU enumeration"]). If despite having this in your Linux you still don't see this working, you will want to supply applicable logs. As an aside - 64 vCPU-s on a 4-pCPU system looks excessive to me. Jan > [root@ip-10-0-131-61 cpu3]# xl vcpu-list >> Name ID VCPU CPU State Time(s) >> Affinity (Hard / Soft) >> Domain-0 0 0 0 r-- 15.9 all / >> all >> Domain-0 0 1 3 -b- 11.9 all / >> all >> Domain-0 0 2 1 -b- 11.2 all / >> all >> Domain-0 0 3 2 -b- 12.4 all / >> all >> Domain-0 0 4 - --p 0.0 all / >> all >> Domain-0 0 5 - --p 0.0 all / >> all >> Domain-0 0 6 - --p 0.0 all / >> all >> Domain-0 0 7 - --p 0.0 all / >> all >> Domain-0 0 8 - --p 0.0 all / >> all >> .... >> > > [root@ip-10-0-131-61 cpu3]# lscpu > Architecture: x86_64 > CPU op-mode(s): 32-bit, 64-bit > Byte Order: Little Endian > CPU(s): 4 > On-line CPU(s) list: 0-3 > Thread(s) per core: 4 > Core(s) per socket: 1 > Socket(s): 1 > NUMA node(s): 1 > ... > > [root@ip-10-0-131-61 cpu3]# xl info > ... > xen_commandline : placeholder dom0_mem=3%,min:2G,max:4G > com1=115200,8n1 console=com1,tty,vga dom0_max_vcpus=64 spec-ctrl=no > sched=credit vcpu_migration_delay=1000 allowsuperpage ioapic_ack=new > ... >
