Announcement

Collapse
No announcement yet.

KVM SR-IOV question: is there a maximum amount of interrupt vectors?

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • KVM SR-IOV question: is there a maximum amount of interrupt vectors?

    Hi,

    I didn't have any luck in the kvm mailing list, so I thought to myself, what other forums know linux in-depth (or know who to ask , Phoronix of course, so here goes:

    Sorry to bother you all.

    In ESXI 6.0 you can have 4096 interrupt vectors if you have 32 CPU's, so 128 interrupt vectors per CPU.

    How does KVM handle this (I haven't bought the server hardware yet)?

    Basically I want to have 64 guests on a x86 KVM host, all of which will need 4 x SR-IOV VF's. The host will have two X540-T2. So basically I will have 256 interrupt vectors just for networking. I
    don't actually need 10GbE, only 1GbE but I do need the 64 VF's on the X540, the 64 guests will not use more than 1Gbps combined, I assume I will still have the 64 VF's on the X540 at 1Gbps (I did see a post somewhere asking about bandwidth errors in the linux logs when enabling "sriov_numvfs")?

    I also read about this KVM limitation: the maximum number of Virtual Functions that can be mapped to a single VM is 7. KVM will not allow a VM to start with more than 7 VFs. I think I am OK with 4.

    Also is there a difference in the interrupt vectors supported on Intel and AMD.

    Thanks for looking.

    Richard
Working...
X