Re: [PATCH 0/5] optimize the downtime for vfio migration

[Longpeng (Mike, Cloud Infrastructure Service Product Dept.)]

Hi maintainers,

Ping...

在 2021/8/25 15:56, Longpeng(Mike) 写道:
> In vfio migration resume phase, the cost would increase if the
> vfio device has more unmasked vectors. We try to optimize it in
> this series.
> 
> Patch 1 & 2 are simple code cleanups.
> Patch 3 defers to set irqs to vfio core.
> Patch 4 & 5 defer to commit the route to KVM core. 
> 
> The test VM has 128 vcpus and 8 VF (with 65 vectors enabled),
> we mesure the cost of the vfio_msix_enable for each one, and
> we can see the total cost can be significantly reduced.
> 
>         Origin         Apply Patch 3     Apply Patch 3/4/5   
> 1st     8              4                 2
> 2nd     15             11                2
> 3rd     22             18                2
> 4th     24             25                3
> 5th     36             33                2
> 6th     44             40                3
> 7th     51             47                3
> 8th     58             54                4
> Total   258ms          232ms             21ms
> 
> 
> Longpeng (Mike) (5):
>   vfio: use helper to simplfy the failure path in vfio_msi_enable
>   msix: simplfy the conditional in msix_set/unset_vector_notifiers
>   vfio: defer to enable msix in migration resume phase
>   kvm: irqchip: support defer to commit the route
>   vfio: defer to commit kvm route in migraiton resume phase
> 
>  accel/kvm/kvm-all.c    | 10 +++--
>  accel/stubs/kvm-stub.c |  3 +-
>  hw/misc/ivshmem.c      |  2 +-
>  hw/pci/msix.c          |  7 ++--
>  hw/vfio/pci.c          | 99 
> ++++++++++++++++++++++++++++++++++++++------------
>  hw/vfio/pci.h          |  1 +
>  hw/virtio/virtio-pci.c |  2 +-
>  include/sysemu/kvm.h   |  4 +-
>  target/i386/kvm/kvm.c  |  2 +-
>  9 files changed, 95 insertions(+), 35 deletions(-)
>