Re: [Qemu-devel] virtio-serial-pci very expensive during live migration

[Paolo Bonzini]

Il 06/05/2014 22:01, Chris Friesen ha scritto:
> It seems like the main problem is that we loop over all the queues,
> calling virtio_pci_set_host_notifier_internal() on each of them.  That
> in turn calls memory_region_add_eventfd(), which calls
> memory_region_transaction_commit(), which scans over all the address
> spaces, which seems to take the vast majority of the time.

Yes, you can wrap the entire loop with memory_region_transaction_begin 
and memory_region_transaction_commit.  Can you try that?

Paolo