Il 18/10/2012 09:29, Juan Quintela ha scritto: > v3: > > This is work in progress on top of the previous migration series just sent. > > - Introduces a thread for migration instead of using a timer and callback > - remove the writting to the fd from the iothread lock > - make the writes synchronous > - Introduce a new pending method that returns how many bytes are pending for > one save live section > - last patch just shows printfs to see where the time is being spent > on the migration complete phase. > (yes it pollutes all uses of stop on the monitor) > > So far I have found that we spent a lot of time on bdrv_flush_all() It > can take from 1ms to 600ms (yes, it is not a typo). That dwarfs the > migration default downtime time (30ms). > > Stop all vcpus: > > - it works now (after the changes on qemu_cpu_is_vcpu on the previous > series) caveat is that the time that brdv_flush_all() takes is > "unpredictable". Any silver bullets?
You could reuse the "block" live migration item. In block_save_pending, start a bdrv_aio_flush() on all block devices that have already completed the previous one. But that's not a regression in the migration thread, isn't it? Paolo
