ff5c52a379
block_mig_state.total_time is currently the sum of the read request latencies. This is not very accurate because block migration uses aio and so several requests can be submitted at once. Bandwidth should be computed with wall-clock time, not by adding the latencies. In this case, "total_time" has a higher value than it should, and so the computed bandwidth is lower than it is in reality. This means that migration can take longer than it needs to. However, we don't want to use pure wall-clock time here. We are computing bandwidth in the asynchronous phase, where the migration repeatedly wakes up and sends some aio requests. The computed bandwidth will be used for synchronous transfer. Signed-off-by: Avishay Traeger <avishay@il.ibm.com> Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Read the documentation in qemu-doc.html. Fabrice Bellard.