On 03/03/2018 05:54 AM, Mick wrote:
UDP encapsulation as used for e.g. VPN does not suffer with the same problem because it does not use the same transmission quality control mechanism as TCP.
I think it's fair to say that it doesn't suffer at the protocol (TCP / UDP) level. There is nothing to prevent higher application layer retransmissions from compounding things.
I am not sure if block device I/O protocols suffer the same problem - I don't really know how the read/write SCSI commands are queued and processed between host and guest OS. What I have noticed is abstraction layers relating to partitioning schemes, e.g. good ol' primary Vs logical partitions, make a difference *only* when the partition is initially mounted, but not thereafter.
I've always operated under the assumption that there was additional logic ~> complexity, thus it must be slightly slower.
That being said, I've long held that the performance overhead is extremely likely negligible and can be ignored. At least unless you are trying to squeeze every bit of performance out of something. I.e. HPC or low power / low speed devices.
-- Grant. . . . unix || die
