Frank Kardel <[email protected]> writes: >> Have you done dd bs=1m from the dom0 raw disk, the dom0 backing file, >> and the domU ('raw disk')? I used to see X, 0.9X, and (0.9)^2 X, ish, >> on somewhat old Xen and older NetBSD. > Before this load test I reach 990Mb/s in DOMU instead of 1100Mb/s on DOM0.
That sounds good and slightly better than my 0.9^2, but close. >> I also wonder if there is some sort of fsync in the domU leading to >> virtual FUA leading to fsync in the dom0 going on. > > Could be, but in that case I would still expect a reasonably data > stream to the disks then and not several seconds of inactivity. Overall this smells like a locking bug. You might try LOCKDEBUG in the dom0. You might also try 1 vcpu in the domU.
