Comment 19 for bug 1100843

Quoting Chris Cormier (<email address hidden>):
> @serge-hallyn
> I'm using Netapp filer in c-mode for NFS storage, mount options are: (rw,nosuid,nodev,noatime,hard,nfsvers=3,tcp,intr,rsize=32768,wsize=32768,addr=x.x.x.x).
>
> However, I can reproduce this on a a host with or without NFS, using
> local disk, qcow2, or raw images and the OP was using FC SAN.
>
> I've tried to reproduce your success by buiding a new VM the latest
> preciese 12.04.02 with updates, but i have been unsuccessful. It happens
> immediately after the restore 100% of the time.
>
> The quickest test i've found is this, it helps aid in your reproduction as it's an immediate indication.
> -Get/Compile lmbench
> -build it
> -run
> # touch tmpfile
> # for i in null read write open ; do sleep 1; ./lat_syscall -N 1 $i tmpfile; done
> - the latencies for read/write generally increase up to 2x, and the open/close by about 30% post restore.

i did this and got the attached results (.1 before save, .2 after
restoer). This is with precise guest on precise host over nfs (from
a raring nfs server).

results.1 (before save)
Simple syscall: 0.1468 microseconds
Simple read: 0.3555 microseconds
Simple write: 0.2785 microseconds
Simple open/close: 3.3682 microseconds
serge@p1:~/lmbench3$ ./sergetest
Simple syscall: 0.1466 microseconds
Simple read: 0.3412 microseconds
Simple write: 0.2813 microseconds
Simple open/close: 3.3175 microseconds
serge@p1:~/lmbench3$ ./sergetest
Simple syscall: 0.1582 microseconds
Simple read: 0.3403 microseconds
Simple write: 0.2871 microseconds
Simple open/close: 2.7587 microseconds
serge@p1:~/lmbench3$ ./sergetest
Simple syscall: 0.1453 microseconds
Simple read: 0.3371 microseconds
Simple write: 0.2790 microseconds
Simple open/close: 3.3391 microseconds

results.2 (after restore)
Simple syscall: 0.1457 microseconds
Simple read: 0.3370 microseconds
Simple write: 0.2832 microseconds
Simple open/close: 3.1675 microseconds
Simple syscall: 0.1470 microseconds
Simple read: 0.3436 microseconds
Simple write: 0.2812 microseconds
Simple open/close: 2.8002 microseconds
Simple syscall: 0.1452 microseconds
Simple read: 0.3428 microseconds
Simple write: 0.2817 microseconds
Simple open/close: 2.7974 microseconds
Simple syscall: 0.1456 microseconds
Simple read: 0.3722 microseconds
Simple write: 0.2798 microseconds
Simple open/close: 2.7494 microseconds
Simple syscall: 0.1470 microseconds
Simple read: 0.3362 microseconds
Simple write: 0.2830 microseconds
Simple open/close: 2.7640 microsecond