Hamachi on alpha bad packets
Thu Mar 18 22:55:46 1999
I'd appreciate a sanity check from other hamachi users. On alpha,
either kernel 2.2.1 or 2.2.3, I get lots of Tcp InErrs when running
bandwidth trials (ttcp). They don't happen over a different ethernet
interface in the machine. Would you look at the InErrs setting by:
% egrep '^Tcp' /proc/net/snmp
Tcp: [...] InErrs OutRsts
Tcp: 0 0 0 0 4 0 0 0 0 166421 84174 0 149 0
and see if that next-to-last number goes away from zero on your
machines as it does on mine?
I generate the badness by running ttcp as such:
% nttcp2 -l 16384 -n 32768 -b 60000 -r
while the other side sends packets. Only the receiver sees errors.
I'm using a Becker stock-0.07 hamachi driver, with no checksumming or
modified parameters, on an alpha miata 433. The machines are directly
connected. Some combinations of length/buffersize seem more error-
prone than others. Either machine, acting as receiver, generates
errors. Swapping the fibre didn't help.
Instrumenting the kernel shows the errors are mostly due to PAWS-based
discards when receiving a time stamp earlier than one which had
previously been sent out. A couple of plain bad checksums happen every
so often too. These errors don't keep the transfer from completing,
but probably slow it down.
Pete Wyckoff | firstname.lastname@example.org
Sandia National Labs | 925 294 3503 (voice)
MS 9011, P.O. Box 969 | 925 294 1225 (fax)
Livermore, CA 94551 |
| To unsubscribe, send mail to Majordomo@cesdis.gsfc.nasa.gov, and within the
| body of the mail, include only the text:
| unsubscribe this-list-name email@example.com
| You will be unsubscribed as speedily as possible.