[Beowulf] Re: typical latencies for gigabit ethernet

Dave Love d.love at liverpool.ac.uk
Tue Jun 30 06:07:59 PDT 2009


Patrick Geoffray <patrick at myri.com> writes:

> Instead of rx-usecs being the time between interrupts, it is sometimes 
> implemented as the delay between the the first packet and the following 
> interrupt, which is obviously wrong.

Ah.  Is that likely to be in the driver, where it might be fixed, or the
NIC firmware?

> rx-frames may generate an interrupt storm if you receive a stream of 
> small packets. You may want to measure how many interrupts per second 
> are produced in this case, compared to using rx-usecs.

Yes, but I'm not sure how useful that is since the rx-usecs adjustment
doesn't seem sensible in this case.  Also I'm not actually interested in
tg3 for production use, so maybe someone who is would like to try.



More information about the Beowulf mailing list