Problems with LinkSys 10/100 cards

Brian Denheyer
Fri Feb 5 15:59:29 1999

>>>>> "Robert" == Robert G Brown <> writes:

    Robert> Yes, note well that measured transfer rates depend
    Robert> strongly on CPU speed and packet size for packets less
    Robert> than around 1K in size.  There is a graph, and set of
    Robert> instructions for measuring performance with netperf, on
    Robert> (the graph is even for a tulip
    Robert> card, although not a linksys).  Measured throughput will
    Robert> also depend strongly on the CPU load on the receiver (and
    Robert> other things, but these three are the primary
    Robert> determinants).

I looked at the graph and let me tell you I am getting nothing like
that performance.  Now supposedly the hacks which Steve posted should
help, but since I can't get 0.90k to behave reliably, I haven't rolled
those back in.  I am also trying to figure out what they do, and so
far the hacks do NOT make sense in relation to the datasheet.  Pretty
normal for hardware...  I am running these tests with very low CPU
load, i.e., nothing else of significance is going on.

I'm in the process now of trying to track down the differences between
the PNIC and the 21143 and see if there is something obvious going on.
But as of right now both netperf and netpipe break the drivers quite
repeatably.  The problem does seem worse in "one direction".

Of course the PNIC datasheet is *1994*, so I think I'm pretty much not
going to be able to figure out what's going on.


It'd be a heck of a lot easier to go out and buy two new network