Saturates 100 Mb/s channel (Was: Re: kernel performance degradation.)

Ove Ewerlid (
Sat, 02 May 1998 23:46:59 +0000

C. Scott Ananian wrote:

> Any volunteers? Any previous benchmark results to report?

Just a little note that 2.1.99, is the first kernel that (I) have been able to
saturate a
100 Mb/s ethernet using this method:

4 machines attached to a 3com superstack 3300.

Machine A: PPro-200 Mhz; 3c905 fullduplex

Machine B/C/D: P133/P166/PPro200 3c59x half/full duplex

B: rsh A "cat /dev/zero" > /dev/null
C: rsh A "cat /dev/zero" > /dev/null
D: rsh A "cat /dev/zero" > /dev/null

Surfing in on the Superstack 3300 to check the port of machine A reveals
that 100% of the bandwidth is used. B/C/D is getting roughly 3.8-4.0 Mbytes/s.

It is possible to login to machine A and run a matlab benchmark.
There is still 30 % CPU left for that.

However, there sometimes seems to be short (2-3 s) of loss of network
from host A.

Before 2.1.99 this setup would be hopelessly jerky and A would not be able to
come higher
then 6-7 Mbytes/s. Your mileage may vary!


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