Attached is a new script for testing network performance. Rather than measuring 
the transfer rate
to/from an Iperf server, this Perl script measures transmit and receive rates 
by transferring a file
from the computer under test to a mounted NFS system and back. The file on the 
destination is
deleted before the transfer is begun to avoid (as much as possible) any effects 
of caching.

For this test, I used my trusty server that is attached to the router by a 
100BaseTX wired
connection. Both wireless and wired connections were as free of other traffic 
as possible. I tested
3 different BCM chips as before. The results are stated in KB/s, where 1KB = 
1024 B. The first
number is for transmit, the second for receive. The file used for these tests 
is roughly 3 MB.

Wireless Rate    BCM4306 ver 2       BCM4318 ver 3        BCM4311
========================================================================

 6 Mbs           297.2 /  727.0      366.8 / 1798.2       370.9 / 1497.3
 9 Mbs           415.0 /  555.3      458.1 / 1821.9       461.1 / 1628.5
11 Mbs           436.4 /  673.6      470.7 / 1526.4       481.2 / 1411.9
18 Mbs           563.2 /  752.7      624.6 / 2006.0       566.5 / 1337.6
24 Mbs           595.8 /  718.9      681.7 / 1481.9       692.1 / 1688.2
36 Mbs           653.9 /  712.9      749.4 / 1504.2       751.0 / 1445.0
48 Mbs           681.2 /  716.6      518.9 / 1674.6       352.5 / 1509.7

The receive speeds are considerably higher than the results for transmit. I 
interpret this to mean
that the AP is sending as fast as it thinks is reliable, and the only effect of 
the Mbs rate is in
the transmission of the ACK's. In addition, there are fewer parameters that 
need to be set for the
receiver than for the transmitter. The jitter in the receive rate probably 
indicates the reliability
of these numbers. Performance of the early BCM4306 is worst with the 4318 and 
4311 roughly
comparable, although the 4318 is much better at the 48 Mbs rate. It even works 
with a 54 Mbs setting.

The patch posted today under the subject "[PATCH] bcm43xx: Change 
initialization for 2050 radios"
improves these numbers by a factor of two or more, particularly for the 4306.

Larry

Attachment: file_test.pl
Description: Perl program

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