On 12/31/06, Daniel Drake <[EMAIL PROTECTED]> wrote:
> Jon Smirl wrote:
> > I just spent a while with Windows booted on the same hardware. With no
> > trouble at all I am able to achieve 19Mb/sec of useful file copy
> > throughput.
> Matching the windows driver behaviour is hard, since we don't have the
> source. A much more worthwhile test would be using the Linux vendor
> driver, again as I wrote in an earlier mail.
> > Allocating memory instead of using a circular buffer may be the source
> > of dropped packets.
> I strongly doubt that, but it would certainly be a worthwhile change
> anyway so feel free to try and prove me wrong by patching it in :)
I checked against WIndows mainly for the purpose of eliminating all of
the other variables. For example checking against Window let me figure
out that it was my Nokia 770 kismet dropping some of the packets, not
This is the best source for the vendor driver, right?
After playing with it some last night I believe there are two problems.
1) Something catastrophic happens during my copies and causes the
session to be dropped. Short preambles aggravate this problem. This
problem is infrequent, but fatal. Doesn't happen on Windows with same
hardware, session never drops.
2) If I try my 250MB copy at 54M every once in a while I won't hit the
problem in #1 and this allows me to measure the transfer rate.
Setting all rates from 18M to 54M result in copy times that are almost
exactly the same. This makes me wonder if the higher rates are really
getting set. Or if they are being set, are some other parts of the low
level protocol still working at the lower speeds. This is probably a
better explanation than dropped packets; dropped packets would have
more statistically variability in the transfer times for the copies.
Doesn't happen on Windows with same hardware, setting different rates
results in different copy times.
I wish I had better test equipment for decoding the radio signals to
see what is really going on. Better equipment would solve #2
I'll check out the vendor driver next.
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