On Wed, 16 Jul 2008, Pavel Roskin wrote:
> On Wed, 2008-07-16 at 15:41 -0400, Clem Taylor wrote:
>> /proc/net/madwifi/ath0/rate_info (minstrel) shows many attempts but a
>> very small (or zero) number of successes.
>
> I believe it's all caused by HAL.  That's the reason we haven't made any
> releases with the HAL we have in trunk.
>
> You may want to test "sample" instead of "minstrel" to see if it makes
> any difference.

Why would sample work better than minstrel?
The report from the rate_info file shows very few successes - in other 
words, the packets are not getting through. If the packets are not getting 
through, changing the rate_algorithm won't help.

Given that he reports using minstrel with the trunk r3773, it is probable 
he was using minstrel with 0.9.4. So - why did it slow down on changing 
from 0.9.4 to trunk r3773?
The rate algorithm has not changed significantly.

To verify the rate algorithm is your problem, set both ends to fixed rate 
(1Mb/sec) and see if that helps.
then set both ends to 2Mb/sec, and see if that helps.

================================================
I have noticed in one of the builds I did here that the rate table used by 
minstrel was being constantly reset to zero. All entries in the 
/proc/net/madwifi/ath0/rate_info tended to zero within seconds of data 
transfer. This incorrect behaviour happened because on each state 
transition, the ath_rate_ctl_reset function was being called.

I found a performance improvement by (in ath_rate_newstate)
removing the call to
      ieee80211_iterate_nodes(&ic->ic_sta, ath_rate_cb, NULL);

Derek.
  -- 
Derek Smithies Ph.D.
IndraNet Technologies Ltd.
Email: derek <at> indranet.co.nz
ph +64 3 365 6485
Web: http://www.indranet-technologies.com/

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