if_ral regression

Sepherosa Ziehau sepherosa at gmail.com
Wed Jan 2 05:28:32 PST 2008


On Jan 2, 2008 10:38 AM, Weongyo Jeong <weongyo.jeong at gmail.com> wrote:
>
> > Even with these in place in dfly, I still have strange TX performance
> > regression in sta mode (drop from 20Mb/s to 3Mb/s under very well
> > condition) on certain hardwares after 20sec~30sec TCP_STREAM netperf
> > testing; didn't have enough time to dig, however, all of the tested
> > hardwares stayed connected during testing (I usually run netperf
> > stream test for 12 hours or more).
>
> I also saw some regression in TX performance during porting malo(4).

Have you tried to turn bgscan off completely?  My problem seems to be
hardware (I suspect rf) related.  The TX performance regression does
not happen with UDP stream which only uses 802.11 ack, i.e. hardware
seems to have touble to switch between data RX and data TX at high
freq.

> Problems were fixed after removing following lines in *_start:
>
>                         /*
>                          * Cancel any background scan.
>                          */
>                         if (ic->ic_flags & IEEE80211_F_SCAN)
>                                 ieee80211_cancel_scan(ic);
>
> and (optionally)
>
>                 if (m->m_flags & M_TXCB)
>                         ...
>                         ieee80211_process_callback(ni, m, 0);   /* XXX status?
>                         ...

I don't think you can remove TXCB processing in drivers :)

Best Regards,
sephe

-- 
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