Date: Tue, 27 Mar 2018 19:18:16 +0200
From: Stanislaw Gruszka <sgruszka@redhat.com>
To: Mathias Kresin <dev@kresin.me>
Cc: Daniel Golle <daniel@makrotopia.org>,
        Enrico Mioso <mrkiko.rs@gmail.com>,
        Tom Psyborg <pozega.tomislav@gmail.com>,
        linux-wireless <linux-wireless@vger.kernel.org>,
        Johannes Berg <johannes.berg@intel.com>,
        Arnd Bergmann <arnd@arndb.de>, John Crispin <john@phrozen.org>,
        Felix Fietkau <nbd@nbd.name>,
        Jamie Stuart <jamie@onebillion.org>
Subject: Re: ieee80211 phy0: rt2x00queue_write_tx_frame: Error - Dropping
 frame due to full tx queue...?
Message-ID: <20180327171815.GA31338@redhat.com> (sfid-20180327_191911_313541_D6AD4008)
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On Tue, Mar 27, 2018 at 09:46:36AM +0200, Mathias Kresin wrote:
> > Could you test just RX AMPDU patches, i.e.
> > 
> > rt2800_change_rx_ampdu_factor.patch
> > rt2800_change_rx_ampdu_density.patch
> > 
> > I have somewhat positive results on RX performance on some devices
> > with those. Perhaps you could confirm that :-)
> 
> This time I've done the test with HT20 only, to not annoy my neighbours.
> 
> The test setup is the following:
> 
> ath9k (STA) <=> (AP) o2 Box 6431 (RJ45) <=> desktop
> 
> With the patches applied the bandwidth is somewhat around 10 MBit/sec lower.
> Even if I was able to reliable reproduce it, I'm not sure if it is within
> the measuring tolerance.

Ok. I think when BBP/RF is correctly programmed patches will downgrade
performance. For not well optimized devices patches might
improve things , but this is not preferred solution. For 30+ client
scenario I suggest to just disable HT (11n) in OpenWRT config.

Additionally since those errors do not happen frequently perhaps there
is possibility to create watchdog and reset the device when problems
start to happen.

FWIW: I'm running wt3020 (mt7620 device) as my home router for 3 weeks now
and do not see any errors (I have 4 client devices). Performance measured
by iperf is not good though - about 40 Mbit/s .

Regards
Stanislaw