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Subject: Re: ax200 very poor performance in stock 5.7.0 and 53.c3 firmware.
To:     Tim Higgins <tim@timhiggins.com>
References: <c2898228-836e-549b-85ee-8c2d24051912@candelatech.com>
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 <8f1f9938-2fa6-38ca-b9e8-c792078ee3c1@candelatech.com>
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From:   Ben Greear <greearb@candelatech.com>
Message-ID: <d54f2506-36db-3888-9460-a1170d892104@candelatech.com>
Date:   Tue, 9 Jun 2020 08:24:10 -0700
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On 06/04/2020 07:38 AM, Ben Greear wrote:
>
>
> On 06/04/2020 04:35 AM, Tim Higgins wrote:
>>
>>
>>> On Jun 3, 2020, at 11:54 PM, Ben Greear <greearb@candelatech.com> wrote:
>>>
>>> I'm testing an un-modified kernel for a change, and latest firmware that I could find,
>>> but ax200 is still sucking.
>>>
>>> UDP upload of single ax200 station gets about 1Mbps, and station disconnects
>>> very often.  TCP download gets about 400Mbps on each of two radios.  UDP download stalls
>>> often and averages around 1Mbps throughput.  TCP upload also stalls out.
>>>
>>> Previous testing on other kernels has shown problems with other firmware as well.
>>>
>>> I'm requesting 500Mbps UDP speeds.    Requesting only 100Mbps does not help (tested with DL direction only).
>>>
>>> [root@ct523c-0b29 ~]# ethtool -i wlan2
>>> driver: iwlwifi
>>> version: 5.7.0
>>> firmware-version: 53.c31ac674.0 cc-a0-53.ucode
>>> expansion-rom-version:
>>> bus-info: 0000:12:00.0
>>> supports-statistics: yes
>>> supports-test: no
>>> supports-eeprom-access: no
>>> supports-register-dump: no
>>> supports-priv-flags: no
>>>
>>>
>>> Is there any way to disable OFDMA or /ax on the ax200 in case that helps somehow?
>>>
>>> Thanks,
>>> Ben
>> Hi Ben,
>> Try running with no encryption. I know that is not a solution. But it could point to a cause. I've seen disabling encryption make a big difference.
>
> I set to open auth (was using wpa3 PSK previously), and started TCP upload on two stations.  One is doing around 80Mbps, the other seems to have crashed the firmware
> and will not recover.

To follow up on this...

I tried the backports-iwlwifi project, and that driver is significantly more stable.  But, you cannot use any other
mac80211 driver (ie, ath10k) with the backport-iwlwifi modules loaded since the ath10k would have been compiled against a different
mac80211 and then ath10k crashes on startup.

So, I ported the backports-iwlwifi driver into my 5.4 kernel, and enough of the mac80211 changes as well so it could
compile.

This is working OK-ish, though FW still crashes and wlans don't always restart properly after crash.

Looks like I can work around this last part by bouncing things in user-space after detecting a crash...

Thanks,
Ben

-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com