AX86U High CPU Usage and Packet Loss

[NotJackieChan]

Hi guys

My setup is an AX86U router - connected to a powerline and to an RTN66U in access point mode in a different room. The RTN66U also performs as a network switch to several devices.
I have been suffering from spikes of packet loss when gaming. I notice that when this happens the CPU usage of the router spikes and there is a flurry of the following entry in the system log:

Mar 24 23:01:47 kernel: CONSOLE: 259091.499 ppr_get_vht_mcs: Failed ppr_t:0046a1f0 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f4c
Mar 24 23:01:47 kernel: CONSOLE: 259091.569 ppr_get_vht_mcs: Failed ppr_t:0046a1f0 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f3c
Mar 24 23:01:47 kernel: CONSOLE: 259091.581 ppr_get_vht_mcs: Failed ppr_t:0046a1f0 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f4c
Mar 24 23:01:54 kernel: CONSOLE: 259098.745 ppr_get_vht_mcs: Failed ppr_t:0046a1f0 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f4c
Mar 24 23:01:54 kernel: CONSOLE: 259098.817 ppr_get_vht_mcs: Failed ppr_t:0046a1f0 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f3c
Mar 24 23:01:54 kernel: CONSOLE: 259098.888 ppr_get_vht_mcs: Failed ppr_t:0046a1f0 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f4c
Mar 24 23:01:56 kernel: CONSOLE: 259100.750 ppr_get_vht_mcs: Failed ppr_t:0046a1f0 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f3c
Mar 24 23:01:56 kernel: CONSOLE: 259100.752 ppr_get_vht_mcs: Failed ppr_t:0046a1f0 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f4c
Mar 24 23:01:58 kernel: CONSOLE: 259102.747 ppr_get_vht_mcs: Failed ppr_t:0046a1f0 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f4c
Mar 24 23:02:08 kernel: CONSOLE: 259112.582 ppr_get_vht_mcs: Failed ppr_t:0046a1f0 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f3c
Mar 24 23:02:08 kernel: CONSOLE: 259112.674 ppr_get_vht_mcs: Failed ppr_t:0046a1f0 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f3c
Mar 24 23:02:08 kernel: CONSOLE: 259112.761 ppr_get_vht_mcs: Failed ppr_t:0046a1f0 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f3c
Mar 24 23:02:08 kernel: CONSOLE: 259112.852 ppr_get_vht_mcs: Failed ppr_t:0046a1f0 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f4c
Mar 24 23:02:08 kernel: CONSOLE: 259112.853 ppr_get_vht_mcs: Failed ppr_t:0046a1f0 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f4c
Mar 24 23:02:10 kernel: CONSOLE: 259114.701 ppr_get_vht_mcs: Failed ppr_t:0046a1f0 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f3c
Mar 24 23:02:10 kernel: CONSOLE: 259114.755 ppr_get_vht_mcs: Failed ppr_t:0046a1f0 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f4c
Mar 24 23:02:10 kernel: CONSOLE: 259114.761 ppr_get_vht_mcs: Failed ppr_t:0046a1f0 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f4c

I have tried clean installing both the latest Merlin and Asus firmware to no avail.
I have tried disconnecting an unmanaged network switch to which several low bandwidth items are connected.
I have tried both with AI protection and QoS settings both on and off.

Unfortunately nothing has worked. I still get occasional CPU spikes to 50% plus on core 1 and my ping in games spike heavily.

I will take any suggestions at this point to be honest. I've been a little disappointed with the AX86U considering how fantastic my RTN66U and even the ISP provided BT Home Hub was for me prior to purchasing this.

Thank you in advance

 

[kibosh]

I personally have found the 384 series of firmware to be more reliable on the AX86U. I keep trying the new versions but I end up with some weird wireless issues and revert back to 384.9318.

 

[bbunge]

Try the Merlin 386.2 beta 2. I was off Merlin for a while but decided to give the new beta a go. Works well for me.

 

[sfx2000]

Mar 24 23:01:47 kernel: CONSOLE: 259091.499 ppr_get_vht_mcs: Failed ppr_t:0046a1f0 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f4c

Looks like a client WiFi adapter issue, IMHO..

NSS:1 -- single stream

 

[hprogramming]

Hi NotJackieChan,

Have you manged to find the root cause and fix it?

Thanks.

 

[wasko]

Just wondering if you ever managed to resolve this? I seem to be having a similar issue:

Sep 21 15:48:23 kernel: CONSOLE: 309092.462 ppr_get_vht_mcs: Failed ppr_t:00465314 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f4c
Sep 21 15:48:25 kernel: CONSOLE: 309093.988 ppr_get_vht_mcs: Failed ppr_t:00465314 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f4c
Sep 21 15:48:25 kernel: CONSOLE: 309093.997 ppr_get_vht_mcs: Failed ppr_t:00465314 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f4c
Sep 21 15:48:27 kernel: CONSOLE: 309095.635 ppr_get_vht_mcs: Failed ppr_t:00465314 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f3c
Sep 21 15:48:27 kernel: CONSOLE: 309096.228 ppr_get_vht_mcs: Failed ppr_t:00465314 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f4c
Sep 21 15:48:27 kernel: CONSOLE: 309096.256 ppr_get_vht_mcs: Failed ppr_t:00465314 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f4c
Sep 21 15:48:28 kernel: CONSOLE: 309096.807 ppr_get_vht_mcs: Failed ppr_t:00465314 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f4c
Sep 21 15:48:30 kernel: CONSOLE: 309098.681 ppr_get_vht_mcs: Failed ppr_t:00465314 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f3c
Sep 21 15:48:30 kernel: CONSOLE: 309098.954 ppr_get_vht_mcs: Failed ppr_t:00465314 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f3c
Sep 21 15:48:33 kernel: CONSOLE: 309102.315 ppr_get_vht_mcs: Failed ppr_t:00465314 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f4c
Sep 21 15:48:34 kernel: CONSOLE: 309102.538 ppr_get_vht_mcs: Failed ppr_t:00465314 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f4c
Sep 21 15:48:34 kernel: CONSOLE: 309102.625 ppr_get_vht_mcs: Failed ppr_t:00465314 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f4c
Sep 21 15:48:34 kernel: CONSOLE: 309102.758 ppr_get_vht_mcs: Failed ppr_t:00465314 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f4c
Sep 21 15:48:34 kernel: CONSOLE: 309103.243 ppr_get_vht_mcs: Failed ppr_t:00465314 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f4c
Sep 21 15:48:37 kernel: CONSOLE: 309105.685 ppr_get_vht_mcs: Failed ppr_t:00465314 BW:2 Nss:1 mode:0 TX_Chain:4 rateset:00175f4c