Performance drop on Wifi (30%) and BT (60%) with latest build?

[cyberman54]

I am using this Arduino core for wifi and bluetooth packet sniffing on ESP32 devies, using monitor mode of ESP32 wifi stack and using ESP32 BT/BLE stack. The project can be found here.

I assessed that with latest build of arduino-esp32 core the overall performance on both wifi and bt sniffing decreased dramatically.

Test setup was 2 identical hardware boards with identical application software, but one build using arduino-esp32 core version 2.10000.0 (version number in platformio) and other one build using latest code of this repo by 26th Nov. 18.

The board build with latest code sniffs ~60% less bluetooth and ~30% less wifi devices compared with that one build on older code (under same conditions in same time).

I have no idea how to further analyze this. Since both BT and Wifi are affected this could mean a general performance drop on core 0 (running BT and Wifi stack), or a problem with the 2,4 GHz radio driver?

My code for bt and wifi sniffing can be found here:

Wifi sniffing
BT sniffing

[kscheff]

Have you tried to swap the boards in order to verify if it is not an issue with the hardware?

[cyberman54]

I tried with several boards before, because i expected a hardware problem. It's clearly reproducable on different kind of hardware, the drop comes in when comparing code running on newest core.

[chegewara]

Im not saying it is, but it may be because change in SW coex settings as per my suggestion was changed to wifi performance. In other hand you report that both, bt and wifi performance drop.
I tested yesterday ble library performance with new arduino-esp32 and i can send notifications in very tight loop, with only 3ms(maybe even 2ms) delay without packet drop or congest event.

[cyberman54]

@chegawara my code does not send any data neither on BT nor on Wifi, it uses only the monitor mode for sniffing. I think 2-3ms is for sniffing a very long time, i guess the monitor mode packet capture driver on esp32 will run much faster. So we may see here a performance problem on low layer. Any ideas how to further analyze this?

[chegewara]

I would rather try to open issue in esp-idf repo, because like you said it can be in low level driver.

[cyberman54]

I did intentionally open this issue here, because as far a i can see with platformio both my build version are based on same version of ESP-IDF core. So it looks like it must be something came in with latest changes in arduino-esp32 core. Maybe something which causes side effekt on esp32 drivers.

[cyberman54]

@chegewara : could you please point me to the code affected by "change in SW coex settings as per my suggestion"? I would like try to check if this change could have impact on my use case.

[chegewara]

This is change in arduino-esp32 v1.0.1-rc1 im talking about:
https://github.com/espressif/arduino-esp32/blob/master/tools/sdk/sdkconfig#L346-L350

It changes some bt and wifi library, but i dont know how.

[cyberman54]

@chegewara Thank you very much for this pointer. Since the change came in exactly at the same time when i discovered the issue in my software, i think it is the hot scent to the magic what happened.
I will try with different coexist settings.
Didn't find any descriptions on how that coexist settings work. It seems the coexist functions are only forward declared in the source code and point to a precompiled library of the esp32 wifi stack:

https://github.com/espressif/esp32-wifi-lib/blob/master/libcoexist.a

[cyberman54]

@chegewara i tested different coexist settings by switching it during runtime with esp_coex_preference_set(coexist_config). But does not show any effect on my sniffing results. Still far lower sniffing results than with previous build. This is annoying :-(

Maybe @nkolban can help here?

[chegewara]

Kolban is busy and is not working with esp32 or ble now.

[copercini]

empirically saying: the best results for BLE scan here is when SW coexistence is fully disabled, using only HW switching (ie. it disables BLE for a while and use the radio for wifi, then disables wifi and uses BLE...), this doens't work for classical BT, only BLE+Wifi

[cyberman54]

@copercini my sniffer is using Wifi+BT+BLE in parallel. How can disable SW coexist from within arduino-esp32 framework?

[copercini]

@cyberman54 no, AFIK you can't use Wifi+BT without SW coexistence =/