pc-ble-driver-py throughput issues with write_req()

RE: pc-ble-driver-py throughput issues with write_req()

grantrudd — Tue, 18 Oct 2022 14:49:37 GMT

Hi SIgurd,

Thanks for confirming that the pc-ble-driver-py library is behaving properly. I was able to figure out the issue with my application and now am seeing the expected results.

Thanks,

Grant

RE: pc-ble-driver-py throughput issues with write_req()

Sigurd — Mon, 17 Oct 2022 11:24:14 GMT

Hi,

[quote user="grantrudd"]And here is the sniffer trace from when the devices connect and part of the DFU.[/quote]

Not sure how you are measuring this, but what's happening on-air is as expected though,

the write response is received in the next connection event. And a new write request is sent.

RE: pc-ble-driver-py throughput issues with write_req()

grantrudd — Thu, 13 Oct 2022 16:30:18 GMT

Hi Sigurd,

Here is the return from get_connectivity_hex_version():

>>> config.get_connectivity_hex_version()
'4.1.4'

And here is the sniffer trace from when the devices connect and part of the DFU.

devzone.nordicsemi.com/.../4505.trace.pcapng

Thanks,

Grant

RE: pc-ble-driver-py throughput issues with write_req()

Sigurd — Thu, 13 Oct 2022 07:58:23 GMT

Hi,

1) Could you check what get_connectivity_hex_version() returns?

2) If you have a spare DK or dongle, could you capture a sniffer trace? https://www.nordicsemi.com/Products/Development-tools/nrf-sniffer-for-bluetooth-le

RE: pc-ble-driver-py throughput issues with write_req()

grantrudd — Wed, 12 Oct 2022 14:25:51 GMT

Hi Sigurd,

I am still seeing this issue on v0.17.0, with Python 3.8 running an a machine with Ubuntu 22.04. I installed a fresh copy of pc-ble-driver-py from pip this morning and am still seeing slow performance with write_req().

This is what I'm seeing for timing with the connection parameters mentioned above:

write_req() time 0.05992388725280762
write_req() time 0.05992531776428223
write_req() time 0.059960365295410156
write_req() time 0.05984926223754883
write_req() time 0.05991005897521973
write_req() time 0.05988287925720215
write_req() time 0.059864044189453125

Is there a way to check the version of _nrf_ble_driver_sd_api.so (which I assume is the shared library created from pc-ble-driver-py)? The documentation at the top of the associated python file still says 4.0.1.

# This file was automatically generated by SWIG (http://www.swig.org).
# Version 4.0.1
#
# Do not make changes to this file unless you know what you are doing--modify
# the SWIG interface file instead.

RE: pc-ble-driver-py throughput issues with write_req()

Sigurd — Wed, 12 Oct 2022 11:28:26 GMT

Hi,

[quote user=""]I am currently working with pc-ble-driver-py and have observed write operations taking an exceedingly long time. Previous DevZone posts on this topic seem to be unresolved:[/quote]

We fixed the speed issue in this PR: https://github.com/NordicSemiconductor/pc-ble-driver/pull/264

The fix is released in pc-ble-driver v4.1.4, which is used in pc-ble-driver-py starting from v0.16.1

https://github.com/NordicSemiconductor/pc-ble-driver-py/commit/1242ae2281a3c0d01f435e2dcf0e5aec16171028