Slow DFU using nrfutil

RE: Slow DFU using nrfutil

Vidar Berg — Wed, 24 Feb 2021 12:00:56 GMT

Hello,

OK, it's good to know that it performs better on VMs as well. Thanks for confirming that. I thought maybe it had to be run natively.

[quote user="Michal L."]What exactly is bottleneck in Windows? I thought it is just matter of DK running Connectivity firmware and that nrfutil just sends data to the kit via UART. Or am I wrong?[/quote]

You are not wrong. I believe the problem with Windows is that the USB commands and responses are sent and received too slow. The required USB bandwidth is not much, but latency is more critical as the interface protocol requires transmissions and reception of many small packets.

RE: Slow DFU using nrfutil

Michal L. — Wed, 24 Feb 2021 09:10:02 GMT

Hello,

I finally had time to test it on Linux PC (actually Linux running in VirtualBox). And results are really much better than in Windows - whole update lasts ca 45 sec. in Linux (same update package lasts 11 min. in Windows).

What exactly is bottleneck in Windows? I thought it is just matter of DK running Connectivity firmware and that nrfutil just sends data to the kit via UART. Or am I wrong?

RE: Slow DFU using nrfutil

Vidar Berg — Tue, 16 Feb 2021 15:18:33 GMT

Hello,

Sorry for the delayed response. I have done some investigations on my own now, and I am starting to suspect it may have something to do with the USB stack on Windows. The reason for this is that I'm seeing much higher throughput when I test DFU on my Linux PC with the exact same script. Also, modifying the connection parameters in the script did not have any noticeable impact on the transfer speed for windows ( implying it's not bottlnecked by the connection configuration).

Multiple DFU payload packets per connection event on Linux

And less than one paylod packet per connection interval on Windows

Do you have a PC running linux natively that you can try this on?

RE: Slow DFU using nrfutil

Michal L. — Tue, 09 Feb 2021 09:58:34 GMT

Hello,

do you have any updates?

RE: Slow DFU using nrfutil

Michal L. — Wed, 13 Jan 2021 08:50:55 GMT

Thank you for the information.

RE: Slow DFU using nrfutil

Vidar Berg — Mon, 11 Jan 2021 10:44:56 GMT

Yes, unfortunately, this seems to be as expected as nRF connect on desktop/nrfutil is not capable of sending as many BLE packets per connection event as iOS and Android is. I will report this internally and request that we try to remove this limitation.

RE: Slow DFU using nrfutil

Michal L. — Tue, 05 Jan 2021 12:10:41 GMT

I've just tried update of the same file via nRF Connect on iOS and it took less then one minute to update. In the app I see that update is divided into 25 data objects and each object is transmitted every 2-3 seconds.

devzone.nordicsemi.com/.../RPReplay_5F00_Final1609848038.mp4

RE: Slow DFU using nrfutil

Michal L. — Tue, 05 Jan 2021 11:36:52 GMT

Hello Vidar,

thank you for testing. I just tested it with nRF Connect v3.6.1 and updated device running on SDK v12.0.0 based application and bootloader. And update speed is about 0.20 kB/s.

As I said, using nRF Connect on iOS or some Android phone it is much faster (I would say maybe 10x faster, but I can measure it, if needed).

RE: Slow DFU using nrfutil

Vidar Berg — Mon, 21 Dec 2020 08:04:13 GMT

Hello,

Sorry for the delayed response. I've done some testing with SDK 12.3.0 now, and in my case, it took about three times longer to do DFU from nRF connect on desktop compared to when I tested DFU with nRF connect on iOS. The reason for this discrepancy is likely due to the fact that the pc apps can send fewer packets per connection event. But, the throughput on nRF connect for desktop averaged at around 0.4 KB/s, so for me it would "only" take ~4 minutes to upload a 100k image. Do you see a lower transfer speed in nrf connect?

nRF connect for desktop SDK 12.3.0

nRF connect for desktop with SDK 17.0.2 for comparison ( supports long ATT MTU)

RE: Slow DFU using nrfutil

Michal L. — Thu, 17 Dec 2020 11:07:24 GMT

Today I tried to downgrade to pc-ble-driver-py v0.14.1 and pc-nrfutil v6.0.1 and compile executable nrfutil. Behaviour is still the same, update still lasts 10 minutes.

Florian Zierer wrote here that in his case in v6.0.1 problem was solved, so I don't know, what could be wrong now..

RE: Slow DFU using nrfutil

Michal L. — Wed, 16 Dec 2020 15:40:08 GMT

Hello Vidar,

it is based on SDK 12.0.0. We have no problems with update via nRF Connect on smartphone, also we have some application from external partner for our products and update here also works ok, so it looks it should be about some settings in nrfutil or connectivity firmware?

RE: Slow DFU using nrfutil

Vidar Berg — Wed, 16 Dec 2020 15:33:29 GMT

Hi,

DFU with pc-nrfutil is known to be quite slow, but nRF connect on windows should be on par with nRF connect on Android and iOS, so that's more suprising. Which SDK is the bootloader on the target based on?

Thanks,

Vidar