Slow DFU speed

RE: Slow DFU speed

Hung Bui — Fri, 23 Jun 2017 07:19:02 GMT

The relatively low through put on the S8 due to we don't implement Bluetooth 4.2 or 5.0 on the DFU bootloader as we want it to be compatible with older device. Usually the max through put on Bluetooth 4.1 is about 16kB/s. But you won't be able to get to that value because the phone doesn't want to give the full time domain for BLE also it would prefer to save the power consumption.

If you want to test thoughput, I would suggest to use our throughput test example in the SDK.

RE: Slow DFU speed

Superkurt — Thu, 22 Jun 2017 18:40:28 GMT

Thanks for looking into that. Good to know that's also on a Galaxy S8 the throughput is "only" 4kB/s. I'll test it on other phones. Currently I've no device for getting the sniffer trace. Thanks for your help so far.

RE: Slow DFU speed

Hung Bui — Thu, 22 Jun 2017 14:15:29 GMT

It's the Android's log, not the sniffer trace. It seems that the connection interval was 48ms and only 1 packet per connection interval. If I have the sniffer trace, I can find the reason why it's not updated to 30ms.

Most likely it's the phone's limitation.

RE: Slow DFU speed

Superkurt — Thu, 22 Jun 2017 14:09:57 GMT

Hi Hung Bui,

I've captured the packets directly on the smartphone via activating the bluetooth logging in the developer options. I've attached the log. You can open the log with wireshark.

thingyDfu.log

Hope that helps.

RE: Slow DFU speed

Hung Bui — Thu, 22 Jun 2017 08:40:37 GMT

Hi Superkurt,

It's odd that the speed was only 0.4kB/s. We need to have a look at the sniffer trace to see how many packet was sent on every connection event/interval. Usually we see 4 to 6 packets. If the connection interval is set at 30ms, the throughput should be around 2.6kB/s.

Note that not all the time we have full control of what configuration the phone should use. The app has limited access to BLE stack on the phone.

I'm seeing here throughput of 4kB/s with my Galaxy S8.