NRF_LOG_INFO print RTT Viewer is too slow

RE: NRF_LOG_INFO print RTT Viewer is too slow

BEN_HB — Tue, 09 Jul 2019 00:54:45 GMT

Thank you!

RE: NRF_LOG_INFO print RTT Viewer is too slow

Jørgen Holmefjord — Mon, 08 Jul 2019 11:43:08 GMT

Thank you for reporting back the solution. I'm not sure why this would slow down the logging, but you can see an explanation of what happens in this post.

RE: NRF_LOG_INFO print RTT Viewer is too slow

BEN_HB — Mon, 08 Jul 2019 09:51:00 GMT

now I found what is problem.

15.3.0 in sdK_config.h

NRF_FPRINTF_FLAG_AUTOMATIC_CR_ON_LF_ENABLED 1

this one is problem. maybe

I compare totally 15.3.0 and 15.2.0.

I check and chagne one by one config line.

and then NRF_FPRINTF_FLAG_AUTOMATIC_CR_ON_LF_ENABLED 0

print speed is normal.

I don't know why.

anyway if you know why it happend

please more explain to me.

Thank you

RE: NRF_LOG_INFO print RTT Viewer is too slow

BEN_HB — Mon, 08 Jul 2019 02:40:37 GMT

Thank you your reply.

First now I test ANT+ Communication using S332. I forgot telling you what I did.

I changed log option UART disabled and only RTT enable. but result is not change.

I download totally new SDK 15.2.0 and 15.3.0 on nordic ofiicial website. I used ant+ ant_bsc example.

first i did not chagne any option on sdk_config.h. on sdk_config.h log RTT is disable and uart is enable.

on this state, i build on 52832 PCA10040 1.2.1, nrf_log_info is not working. and when i enable log rtt, log_info is working regardless log_uart enable or not.

I disable log uart and enable log rtt. and same softdevice and same option.

15.2.0 is normal. it is almost real time print and that is what i wanted

however 15.3.0 is still slow print. I don't know what is problem. thanks your kindly answer.

RE: NRF_LOG_INFO print RTT Viewer is too slow

Jørgen Holmefjord — Fri, 05 Jul 2019 12:08:45 GMT

If you have bot UART and RTT backends enabled, this will be much slower than if you call the SEGGER_RTT functions directly. UART backend will transfer logs over UART peripheral, which by default runs at 115200 baudrate. RTT send logs over the debugger, which is typically running at 1-4 MHz. See Performance in the logger documentation for details about what you could expect with only RTT enabled and deferred vs. non-deferred.

Ideally, you should use deferred mode and process the logs when the chip is idle, unless you have timing-critical logs, then you can process the logs immediately by calling NRF_LOG_PROCESS/NRF_LOG_FLUSH.

RE: NRF_LOG_INFO print RTT Viewer is too slow

BEN_HB — Fri, 05 Jul 2019 01:40:22 GMT

HI.

1. I enabled

NRF_LOG_BACKEND_RTT_ENABLE, NRF_LOG_BACKEND_UART_ENABLE, NRF_LOG_ENABLE using CMSIS

Config file is too huge. which option do you need ?

I Test SEGGER_RTT_WriteString or SEGGER_RTT_PRINTF. it work very well.

I confused printf to UART or RTT? Could you recommand post to learn what difference and which config option need to enable or not.

In my opinion printf and segger_rtt_printf works well. maybe some option is conflicted.

Could you know only print NRF_LOG option? except other rtt or anything.

Thank you kind reply.

RE: NRF_LOG_INFO print RTT Viewer is too slow

Jørgen Holmefjord — Thu, 04 Jul 2019 14:15:32 GMT

Hi,

Can you post the configs you are using for NRF_LOG?
Do you have multiple backends enabled?
Do you print to RTT Terminal using printf also, or did you use this to print to UART?
Are you sure that the configs are identical for SDK 15.2.0 and SDK 15.3.0? I do not think that there should be any major changes in the logger module.

NRF_LOG_info is written using macros, so it should be faster than printf, which use variable argument list (__VA_ARGS__).

Best regards,
Jørgen