NRF_LOG_INFO print RTT Viewer is too slow

[BEN_HB]

HI. i use SEGGER Studio and SDK 15.3.0.

I usally use printf func for debug. however as use SDK func, I need to use NRF_LOG_INFO casue SDK file use NRF_LOG_INFO for debuing.

and I search how enable and it work. but the speed of print is slow. 

i compare printf vs nrf_log_info using 

for(; ;) { printf("A\n")} and for(; ;) { NRF_LOG_INFO("A\n")}

nrf_log_info also print log, but not enough speed to check real-time.

i try to change buffer size or deferred option. it is no change.

help me what problem 

Thank you.

add) i test SDK 15.2.0 it work very well. not slow 

[Jørgen Holmefjord]

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

[BEN_HB]

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.