Code execution time

[TAR CHAL]

Hi,

I'am using sdk14.2 with S140 V5.0.2-alpha.

I want to measure a time execution of a snippet code (ciphering function), and i want to display the time value with NRF_LOG_INFO, or SEGGER_rtt.

i know that there are other methods like toggling GPIO and then use a logic analyzer to visualize  the timing, but i don't have a logic analyzer.

Can any body propose me a method to proceed?

[Jørgen Holmefjord]

Hi,

You can setup the application timer library, and use the functions app_timer_cnt_get before and after your function call, and app_timer_cnt_diff_compute at the end to compute the time spent by the function. Note that this will give you the value in ticks, and you will have to calculate the actual time if you need this. Also note that if any interrupts happens within the function, the time spent handling the interrupts will also be counted.

Best regards,
Jørgen

[Jørgen Holmefjord]

You need the RTC to be running in order to get values. Please make sure you set the SDK config macro described in this post, and start a "dummy timer" to make sure the RTC is started.

[TAR CHAL]

yes you right, the RTC in the sdk config was disabled, but when i enabled it and rebuiled my app, still have the same problem!!!!!

[Jørgen Holmefjord]

Did you also create and start a "dummy timer", to make sure RTC is running? RTC will not start until a timer is created, even it you have set the config. The config is also needed to make sure the RTC is not stopped if the last timer is stopped, but by leaving the "dummy timer" running, you make sure this never happens anyway.

[TAR CHAL]

thanks, after timer start i have a value of 8 ticks for begining and 12 ticks for the end, 4 ticks to realize the cifer and 4ticks = 91us, i think that it's pretty good for a cortex m4f,