Performance analysis on nRF5340 PDK

[Rajat Kumar]

1. We are measuring our component performance on nRF5340 PDK and getting pretty high CPU load values. We are suspecting that our code and tables are sitting in flash memory rather than RAM. Is there anyway we can put our whole code fully in RAM and measure performance ?

2. Also the online Documentation mentions there are two modes for nRF5340 PDK (MODE=Cache) and (MODE=RAM). Cache mode can be used for performance profiling of code running in the system. How should we configure, to run our component in cache mode.

  

[Einar Thorsrud]

Hi,

Are you using the nRF Connect SDK? I will assume so for now.

1. It should be possible to configure code execution from RAM by setting CONFIG_XIP=n in prj.conf.

2. Cache mode is enabled by default by the soc.c implementation for nRF5340 in Zephyr (and thus nRF Connect SDK). If not using Zephyr, you can enable it yourself in the same way:

	/* Enable the instruction & data cache */
	NRF_CACHE->ENABLE = CACHE_ENABLE_ENABLE_Msk;

[Radhika Krishnan]

I tried enabling the parameter CONFIG_XIP=n in  both prj_nrf5340_dk_nrf5340_cpuapp.conf as well as prj.conf. But after building my project (zephyr/zephyr.elf), the final .config file in build_nrf5340_dk_nrf5340_cpuapp\zephyr still has the setting CONFIG_XIP=y in it. Is my option over written by some other script/file. How can we ensure our configuration is properly set.

[Einar Thorsrud]

Hi,

You are right. It does not work. XIP is forced on by zephyr\soc\arm\nordic_nrf\nrf53\Kconfig.series. Allowing it (by removing XIP there) does not work. I don't immediately see how it can be solved.