SDK 15.2 to SDK 15.3 migration bug in FreeRTOS

[abhipray]

When we ported our FreeRTOS based project to SDK 15.3 from 15.2, we noticed a big jump in the CPU Usage. It turned out that the issue was in SDK 15.3's freertos port_cmsis_systick.c. In SDK 15.2, the use of sd_app_evt_wait() for sleeping was disabled because "With FreeRTOS sd_app_evt_wait increases power consumption with FreeRTOS compared to _WFE (NRFFOSDK-11174)". In SDK 15.3 sd_app_evt_wait() is being used leading to the high CPU usage that we noticed. 

Why was that done? Is there a way to use sd_app_evt_wait() with SDK 15.3 and FreeRTOS that does not increase power consumption that I am missing?

Thanks

[kirkus]

I noticed the same thing on my project with 15.3, and when I implemented an FPU_IRQHandler as mentioned here, my CPU usage and power consumption dropped significantly.