Why is my MP135 program running so slowly?

[morthy]

my code only made changes the io, no rtos, no interrupt, but it cost over 1 us.  the picture is that io sta. and clock

[PatrickF · Accepted solution]

Hi @morthy 

maybe you missed to enable the I & D caches ?

Regards.

[morthy]

oh,you are right, after i enable the cache,the runtime speed doubled.

[morthy]

thank you

[PatrickF]

Hi,

only doubled ?

I guess only Instruction cache were enabled (as it is simple as set a bit).

Data cache might bring more perf (e.g. write to GPIO section will be posted, so 0 waits), but this need to setup MMU with correct regions (usually sections attributes are : memories as "NORMAL", peripherals as "DEVICE" ).
I'm not fully knowledgeable on how to do it with HAL, but I assume functions to do such exists (maybe examples).

Regards.

[morthy]

When running the DDR example in STM32Cube_FW_MP13_V1.1.0, it takes 1.25us. after manually enabling the cache, the runtime is about 660ns. however, after downloading x-cube-freertos-mpu from GitHub and running the same code, the runtime is approximately 220ns.the rtos project exactly enable MMU and Cache