I am want to use arm pmu to profile checksum algorithm performance, but the event counter always return 0, only cycle counter is normal.
The step i use as follows:
1. enable user enable by setting PMUSERENR.E bit
2. enable pmu enable by setting PMCR.E bit and event counter and reset cycle, event counter
3. set PMSELR and PMXEVTYPER
4. run checksum algorithm
5. read cpu cycle count and event counter
I found some people say reruires set SDER as 0b11, but i follow this, still no effect.
Does any step i have omit or whether it requires setting some other register before read event counter?
I use MTK platform with armv7 cortex-A53 to profile checksum algorith performance .