PMU(Performance Monitoring Unit) support on imx6

[ramappahugar]

Hi,

Working on imx6-sabresd (cortex-a9) board and Kernel - 4.1.15. Trying to do performance evaluation by making use of performance monitoring unit(PMU).

Enabled the PMU in dts file and also enabled the performance related kernel configurations. 

I'm running "perf stat ls" command on the target. I'm getting following output.

Performance counter stats for 'ls':

10.287337         task-clock (msec)                   #             0.428 CPUs utilized
52                      context-switches                     #             0.005 M/sec
0                        cpu-migrations                         #             0.000 K/sec
47                      page-faults                               #             0.005 M/sec
7766306            cycles                                      #             0.755 GHz
0                       stalled-cycles-frontend             #             0.00% frontend cycles idle
0                       stalled-cycles-backend            #             0.00% backend cycles idle
0                       instructions                               #             0.00 insns per cycle
0                       branches                                  #              0.000 K/sec
0                       branch-misses                         #              0.00% of all branches

0.024054000 seconds time elapsed

Always Bold letter entries values are zero (instructions & branches).

1. whether cortex-a9 based imx6 soc supports PMU ?

2. If it supports PMU, why these entries are zero ?

If I want to debug, where to look into the kernel ?

Please provide your views on it.

Thanks,

Ram

[saiyamdoshi]

Hello ramappahugar‌

I am facing problem in enabling PMU hardware events and looks like you have been successful in that. Can you please help me for my query - i.MX6 - No hardware perf events supported by kernel?

[Yuri]

Hello,

  Please refer to the following :

How to use oprofile in i.MX6 

Have a great day,

Yuri

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