I realized that i am using pretty old version of idlestat. After fetching latest version from [1] i am getting cpu topo read error. 

topo_folder_scan: No such file or directory
Failed to read CPU topology info from sysfs.

My sysfs entries are

root@eng-bld:/ # ls -l /sys/devices/system/cpu/
drwxr-xr-x root     root              1970-01-01 06:12 cpu0
drwxr-xr-x root     root              1970-01-01 06:13 cpu1
drwxr-xr-x root     root              1970-01-01 06:13 cpu2
drwxr-xr-x root     root              1970-01-01 06:13 cpu3
drwxr-xr-x root     root              1970-01-01 06:12 cpu4
drwxr-xr-x root     root              1970-01-01 06:12 cpu5
drwxr-xr-x root     root              1970-01-01 06:12 cpu6
drwxr-xr-x root     root              1970-01-01 06:12 cpu7
drwxr-xr-x root     root              1970-01-01 06:12 cpufreq
drwxr-xr-x root     root              1970-01-01 06:12 cpuidle
-r--r--r-- root     root         4096 1970-01-01 06:12 kernel_max
-r--r--r-- root     root         4096 1970-01-01 06:12 offline
-r--r--r-- root     root         4096 1970-01-01 06:12 online
-r--r--r-- root     root         4096 1970-01-01 06:12 possible
drwxr-xr-x root     root              1970-01-01 06:12 power
-r--r--r-- root     root         4096 1970-01-01 06:12 present
-rw-r--r-- root     root         4096 1970-01-01 06:12 uevent


[1] http://git.linaro.org/power/idlestat.git

On Mon, Jul 6, 2015 at 8:17 PM, Daniel Lezcano <daniel.lezcano@linaro.org> wrote:
On 07/06/2015 04:42 PM, $rik@nth  wrote:
Hi Linaro Dev team,

I  am trying to debug some scheduler changes on my new QUalcomm
snapdragon development board. To debug it further, i have cross compiled
the idlestat and tried to run for collecting traces. But it shows
segfault right after starting it with `idlestat --trace -f
/sdcard/mytrace -t 10 -p -c -w -- cyclictest

Pagefault logs can be found here [1] . Any suggestions will be much
appreciated.

 Hi,

thanks for reporting the issue.

Could you compile idlestat with the debug info, set the core limit (ulimit -c unlimited), run the idlestat again ? That will generate a 'core' file which we can exploit to do further investigation.

Otherwise run it with 'gdb' and then give the portion of code where the segfault occurs.

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