Strange.. topology folder is not present in my sysfs. Here is the strace logs from the failure func.

newfstatat(AT_FDCWD, "/sys/devices/system/cpu/cpu0/topology", 0xbeb04668, 0) = -1 ENOENT (No such file or directory)
close(3)                                = 0
writev(2, [{"topo_folder_scan", 16}, {": ", 2}, {"No such file or directory", 25}, {"\n", 1}], 4topo_folder_scan: No such file or directory
) = 44
mprotect(0xb6f0d000, 4096, PROT_READ|PROT_WRITE) = 0
mprotect(0xb6f0d000, 4096, PROT_READ)   = 0
write(2, "Failed to read CPU topology info"..., 45Failed to read CPU topology info from sysfs.
) = 45
mprotect(0xb6f0d000, 4096, PROT_READ|PROT_WRITE) = 0
mprotect(0xb6f0d000, 4096, PROT_READ)   = 0
close(0)                                = 0
close(1)                                = 0
close(2)                                = 0


On Tue, Jul 7, 2015 at 1:18 PM, Daniel Lezcano <daniel.lezcano@linaro.org> wrote:
On 07/07/2015 08:13 AM, $rik@nth  wrote:
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.


 Please use strace and give the tail of the traces, especially the failing system call.

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 <mailto: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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Thanks & Regards,
M.Srikanth Kumar.


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Thanks & Regards,
M.Srikanth Kumar.