android trace file on device

is it possible to create trace file on devices or can I use trace file only on emulator?

Cause I always get RT-Execption when I use Debug.startMethodTracing();

Here the Exception:

05-11 09:34:27.687: ERROR/AndroidRuntime(5599): java.lang.RuntimeException: 
Unable to open trace file '/sdcard/loop_locList开发者_StackOverflow中文版ener.trace': Permission denied

thanks