[xdebug-general] trace.xt but No cachegrind.out

Dear all,

I just installed on my ubuntu workstation xdebug and Kcachegrind.
I set in php.ini :
extension, profiler_output_dir and profiler_enable

when I run a simple php file I have nothing in the /tmp dir

when I put in a php file :
xdebug_enable();
xdebug_start_trace();
I have a trace.numbers.xt file, but no cachegrind.out file

I made a lot of search on internet but nothing....

Can you help me ?

Many thanks

Thomas

--