Duration

Here is an example to measure duration of a function call.

global time
probe vfs.read
{
    time[tid()] = gettimeofday_ns();
}
probe vfs.read.return
{
    if(time[tid()]) {
        printf("vfs.read by %s took %d ns to execute\n",
            execname(), gettimeofday_ns() - time[tid()]);
        delete time[tid()];
        exit();
    }
}