Hi!

On 10:58 Thu 09 Feb     , Peter Senna Tschudin wrote:
...

But I want to repeat the tests on specific portion of code, not on
entire application. Is there a safe way of do something like:

start_bench ( ?? ); /* start measurement */

buf_ptr_end = q->bufs[q->num_buffers];

for (buf_ptr = q->bufs[0]; buf_ptr < buf_ptr_end; ++buf_ptr)
       buf_ptr->state = VB2_BUF_STATE_DEQUEUED;

end_bench ( ?? ); /* end measurement */

Yes, you can do this. If you search for a way for time measurement, take a
look at include/linux/ktime.h .

And is this the correct approach for testing the performance of
specific portion of Kernel code?

Why not? I would be a be worried about how the cpu-cache effects the
measurement, especially because your benchmark already showed that a
significant time is spent there.

	-Michi
-- 
programing a layer 3+4 network protocol for mesh networks
see http://michaelblizek.twilightparadox.com