How to measure performance inside Kernel?
From: peter.senna@gmail.com (Peter Senna Tschudin)
Date: 2012-02-10 21:47:37
Dear list,
As Michi suggested, I did some testing with ktime.h, but I found a
simpler solution with time.h.
I'm not sure if it is correct, and I would like to have some help... :-)
The code that I'm using for execution time measurement is:
#include <linux/time.h>
getnstimeofday (ts_start); /*stopwatch start*/
for (i = 0; i < q->num_buffers; ++i)
q->bufs[i]->state = VB2_BUF_STATE_DEQUEUED;
getnstimeofday (ts_end); /*stopwatch stop*/
diff = timespec_sub(end, begin);
printk ("%lu,", diff.tv_nsec );
Am I doing anything wrong? Can mysterious stuff like out of order
execution engine, brake the stopwatch?
The full module code is at: http://goo.gl/cCMIa
Thank you!
Peter
On Thu, Feb 9, 2012 at 10:58 AM, Peter Senna Tschudin
[off-list ref] wrote:Dear list, I'm looking for a way to compare the performance of two different codes inside Kernel. I was able to do some comparison on user land but I want to test the specific portion of code inside Kernel.
-- Peter Senna Tschudin peter.senna at gmail.com gpg id: 48274C36