Xorg 7 uses much more CPU than Xorg 6

[Peter Jeremy]

On Mon, Apr 14, 2008 at 09:50:20PM -0500, Eric van Gyzen wrote:
>I also ran "yes" with an 80-character argument and ran top to watch CPU 
>usage.  After top reached a steady state, I recorded the following:

Note that it's very difficult to see differences in performance with
this test - in either case, the system is flat out but there's no
indication of how fast it's processing.  You might like to experiment
with ports/x11/x11perf

>==== Xorg 6 ====
>CPU states: 67.3% user,  0.0% nice, 32.7% system,  0.0% interrupt,  0.0% idle
>
>==== Xorg 7 ====
>CPU states: 25.9% user,  0.0% nice, 74.1% system,  0.0% interrupt,  0.0% idle

The most striking thing to me is the difference in system time.  You
might like to ktrace both Xorg's whilst doing some fixed workload and
compare the system calls.  There was a recent thread about Xorg doing
lots of gettimeofday(2) syscalls due to a configure error and possibly
you are hitting this or a related issue.

-- 
Peter Jeremy
Please excuse any delays as the result of my ISP's inability to implement
an MTA that is either RFC2821-compliant or matches their claimed behaviour.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 195 bytes
Desc: not available
Url : http://lists.freebsd.org/pipermail/freebsd-x11/attachments/20080415/5d97da6f/attachment.pgp