dtrace discuss - Jun 2008 - System goes slow when starting xterm out of a terminal

Yes, I get this. Once the xterm is running everything is fine, but it takes ~30s
to start up and during this time the system is essentially unusable.
I''ve noticed during this time that the main fan on my speeds up yet the
harddisk light remains off. I''m guessing therefore that something
computationally intensive is occurring, yet there is no apparent paging going on
so whatever is happening isn''t causing any memory pressure.

Running prstat across an xterm start shows that process "Xorg/1" takes
up 100% of the CPU for the time. I guess this would be an interesting subject to
investigate using dtrace :-).

I''m running opensolaris on an old machine, 800MHz PIII with only 512Mb
of memory. I''m impressed how well it is working, other than this
apparent xterm issue.


--
This message posted from opensolaris.org

Hi,
> Running prstat across an xterm start shows that process "Xorg/1"
takes
> up 100% of the CPU for the time. I guess this would be an interesting
> subject to investigate using dtrace :-).
You may try to collect stack and try to guess where does Xorg spend
it''s
time. Something like

dtrace -n ''profile-1001 /pid == $target/ { @num[ustack()] = count();
}'' -p `pgrep Xorg`

Run this prior to xterm execution, and break the dtrace process once
xterm is running.

It will probably be long listing, so I recommend redirect output to file
using ''-o file''.

But generally I would recommend using sun studio performance analysis
tools ( make your X only start terminal and exit )

> I''m running opensolaris on an old machine, 800MHz PIII with only
512Mb
> of memory. I''m impressed how well it is working, other than this
> apparent xterm issue.
Using other terminal emulators is giving you the same issue, or they
start faster ? What graphic card are you using ?

-- 
	Vlad
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Vladimir Marek wrote:
> Hi,
> 
>> Running prstat across an xterm start shows that process
"Xorg/1" takes
>> up 100% of the CPU for the time. I guess this would be an interesting
>> subject to investigate using dtrace :-).
> 
> You may try to collect stack and try to guess where does Xorg spend
it''s
> time. Something like
> 
> dtrace -n ''profile-1001 /pid == $target/ { @num[ustack()] =
count(); }'' -p `pgrep Xorg`
> 
> Run this prior to xterm execution, and break the dtrace process once
> xterm is running.
Much of the analysis has already been done - see:
http://defect.opensolaris.org/bz/show_bug.cgi?id=1459

-- 
	-Alan Coopersmith-           alan.coopersmith at sun.com
	 Sun Microsystems, Inc. - X Window System Engineering