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Bug 532240 - gnome-terminal generates high cpu usage
gnome-terminal generates high cpu usage
Status: RESOLVED NOTGNOME
Product: gnome-terminal
Classification: Core
Component: general
2.18.x
Other All
: Normal major
: ---
Assigned To: GNOME Terminal Maintainers
GNOME Terminal Maintainers
Depends on:
Blocks:
 
 
Reported: 2008-05-08 20:38 UTC by Albert Zeyer
Modified: 2008-06-17 00:21 UTC
See Also:
GNOME target: ---
GNOME version: 2.19/2.20



Description Albert Zeyer 2008-05-08 20:38:14 UTC
Please describe the problem:
Gnome-Terminal generates high CPU usage when there is a lot of output.

I have a 2.16ghz Intel Dual core. There is a process running in a
gnome-terminal which itself does not take much CPU usage but generates a lot of
output (perhaps 100 lines / second). In such case, Xorg-Server has very high
CPU usage: between >50% on both CPUs if Gnome-Terminal is in the foreground or
~30% on both CPUs if it is in the background.

Could it be that on every change in the output, Gnome-Terminal sends the
*whole* data (everything in the textbox) to Xorg? That would explain the high
CPU usage.

On older systems (that bug occurs for me on all my systems), such a case is
almost like a DoS-attack, the mouse is almost not moveable anymore.


Steps to reproduce:
1. Start Gnome-Terminal.
2. Start any application which generates a lot of output.



Actual results:
CPU usage rises high.

Expected results:
No change, a stable system.

Does this happen every time?
Yes.

Other information:
Bug is filled also in the Gentoo bugtracker here:
http://bugs.gentoo.org/show_bug.cgi?id=220995
Comment 1 Christian Persch 2008-06-16 13:12:10 UTC
Which version of g-t and libvte is this with? Did you try with the latest versions?
Comment 2 Mart Raudsepp 2008-06-17 00:21:43 UTC
Per the downstream bug, this is a typical (at least until xorg-server-1.5) EXA performance problem. I see this myself as well on a radeon card (the reporter has an intel card) with EXA, but not really with XAA. If interested you will find sysprof profiles from the referenced Gentoo bug that show the time is spent in libexa.
We will follow-up there, and marking this as NOTGNOME, as the problem is most likely xorg-server/drivers.