Re: Speed improvement of gnome-terminal

[Brian Cameron <Brian Cameron Sun COM>]

Geetha:

> There are concerns about the gnome-terminal speed. The display and
> refresh are a bit slow. 
> The gnome-terminal uses libvte backend.
> I rebuilt the gnome-terminal with libzvt(2.0.1-54.2) backend but did not
> find a significant speed improvement (thought it was faster). Further
> zvt does not provide i18n support. I downloaded the latest cvs zvt and
> rebuilt with that. But that seemed slower than vte.
> To improve the gnome-terminal speed there might be some optimizations
> which could be made on the backend libvte. Any other thoughts on this?
> Do drop in any suggestions for improving gnome-terminal speed... 

I suspect that the biggest performance boost that you could get out
of gnome-terminal would be to improve the way it interacts with the
Xserver.  I was recently working with the SunRay team and one of their
benchmarks showed that xterm used an average bandwidth consumption of
2kbs while gnome-terminal used an average of 35-38kbs.

The main reason for this difference is when the terminal scrolls xterm
uses an Xcopy operation to move the existing bits properly and only
actually renders the new text to be displayed.  gnome-terminal, on
the other hand, creates a new pixmap internally and creates a complete
new pixmaps for the entire terminal pane *each time* a scroll
operation happens.  In other words, when the terminal looks like it
is continuously scrolling a lot of output, it is doing this slow
operation over-and-over.

You would not notice much of an improvement with libzvt because it also
has the same issue.  It is probably slightly faster because it doesn't
display anti-aliased fonts, so the rendering time would be slightly less.
But, then, you also don't get anti-aliased fonts.

You might consider using xterm if you need a faster terminal program,
at least until this issue is corrected in vte.

--

Brian