[Pkg-xfce-devel] Bug#453266: Bug#453266: Bug#453266: xfce4-terminal: text displays slowly and hogs CPU in some tabs and instances

[Yves-Alexis Perez]

On sam, 2007-12-01 at 23:35 -0500, A. Costa wrote:
> On Fri, 30 Nov 2007 10:37:02 +0100
> Yves-Alexis Perez <corsac at corsac.net> wrote:
> 
> > Could you test « by hand » ...gnome-terminal...
> 
> Have done so but the results seem inconclusive.  I get results that
> for 'seq 1000000' range over {9,14,15,46,52} seconds real time.  I
> opened about 50 tabs, that was the '14'.
> 
> Note that I had background processes going at the time, which might
> account for it, but maybe not.  Anyway, none of these runs compared
> to the 'xfce4-terminal' slowness.
> 
> I haven't seen the 'xfce4-terminal' slowness in the last few days.

Ok so it doesn't seem really consistent :/
> 
> Retesting today... new instance, 1st tab 84s, run again 81s, 2nd tab
> 89s.  Takes too long, I'll knock off a '0'.  ' seq 100000' 2nd tab 9s,
> 9s, 9s; back to first 9s, 9s; hmmm, opened 50 tabs, 50th tab 39s, 37s;
> try another 50, 100th tab slow at first but sped up -- 9s, 9s, 8s...
> that starting slowness, if I do 'seq 10000' it takes 6s,8s,6s,6s,5s,6s,
> adding a zero, back to 9s.  Add a zero, 19s,20s,22s,17s.
> 
> The 6s for the 'seq 10000' in tab 100 looks like the kind of thing I had 
> before.  
> 
> Tried tab 2 'seq 10000' in GnTerm again, 10s,0.7s,0.7s,0.7s.  Tab 50
> 8s,8s,7s,9s. Opening tab 100 9s,4s,4s; try 'seq 100000', 8s,10s,7s.
> 
> In a nutshell, with many tabs, I see that the output speed of 'seq' is
> not a flat line... it begins slowly then speeds up, by the looks of it
> there seems to be two speeds or "gears", low gear 'seq 10000' 6s
> (=~1800per/sec), high gear 999000 in 19-6=13s (=~.77000p/s).

Note that it may have to do with the number of lines you keep in buffer
(see terminal preferences). When you first run a command wich outputs a
lot, the terminal will have to allocate the memory. Then it'll reuse the
memory already allocated, so it'll be faster.
> 

> 	% grep Composite /etc/X11/xorg.conf ; echo $?
> 	1
> 
> It is and was enabled.

ok
> 
> > On xfwm you need to check in Settings Manager, Window Manager tweaks,
> > tab « compositing » (wont be there if compositing is disabled in
> > xorg).
> 
> Well the 'compositing' tab exists and under it there's an unchecked box
> "Enable display compositing".  It still needs to be off in X then?
> Either way I'll test it soon... (but can't right now).

Yes, it's activated in xorg but not in xfwm. Some people have reported
that having compositing enabled but without compositor running can sow
things a lot. Test it with compositing enabled in xfwm, and report back.
Then test with compositing disabled in xorg, and report too.

Anyway, it'll be slower when compositing is activated in xorg.

> PS: is there a way to automate opening a lot of tabs from the command
> line and adding a command?  That is, a way to tell the terminal "open
> a window, then open 50 tabs, and in the 50th run 'foo'".  'expect' could
> probably do it, but maybe there's some other way.

Not really.

Yet, I don't think it's a bug in terminal wich prevents you to use it.
This kind of test just stress it a lot but any terminal will be more
cpu-intensive when a lot of text is outputed fastly.

Cheers,
-- 
Yves-Alexis Perez