Re: The New GNUstep Seems Slow

[Fred Kiefer]

I just run kcachegrind over the callgrind result from Ink and from that 
I would pick out the new method [CairoFaceInfo characterSet] that Eric 
added on the 27th of March as the culprit. On my machine this seems to 
use up 90% of the execution time of Ink. I don't trust any profiling 
numbers, still this is an important hint, where the slowdown might come 
from.

I don't quite understand how this could happen, as this method gets 
called only once per font. The main time there is spend in FcFontMatch, 
which also gets called from fontFace, but doesn't result in a problem 
there. As it turns out FcFontMatch gets called 10 times (my not so 
scientific numbers, invent your own if you prefer) more often from 
characterSet than it is called from fontFace and the reason for this 
simply is that we cache the fontFace but not the characterSet. The 
solution should be as simple as to cache the characterSet as well. Or 
even better, use a common cache for the resolved pattern.

Eric, what is your thinking on this? By now you are more familiar with 
the cairo backend than I am.



On 28.04.2011 21:03, Richard Stonehouse wrote:
> This was with the cairo backend.
>
> Rebuilds with the art and xlib backends work fine - run at the
> expected speed.
>
> The installed cairo is libcairo.so.2.10800.10 from openSUSE 11.3
> package cairo-1.8.10-3.1.i586; gnustep-back 0.18.0 worked OK with
> this.
>
> There is another libcairo on the system, installed by vmware in one
> of its own directories, but I'm pretty confident that gnustep-back is
> linked against the correct libcairo and not the spurious one.
>
> openSUSE 11.4, which I've downloaded but not yet installed, has a new
> version of libcairo: /usr/lib/libcairo.so.2.11000.2 in package
> libcairo2-1.10.2-6.9.1.i586. I'm planning to install it over the
> weekend so will see whether the problem goes away.
>
> Please let me know if there's anything else I should try.
>
> On Thu, Apr 28, 2011 at 11:08:23AM +0100, Fred Kiefr wrote:
> > I don't know about any specific reason why GNUstep should now be
> > slower.  This seems to be an important issue to investigate.  Which
> > bacend are you using?  A wrong backend is the most common reason
> > for a slowdown.  If this isn't the case we need to use tools to
> > find out where the time gets spend.  I will send a mail on this
> > next week, when I am back home.