Subject: Re: bug#26402: 25.2; Font rendering extremely slow on any non-default font

From: Gennady Uraltsev <[email-masked]>
Date: Sun, 9 Apr 2017 13:07:03 +0200

Dear Eli,

1) I must admit that I am not very familiar with GDB. I have done some
programming so I am familiar with the basic concepts but not the tool.
If you give me an outline of what to do I can try to do it (I do not
mean step by step instructions, I guess I can figure something out and
if I really can't I could ask for clarifications).

2) Currently this is what I am doing. I have some virtual machines of
otherdistributions (vanilla installations) that I use to test for bugs
(cross-check).

I see that on kubuntu 16.10 with emacs 24.5.1 and with emacs25.1.2 the
problem does not appear: everything works smoothly.

3) Just a question: is there a way to ask emacs to dump the info about
the versions of all the libraries it uses?

Let me know what to do.

Thanks!

Gena

On 09/04/17 11:45, Eli Zaretskii wrote:
> > Date: Sun, 09 Apr 2017 08:44:55 +0300
> > From: Eli Zaretskii <[email-masked]>
> > Cc: [email-masked]
> >
> >> The profiler profiles are attached.
> >
> > The profiles clearly tell the problem is related to font metrics, but
> > they don't tell what exactly causes the slow-down or why.  Sorry.
>
> How proficient are you with using GDB?  If I ask you to step through a
> certain Emacs function and tell which of its parts is the slow one,
> can you do that?  I can give more detailed instructions if needed.
>
> TIA
>