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 > > Cc: 26402@debbugs.gnu.org > > > >> 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 >