bug#18522: 24.4.50; mapcar is very slow

[Eli Zaretskii]

> From: Peter Münster <pmlists@free.fr>
> Cc: rudalics@gmx.at,  larsi@gnus.org,  18522@debbugs.gnu.org
> Date: Wed, 24 Feb 2016 11:25:10 +0100
> 
> On Tue, Feb 23 2016, Eli Zaretskii wrote:
> 
> > We need to time that loop to be sure.  Can you do that with 'perf', 
> 
> How please?

"perf annotate", perhaps?

> > or add a call to gettimeofday before and after, and see how much time
> > it takes as the list of buffers grows?
> 
> Then, I would need to restart emacs. If it's possible to measure the
> time without restarting it, that would be better.

Yes, of course.