Subject: bug#18522: 24.4.50; mapcar is very slow

From: Peter Münster <[email-masked]>
Date: Mon, 22 Sep 2014 15:47:56 +0200

On Mon, Sep 22 2014, Stefan Monnier wrote:

> the time for mapcar includes the time spent in the function passed to
> mapcar, which is where most of the time is likely spent anyway.

Yes. The function is:

	         (lambda (header) (gnus-float-time
				   (gnus-date-get-time
				    (mail-header-date header))))

I've checked all 3 functions (gnus-float-time, gnus-date-get-time and
mail-header-date) with ELP, but emacs did not spend any significant time
in these 3 functions...

> Could you use the native, sampling, profiler instead of ELP?
>
> - M-x profiler-start RET RET
> - ... reproduce the slow operation ...
> - M-x profiler-report RET
> - C-u RET on the first entry to unfold it

Yes. I'll do that in some days, when mapcar becomes slow again.

-- 
           Peter