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

From: Stefan Monnier <[email-masked]>
Date: Mon, 22 Sep 2014 08:49:08 -0400

> ELP shows, that the mapcar function called from gnus-thread-latest-date
> takes a lot of time (uptime of emacs is several days):

This is the wrong measurement: it just means that some calls to mapcar
spend a lot of time in the corresponding loop, but 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.

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

        Stefan