Add Performance section.

1 files changed, 24 insertions, 0 deletions

diff --git a/init.org b/init.org
index 46783a5..23f53c3 100644
--- a/init.org
+++ b/init.org
@@ -29,6 +29,30 @@ We take all code blocks in this file and assemble an =init.el= from it if the so
       (load target))))
 #+END_SRC
 
+* Performance
+
+Make startup faster by reducing the frequency of garbage collection and then use a hook to measure Emacs startup time.
+
+#+begin_src elisp
+;; The default is 800 kilobytes.  Measured in bytes.
+(setq gc-cons-threshold (* 50 1000 1000))
+
+;; Profile emacs startup
+(add-hook 'emacs-startup-hook
+          (lambda ()
+            (message "*** Emacs loaded in %s with %d garbage collections."
+                     (format "%.2f seconds"
+                             (float-time
+                              (time-subtract after-init-time before-init-time)))
+                     gcs-done)))
+#+end_src
+
+Native compilation gives Emacs a speed boost, but it spews compiler warnings that are quite annoying.  Silence them.
+
+#+begin_src elisp
+(setq comp-async-report-warnings-errors nil)
+#+end_src
+
 * Initialise packages
 
 Emacs is an operating system and I use it as such (see [[http://elephly.net/posts/2016-02-14-ilovefs-emacs.html][this blog post]]).  I rely on quite a few extensions that have been made available on various ELPA repositories.  Recently, I have moved to installing and managing Emacs packages like any other software package on my system with the functional package manager [[https://gnu.org/s/guix][GNU Guix]].  I find this more reliable, although at first it is slightly less convenient as I can no longer just use =package.el= but first need to package the Elisp code for Guix.