From 4bba7122f3eec6370add26fdf37ab2c838121509 Mon Sep 17 00:00:00 2001
From: Nikolai Shields <nshields@dwavesys.com>
Date: Mon, 21 Oct 2024 23:53:50 -0500
Subject: [PATCH] Add performance optimizations

- monitoring startup and gc times
- IO, file ops, and rendering
---
 config.org | 125 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 123 insertions(+), 2 deletions(-)

diff --git a/config.org b/config.org
index 156f080..5ea6cd9 100644
--- a/config.org
+++ b/config.org
@@ -26,8 +26,6 @@ This configuration needs to be loaded by =init.el=. Create an =init.el= with thi
 Early-init optimizations for faster Emacs startup.
 
 #+begin_src emacs-lisp
-;; Garbage collection
-(setq gc-cons-threshold 100000000)           ; 100mb
 (setq read-process-output-max (* 1024 1024)) ; 1mb
 
 ;; Faster startup
@@ -35,6 +33,129 @@ Early-init optimizations for faster Emacs startup.
 (setq site-run-file nil)
 #+end_src
 
+** Garbage Collection
+The garbage collector in Emacs can significantly impact performance. We can optimize it in several ways:
+
+#+begin_src emacs-lisp
+;; Increase garbage collection threshold
+;; Default is 800 kilobytes
+(setq gc-cons-threshold 100000000)         ; 100mb during initialization
+(setq gc-cons-percentage 0.6)              ; Default is 0.1
+
+;; Reset garbage collection after initialization
+(add-hook 'emacs-startup-hook
+          (lambda ()
+            (setq gc-cons-threshold 16777216    ; 16mb
+                  gc-cons-percentage 0.1)))
+
+;; Collect garbage when Emacs is out of focus
+(add-function :after after-focus-change-function
+  (lambda ()
+    (unless (frame-focus-state)
+      (garbage-collect))))
+#+end_src
+
+** File Processing
+Optimize how Emacs handles file operations and processes:
+
+#+begin_src emacs-lisp
+;; Increase amount of data read from processes
+(setq read-process-output-max (* 1024 1024)) ; 1mb
+
+;; File name handler optimization
+(defvar default-file-name-handler-alist file-name-handler-alist)
+(setq file-name-handler-alist nil)          ; Remove handlers during startup
+
+;; Restore file name handlers after initialization
+(add-hook 'emacs-startup-hook
+          (lambda ()
+            (setq file-name-handler-alist default-file-name-handler-alist)))
+#+end_src
+
+** Startup Optimizations
+Disable unnecessary features during startup:
+
+#+begin_src emacs-lisp
+;; Faster startup
+(setq package-enable-at-startup nil)          ; Don't load packages at startup
+(setq site-run-file nil)                     ; Don't load site-wide runtime config
+(setq frame-inhibit-implied-resize t)         ; Don't resize frame during init
+
+;; Disable UI elements early
+(push '(menu-bar-lines . 0) default-frame-alist)
+(push '(tool-bar-lines . 0) default-frame-alist)
+(push '(vertical-scroll-bars) default-frame-alist)
+
+;; Disable bidirectional text scanning for small performance boost
+(setq-default bidi-paragraph-direction 'left-to-right)
+(setq bidi-inhibit-bpa t)
+#+end_src
+
+** Font Performance
+Optimize font rendering:
+#+begin_src emacs-lisp
+;; Prevent font cache compaction during GC for potentially better performance
+;; at the cost of higher memory usage
+(setq inhibit-compacting-font-caches t)
+;; Font rendering optimization
+(setq use-default-font-for-symbols nil)
+(when (functionp 'harfbuzz-font)
+  (setq harfbuzz-font t))
+
+;; File operation optimization
+(setq find-file-visit-truename nil)  ; Don't resolve symlinks
+(setq vc-follow-symlinks nil)        ; Don't follow symlinks in version control
+#+end_src
+
+** IO Performance
+Optimize file system operations:
+
+#+begin_src emacs-lisp
+;; Lock files (handle with care)
+(setq create-lockfiles nil)                      ; Disable lock files completely
+;; OR for more granular control:
+(setq lock-file-name-transforms                  ; Store lock files elsewhere
+      `((".*" ,(concat user-emacs-directory "locks/") t)))
+
+;; Backup settings (safer alternative to disabling)
+(setq backup-directory-alist                     ; Store backups in separate directory
+      `(("." . ,(concat user-emacs-directory "backups"))))
+(setq backup-by-copying t)                       ; Always copy, don't rename
+(setq delete-old-versions t)                     ; Clean up old backups
+(setq kept-new-versions 6)                       ; Keep 6 newest versions
+(setq kept-old-versions 2)                       ; Keep 2 oldest versions
+
+;; Auto-save optimization
+(setq auto-save-list-file-prefix nil)           ; Disable auto-save list
+(setq auto-save-default t)                      ; Keep auto-save itself enabled
+(setq auto-save-interval 1000)                  ; Increase operations between auto-saves
+(setq auto-save-timeout 30)                     ; Increase idle time before auto-save
+
+;; Local variables handling
+(setq enable-local-variables :safe)             ; Only allow safe variables
+(setq enable-dir-local-variables nil)           ; Disable directory locals
+(setq enable-local-eval nil)                    ; Disable local eval for security
+
+;; Display and rendering
+(setq redisplay-skip-fontification-on-input t)  ; Skip fontification during typing
+(setq fast-but-imprecise-scrolling t)          ; Faster scrolling
+(setq jit-lock-defer-time 0.05)                ; Tiny delay for better responsiveness
+
+#+end_src
+** Monitoring Performance
+Tools to help monitor Emacs performance:
+
+#+begin_src emacs-lisp
+;; 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
+
 * Basic UI Configuration
 Remove unnecessary UI elements and set basic preferences.