[elpa] externals/gcmh 49db303 02/32: initial implementation

[Andrea Corallo]

branch: externals/gcmh
commit 49db3037587b92e1c7e993875d4c609c42df0c36
Author: Andrea Corallo <andrea_corallo@yahoo.it>
Commit: Andrea Corallo <andrea_corallo@yahoo.it>

    initial implementation
---
 gcmh.el | 97 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 97 insertions(+)

diff --git a/gcmh.el b/gcmh.el
index 4500e82..69daea1 100644
--- a/gcmh.el
+++ b/gcmh.el
@@ -1 +1,98 @@
 ;;; gcmh.el --- the Garbage Collector Magic Hack -*- lexical-binding:t -*-
+
+;; Copyright (C) 2019 Andrea Corallo
+
+;; Maintainer: andrea_corallo@yahoo.it
+;; Package: gcmh
+;; Homepage: https://gitlab.com/koral/gcmh
+;; Version: 0.1
+;; Package-Requires:
+;; Keywords: garbage collector, garbage collection
+
+;; This file is not part of GNU Emacs.
+
+;; GNU Emacs is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+;; Enforce an optimized Garbage Collection strategy to minimize GC
+;; interference with the user activity.
+;; A more detailed explanation of the rationale behind this can be found at
+;; http://akrl.sdf.org/
+
+;;; Code:
+
+(defcustom gcmh-low-cons-threshold gc-cons-threshold
+  "High cons gc threshold.
+This is the gc threshold used while in idle.  Default value is \
+`gc-cons-threshold'"
+  :group 'gcmh
+  :type 'number)
+
+(defcustom gcmh-high-cons-threshold #x40000000
+  "High cons gc threshold.
+This should be set to a value that makes GC unlikely but does not make the OS \
+paging."
+  :group 'gcmh
+  :type 'number)
+
+(defcustom gcmh-verbose nil
+  "If t print a message into when garbage collecting."
+  :group 'gcmh
+  :type 'boolean)
+
+(defvar gcmh-timer nil
+  "Idle timer set for trigering GC.")
+
+(defmacro gcmh-time (&rest body)
+  "Measure and return the time it takes to evaluate BODY."
+  `(let ((time (current-time)))
+     ,@body
+     (float-time (time-since time))))
+
+(defun gcmh-set-high-threshold ()
+  "Set the high gc thereshold.
+This is to be used with the `pre-command-hook'."
+  (setq gc-cons-threshold gcmh-high-cons-threshold))
+
+;;;###autoload
+(define-minor-mode gcmh-mode
+  "Minor mode tweak Garbage Colelction strategy."
+  :lighter " GCMH"
+  :global t
+  (cond
+   (gcmh-mode
+    (progn
+      (setq gc-cons-threshold gcmh-high-cons-threshold)
+      ;; Print a message when garbage collecting
+      (setq garbage-collection-messages gcmh-verbose)
+      ;; When idle for 15sec run the GC no matter what.
+      (unless gcmh-timer
+       (setq gcmh-timer
+             (run-with-idle-timer 15 t
+                                  (lambda ()
+                                    (if gcmh-verbose
+                                        (message "Garbage Collector has run 
for %.06fsec"
+                                                 (gcmh-time (garbage-collect)))
+                                      (garbage-collect))
+                                    (setq gc-cons-threshold 
gcmh-low-cons-threshold)))))
+      (add-hook 'pre-command-hook #'gcmh-set-high-threshold)))
+   (t (progn
+       (setq gc-cons-threshold gcmh-low-cons-threshold)
+       (cancel-timer gcmh-timer)
+       (setq gcmh-timer nil)
+       (remove-hook 'pre-command-hook #'gcmh-set-high-threshold)))))
+
+(provide 'gcmh)
+
+;;; gcmh.el ends here