lisp/emacs-lisp/benchmark.el

   1 ;;; benchmark.el --- support for benchmarking code  -*- lexical-binding: t -*-
   2
   3 ;; Copyright (C) 2003-2017 Free Software Foundation, Inc.
   4
   5 ;; Author: Dave Love  <fx@gnu.org>
   6 ;; Keywords: lisp, extensions
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software: you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation, either version 3 of the License, or
  13 ;; (at your option) any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  22
  23 ;;; Commentary:
  24
  25 ;; Utilities for timing the execution of forms, including the time
  26 ;; taken for GC.  Note that prior to timing code you may want to
  27 ;; ensure things like:  there has just been a GC, the relevant code is
  28 ;; already loaded (so that there's no overhead from autoloading etc.),
  29 ;; and the code is compiled if appropriate (but see
  30 ;; `benchmark-run-compiled').
  31
  32 ;;; Code:
  33
  34 (defmacro benchmark-elapse (&rest forms)
  35   "Return the time in seconds elapsed for execution of FORMS."
  36   (declare (indent 0) (debug t))
  37   (let ((t1 (make-symbol "t1"))
  38         (t2 (make-symbol "t2")))
  39     `(let (,t1 ,t2)
  40        (setq ,t1 (current-time))
  41        ,@forms
  42        (setq ,t2 (current-time))
  43        (float-time (time-subtract ,t2 ,t1)))))
  44
  45 ;;;###autoload
  46 (defmacro benchmark-run (&optional repetitions &rest forms)
  47   "Time execution of FORMS.
  48 If REPETITIONS is supplied as a number, run forms that many times,
  49 accounting for the overhead of the resulting loop.  Otherwise run
  50 FORMS once.
  51 Return a list of the total elapsed time for execution, the number of
  52 garbage collections that ran, and the time taken by garbage collection.
  53 See also `benchmark-run-compiled'."
  54   (declare (indent 1) (debug t))
  55   (unless (natnump repetitions)
  56     (setq forms (cons repetitions forms)
  57           repetitions 1))
  58   (let ((i (make-symbol "i"))
  59         (gcs (make-symbol "gcs"))
  60         (gc (make-symbol "gc")))
  61     `(let ((,gc gc-elapsed)
  62            (,gcs gcs-done))
  63        (list ,(if (> repetitions 1)
  64                   ;; Take account of the loop overhead.
  65                   `(- (benchmark-elapse (dotimes (,i ,repetitions)
  66                                           ,@forms))
  67                       (benchmark-elapse (dotimes (,i ,repetitions))))
  68                 `(benchmark-elapse ,@forms))
  69              (- gcs-done ,gcs)
  70              (- gc-elapsed ,gc)))))
  71
  72 ;;;###autoload
  73 (defmacro benchmark-run-compiled (&optional repetitions &rest forms)
  74   "Time execution of compiled version of FORMS.
  75 This is like `benchmark-run', but what is timed is a funcall of the
  76 byte code obtained by wrapping FORMS in a `lambda' and compiling the
  77 result.  The overhead of the `lambda's is accounted for."
  78   (declare (indent 1) (debug t))
  79   (unless (natnump repetitions)
  80     (setq forms (cons repetitions forms)
  81           repetitions 1))
  82   (let ((i (make-symbol "i"))
  83         (gcs (make-symbol "gcs"))
  84         (gc (make-symbol "gc"))
  85         (code (byte-compile `(lambda () ,@forms)))
  86         (lambda-code (byte-compile `(lambda ()))))
  87     `(let ((,gc gc-elapsed)
  88            (,gcs gcs-done))
  89        (list ,(if (> repetitions 1)
  90                   ;; Take account of the loop overhead.
  91                   `(- (benchmark-elapse (dotimes (,i ,repetitions)
  92                                           (funcall ,code)))
  93                       (benchmark-elapse (dotimes (,i ,repetitions)
  94                                           (funcall ,lambda-code))))
  95                 `(benchmark-elapse (funcall ,code)))
  96              (- gcs-done ,gcs) (- gc-elapsed ,gc)))))
  97
  98 ;;;###autoload
  99 (defun benchmark (repetitions form)
 100   "Print the time taken for REPETITIONS executions of FORM.
 101 Interactively, REPETITIONS is taken from the prefix arg.
 102 For non-interactive use see also `benchmark-run' and
 103 `benchmark-run-compiled'."
 104   (interactive "p\nxForm: ")
 105   (let ((result (eval `(benchmark-run ,repetitions ,form))))
 106     (if (zerop (nth 1 result))
 107         (message "Elapsed time: %fs" (car result))
 108       (message "Elapsed time: %fs (%fs in %d GCs)" (car result)
 109                (nth 2 result) (nth 1 result)))))
 110
 111 (provide 'benchmark)
 112
 113 ;;; benchmark.el ends here