;;; vlf-tune.el --- VLF tuning operations -*- lexical-binding: t -*- ;; Copyright (C) 2014 Free Software Foundation, Inc. ;; Keywords: large files, batch size, performance ;; Author: Andrey Kotlarski <m00naticus@gmail.com> ;; URL: https://github.com/m00natic/vlfi ;; This file 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, or (at your option) ;; any later version. ;; This file 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; see the file COPYING. If not, write to ;; the Free Software Foundation, Inc., 59 Temple Place - Suite 330, ;; Boston, MA 02111-1307, USA. ;;; Commentary: ;; This package provides wrappers for basic chunk operations that add ;; time statistics and automatic tuning of `vlf-batch-size' for ;; optimal performance. ;;; Code: (defcustom vlf-tune-enabled t "Whether to allow automatic change of batch size. If nil, completely disable. If `stats', maintain measure statistics, but don't change batch size. If t, measure and change." :group 'vlf :type '(choice (const :tag "Enabled" t) (const :tag "Just statistics" stats) (const :tag "Disabled" nil))) (defun vlf-tune-ram-size () "Try to determine RAM size in bytes." (let* ((free-output (shell-command-to-string "free")) (match-from (string-match "[[:digit:]]+" free-output))) (if match-from (* 1000 (string-to-number (substring free-output match-from (match-end 0))))))) (defcustom vlf-tune-max (let ((ram-size (vlf-tune-ram-size))) (if ram-size (/ ram-size 20) large-file-warning-threshold)) "Maximum batch size in bytes when auto tuning." :group 'vlf :type 'integer) (defcustom vlf-tune-step (/ vlf-tune-max 1000) "Step used for tuning in bytes." :group 'vlf :type 'integer) (defvar vlf-tune-insert-bps nil "Vector of bytes per second insert measurements.") (make-variable-buffer-local 'vlf-tune-insert-bps) (put 'vlf-batch-size 'permanent-local t) (defvar vlf-tune-insert-raw-bps nil "Vector of bytes per second non-decode insert measurements.") (make-variable-buffer-local 'vlf-tune-insert-raw-bps) (put 'vlf-tune-insert-raw-bps 'permanent-local t) (defvar vlf-tune-encode-bps nil "Vector of bytes per second encode measurements.") (make-variable-buffer-local 'vlf-tune-encode-bps) (put 'vlf-tune-encode-bps 'permanent-local t) (defvar vlf-tune-write-bps nil "Vector of bytes per second write measurements.") (make-variable-buffer-local 'vlf-tune-write-bps) (put 'vlf-tune-write-bps 'permanent-local t) (defvar vlf-tune-hexl-bps nil "Vector of bytes per second hexlify measurements.") (make-variable-buffer-local 'vlf-tune-hexl-bps) (put 'vlf-tune-hexl-bps 'permanent-local t) (defvar vlf-tune-dehexlify-bps nil "Vector of bytes per second dehexlify measurements.") (make-variable-buffer-local 'vlf-tune-dehexlify-bps) (put 'vlf-tune-dehexlify-bps 'permanent-local t) (defun vlf-tune-initialize-measurement () "Initialize measurement vector." (make-vector (1- (/ vlf-tune-max vlf-tune-step)) '(0 . 0))) (defmacro vlf-tune-add-measurement (vec size time) "Add at an appropriate position in VEC new SIZE TIME measurement. VEC is a vector of (mean time . count) elements ordered by size." `(when vlf-tune-enabled (or ,vec (setq ,vec (vlf-tune-initialize-measurement))) (let* ((idx (max 0 (1- (min (round ,size vlf-tune-step) ;closest index (/ vlf-tune-max vlf-tune-step))))) (existing (aref ,vec idx))) (aset ,vec idx (let ((count (1+ (cdr existing)))) ;recalculate mean (cons (/ (+ (* (1- count) (car existing)) (/ ,size ,time)) count) count)))))) (defmacro vlf-time (&rest body) "Get timing consed with result of BODY execution." `(let ((time (float-time)) (result (progn ,@body))) (cons (- (float-time) time) result))) (defun vlf-tune-insert-file-contents (start end) "Extract decoded file bytes START to END and save time it takes." (let ((result (vlf-time (insert-file-contents buffer-file-name nil start end)))) (vlf-tune-add-measurement vlf-tune-insert-bps (- end start) (car result)) (cdr result))) (defun vlf-tune-insert-file-contents-literally (start end) "Insert raw file bytes START to END and save time it takes." (let ((result (vlf-time (insert-file-contents-literally buffer-file-name nil start end)))) (vlf-tune-add-measurement vlf-tune-insert-raw-bps (- end start) (car result)) (cdr result))) (defun vlf-tune-encode-length (start end) "Get length of encoded region START to END and save time it takes." (let ((result (vlf-time (length (encode-coding-region start end buffer-file-coding-system t))))) (vlf-tune-add-measurement vlf-tune-encode-bps (- end start) (car result)) (cdr result))) (defun vlf-tune-write (start end append visit size) "Save buffer and save time it takes. START, END, APPEND, VISIT have same meaning as in `write-region'. SIZE is number of bytes that are saved." (let ((time (car (write-region start end buffer-file-name append visit)))) (vlf-tune-add-measurement vlf-tune-write-bps size time))) (defun vlf-tune-hexlify () "Activate `hexl-mode' and save time it takes." (let ((time (car (vlf-time (hexl-mode))))) (vlf-tune-add-measurement vlf-tune-hexl-bps hexl-max-address time))) (defun vlf-tune-dehexlify () "Exit `hexl-mode' and save time it takes." (let ((time (car (vlf-time (hexl-mode-exit))))) (vlf-tune-add-measurement vlf-tune-dehexlify-bps hexl-max-address time))) (provide 'vlf-tune) ;;; vlf-tune.el ends here