From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: ludo@gnu.org (Ludovic =?iso-8859-1?Q?Court=E8s?=) Newsgroups: gmane.lisp.guile.devel Subject: Optimizing =?utf-8?b?4oCYc3RyaW5nPeKAmQ==?= Date: Tue, 22 Jun 2010 21:40:15 +0200 Message-ID: <87k4pqj1pc.fsf@gnu.org> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="=-=-=" X-Trace: dough.gmane.org 1277235632 31083 80.91.229.12 (22 Jun 2010 19:40:32 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Tue, 22 Jun 2010 19:40:32 +0000 (UTC) Cc: guile-devel@gnu.org To: Mike Gran Original-X-From: guile-devel-bounces+guile-devel=m.gmane.org@gnu.org Tue Jun 22 21:40:29 2010 Return-path: Envelope-to: guile-devel@m.gmane.org Original-Received: from lists.gnu.org ([199.232.76.165]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1OR9Kd-000202-3W for guile-devel@m.gmane.org; Tue, 22 Jun 2010 21:40:27 +0200 Original-Received: from localhost ([127.0.0.1]:46310 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OR9Kb-0005ge-7g for guile-devel@m.gmane.org; Tue, 22 Jun 2010 15:40:25 -0400 Original-Received: from [140.186.70.92] (port=41269 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1OR9KW-0005gQ-Rb for guile-devel@gnu.org; Tue, 22 Jun 2010 15:40:22 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1OR9KV-0002PD-Kr for guile-devel@gnu.org; Tue, 22 Jun 2010 15:40:20 -0400 Original-Received: from mail3-relais-sop.national.inria.fr ([192.134.164.104]:3034) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1OR9KV-0002Ov-GG for guile-devel@gnu.org; Tue, 22 Jun 2010 15:40:19 -0400 X-IronPort-AV: E=Sophos;i="4.53,461,1272837600"; d="scan'208";a="52910678" Original-Received: from reverse-83.fdn.fr (HELO nixey) ([80.67.176.83]) by mail3-relais-sop.national.inria.fr with ESMTP/TLS/DHE-RSA-AES128-SHA; 22 Jun 2010 21:40:17 +0200 X-URL: http://www.fdn.fr/~lcourtes/ X-Revolutionary-Date: 4 Messidor an 218 de la =?iso-8859-1?Q?R=E9volution?= X-PGP-Key-ID: 0xEA52ECF4 X-PGP-Key: http://www.fdn.fr/~lcourtes/ludovic.asc X-PGP-Fingerprint: 83C4 F8E5 10A3 3B4C 5BEA D15D 77DD 95E2 EA52 ECF4 X-OS: x86_64-unknown-linux-gnu User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.2 (gnu/linux) X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-BeenThere: guile-devel@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Developers list for Guile, the GNU extensibility library" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: guile-devel-bounces+guile-devel=m.gmane.org@gnu.org Errors-To: guile-devel-bounces+guile-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.lisp.guile.devel:10548 Archived-At: --=-=-= Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Hello! While profiling a Scheme program, I noticed that =E2=80=98string=3D?=E2=80= =99 was surprisingly high. I ran OProfile on this Scheme program: --8<---------------cut here---------------start------------->8--- (define s (make-string 123 #\a)) (let loop () (string=3D s s) (loop)) --8<---------------cut here---------------end--------------->8--- The flat profile was like this: --8<---------------cut here---------------start------------->8--- samples % symbol name 13683 24.6367 scm_i_string_ref 13447 24.2118 compare_strings 8652 15.5782 scm_i_string_chars 4801 8.6444 vm_debug_engine 4535 8.1654 scm_i_str2symbol 2123 3.8225 scm_ihashq 1338 2.4091 scm_fluid_ref 993 1.7879 scm_i_string_hash 750 1.3504 scm_hash_fn_get_handle 616 1.1091 scm_module_variable 445 0.8012 scm_from_locale_stringn --8<---------------cut here---------------end--------------->8--- I came up with the following patch, which adds a shortcut for the most common case: --=-=-= Content-Type: text/x-patch Content-Disposition: inline diff --git a/libguile/srfi-13.c b/libguile/srfi-13.c index c4e8571..4803830 100644 --- a/libguile/srfi-13.c +++ b/libguile/srfi-13.c @@ -1,6 +1,6 @@ /* srfi-13.c --- SRFI-13 procedures for Guile * - * Copyright (C) 2001, 2004, 2005, 2006, 2008, 2009 Free Software Foundation, Inc. + * Copyright (C) 2001, 2004, 2005, 2006, 2008, 2009, 2010 Free Software Foundation, Inc. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public License @@ -1168,6 +1168,21 @@ SCM_DEFINE (scm_string_eq, "string=", 2, 4, 0, "value otherwise.") #define FUNC_NAME s_scm_string_eq { + if (SCM_LIKELY (scm_i_is_narrow_string (s1) == scm_i_is_narrow_string (s2) + && SCM_UNBNDP (start1) && SCM_UNBNDP (end1) + && SCM_UNBNDP (start2) && SCM_UNBNDP (end2))) + { + size_t len1, len2; + + len1 = scm_i_string_length (s1); + len2 = scm_i_string_length (s2); + + if (SCM_LIKELY (len1 == len2)) + return scm_from_bool (memcmp (scm_i_string_chars (s1), + scm_i_string_chars (s2), + len1) == 0); + } + return compare_strings (FUNC_NAME, 0, s1, s2, start1, end1, start2, end2, SCM_BOOL_F, SCM_BOOL_F, SCM_BOOL_F, SCM_BOOL_F, SCM_BOOL_T); --=-=-= Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable It=E2=80=99s quite inelegant, but it leads to a more balanced profile: --8<---------------cut here---------------start------------->8--- samples % symbol name 8079 23.3984 scm_string_eq 5649 16.3606 vm_debug_engine 5624 16.2882 scm_i_str2symbol 2840 8.2252 scm_ihashq 1755 5.0828 scm_i_string_hash 1637 4.7411 scm_fluid_ref 1027 2.9744 scm_i_string_ref 1011 2.9281 scm_hash_fn_get_handle 877 2.5400 scm_i_string_chars 793 2.2967 scm_module_variable 553 1.6016 scm_from_locale_stringn 471 1.3641 scm_from_stringn 426 1.2338 scm_sym2var 384 1.1121 scm_i_make_string 317 0.9181 scm_module_lookup --8<---------------cut here---------------end--------------->8--- ... and a 43% execution time improvement on a tight loop that does =E2=80=98string=3D=E2=80=99. OK to commit? Ideas for a better solution? Thanks, Ludo=E2=80=99. --=-=-=--