From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Paul Eggert Newsgroups: gmane.emacs.devel Subject: Re: emacs-26 eec71eb: Speed up replace-buffer-contents Date: Wed, 4 Jul 2018 11:30:12 -0700 Organization: UCLA Computer Science Department Message-ID: References: <20180629135646.6054.66405@vcs0.savannah.gnu.org> <20180629135648.5C95A2053B@vcs0.savannah.gnu.org> <698fc242-71bf-0e6e-5e45-d1be45cbc074@cs.ucla.edu> <837emcjezc.fsf@gnu.org> <517756be-f05e-1fd1-afc9-f8b6d47252f2@cs.ucla.edu> <83va9vohom.fsf@gnu.org> <4705d730-b5a4-efd2-028f-40478b1ac1d5@cs.ucla.edu> <83o9fnnikb.fsf@gnu.org> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Trace: blaine.gmane.org 1530728948 16780 195.159.176.226 (4 Jul 2018 18:29:08 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Wed, 4 Jul 2018 18:29:08 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 Cc: rgm@gnu.org, emacs-devel@gnu.org To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Wed Jul 04 20:29:03 2018 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1famWV-0004Fs-K9 for ged-emacs-devel@m.gmane.org; Wed, 04 Jul 2018 20:29:03 +0200 Original-Received: from localhost ([::1]:48770 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1famYb-0005Js-2R for ged-emacs-devel@m.gmane.org; Wed, 04 Jul 2018 14:31:13 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:43302) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1famXp-0005Jl-WD for emacs-devel@gnu.org; Wed, 04 Jul 2018 14:30:27 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1famXp-0002Gx-1V for emacs-devel@gnu.org; Wed, 04 Jul 2018 14:30:25 -0400 Original-Received: from zimbra.cs.ucla.edu ([131.179.128.68]:34710) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1famXi-0002C6-QV; Wed, 04 Jul 2018 14:30:19 -0400 Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id F357E160668; Wed, 4 Jul 2018 11:30:16 -0700 (PDT) Original-Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id IDnxSB9dfeFM; Wed, 4 Jul 2018 11:30:16 -0700 (PDT) Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 323891606CB; Wed, 4 Jul 2018 11:30:16 -0700 (PDT) X-Virus-Scanned: amavisd-new at zimbra.cs.ucla.edu Original-Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id HjYn-9E-cXai; Wed, 4 Jul 2018 11:30:16 -0700 (PDT) Original-Received: from [192.168.1.9] (unknown [47.154.30.119]) by zimbra.cs.ucla.edu (Postfix) with ESMTPSA id D2979160668; Wed, 4 Jul 2018 11:30:15 -0700 (PDT) Openpgp: preference=signencrypt Autocrypt: addr=eggert@cs.ucla.edu; prefer-encrypt=mutual; keydata= xsFNBEyAcmQBEADAAyH2xoTu7ppG5D3a8FMZEon74dCvc4+q1XA2J2tBy2pwaTqfhpxxdGA9 Jj50UJ3PD4bSUEgN8tLZ0san47l5XTAFLi2456ciSl5m8sKaHlGdt9XmAAtmXqeZVIYX/UFS 96fDzf4xhEmm/y7LbYEPQdUdxu47xA5KhTYp5bltF3WYDz1Ygd7gx07Auwp7iw7eNvnoDTAl KAl8KYDZzbDNCQGEbpY3efZIvPdeI+FWQN4W+kghy+P6au6PrIIhYraeua7XDdb2LS1en3Ss mE3QjqfRqI/A2ue8JMwsvXe/WK38Ezs6x74iTaqI3AFH6ilAhDqpMnd/msSESNFt76DiO1ZK QMr9amVPknjfPmJISqdhgB1DlEdw34sROf6V8mZw0xfqT6PKE46LcFefzs0kbg4GORf8vjG2 Sf1tk5eU8MBiyN/bZ03bKNjNYMpODDQQwuP84kYLkX2wBxxMAhBxwbDVZudzxDZJ1C2VXujC OJVxq2kljBM9ETYuUGqd75AW2LXrLw6+MuIsHFAYAgRr7+KcwDgBAfwhPBYX34nSSiHlmLC+ KaHLeCLF5ZI2vKm3HEeCTtlOg7xZEONgwzL+fdKo+D6SoC8RRxJKs8a3sVfI4t6CnrQzvJbB n6gxdgCu5i29J1QCYrCYvql2UyFPAK+do99/1jOXT4m2836j1wARAQABzSBQYXVsIEVnZ2Vy dCA8ZWdnZXJ0QGNzLnVjbGEuZWR1PsLBfgQTAQIAKAUCTIByZAIbAwUJEswDAAYLCQgHAwIG FQgCCQoLBBYCAwECH In-Reply-To: <83o9fnnikb.fsf@gnu.org> Content-Language: en-US X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] X-Received-From: 131.179.128.68 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:226944 Archived-At: >>> Which particular problem were did you allude to? >> >> Sorry, I've lost context and don't know what this question refers to. >=20 > It refers to this exchange: >=20 >>> I typically measure effectiveness of performance tweaks when using th= e >>> 'configure' default of CFLAGS=3D'-g3 -O2', since that's how it's typi= cally built >>> downstream. If this particular problem is all about CFLAGS=3D-O0 plea= se let me >>> know, as I guess I can look at that too (but would rather not). >=20 >> Which particular problem were did you allude to? >=20 > You said "if this particular problem is about ...", and I asked what > was the particular problem you were talking about. Ah, I meant the particular performance problem that the recent changes ha= ve been=20 trying to alleviate. > It's not rarely_quit that is expensive, it's the few calls to > maybe_quit it does, because maybe_quit accesses two Lisp symbols. I > think. If that's the case, there's still a performance bug in there. The point o= f=20 rarely_quit is to avoid calling maybe_quit in the vast majority of cases.= If=20 maybe_quit is being called so often that it's a performance hog, then it'= s being=20 called too often. By the way, accessing Lisp symbols should not be a serious performance=20 bottleneck. builtin_lisp_symbol takes zero machine instructions unless co= mpiling=20 with -fcheck-pointer-bounds or compiling without optimization. If=20 builtin_lisp_symbol is a serious performance issue when compiling without= =20 optimization (which it shouldn't be), then we need to tune its uses for t= he=20 non-optimized case (though I'd rather avoid that sort of thing, as it is = a=20 throwback to the 1970s to be hand-optimizing to work around lousy compile= rs!).=20 But before resorting to this, I'd first rather understand the maybe_quit = problem=20 mentioned above.