From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Nix Newsgroups: gmane.emacs.devel Subject: Re: Tooltips GC overhead Date: Mon, 10 Aug 2015 18:05:00 +0100 Message-ID: <8737zrt6pv.fsf@esperi.org.uk> References: <55B7796B.3070005@gmx.at> <55B87E3F.80708@gmx.at> <55B8E367.9020201@cs.ucla.edu> <55B8F3E9.5000707@gmx.at> <833806yld0.fsf@gnu.org> <55B915CE.7070803@gmx.at> <55B94267.5050208@cs.ucla.edu> <55BCA454.6050208@gmx.at> <83egjkv2st.fsf@gnu.org> <83twsfu6b5.fsf@gnu.org> <87io8plwx9.fsf@esperi.org.uk> <8737ztiwrx.fsf@fencepost.gnu.org> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1439226368 5145 80.91.229.3 (10 Aug 2015 17:06:08 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 10 Aug 2015 17:06:08 +0000 (UTC) Cc: rudalics@gmx.at, Eli Zaretskii , eggert@cs.ucla.edu, Stefan Monnier , emacs-devel@gnu.org To: David Kastrup Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Mon Aug 10 19:06:07 2015 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1ZOqWU-00068d-8T for ged-emacs-devel@m.gmane.org; Mon, 10 Aug 2015 19:06:06 +0200 Original-Received: from localhost ([::1]:59495 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZOqWO-00010k-La for ged-emacs-devel@m.gmane.org; Mon, 10 Aug 2015 13:06:00 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:46516) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZOqW3-00010H-Ub for emacs-devel@gnu.org; Mon, 10 Aug 2015 13:05:43 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZOqW2-000191-Jl for emacs-devel@gnu.org; Mon, 10 Aug 2015 13:05:39 -0400 Original-Received: from icebox.esperi.org.uk ([81.187.191.129]:46802 helo=mail.esperi.org.uk) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZOqVv-0000yV-1m; Mon, 10 Aug 2015 13:05:31 -0400 Original-Received: from spindle (nix@spindle.srvr.nix [192.168.14.15]) by mail.esperi.org.uk (8.15.2/8.15.2) with ESMTP id t7AH507F016171; Mon, 10 Aug 2015 18:05:00 +0100 Emacs: if it payed rent for disk space, you'd be rich. In-Reply-To: <8737ztiwrx.fsf@fencepost.gnu.org> (David Kastrup's message of "Sat, 08 Aug 2015 18:13:06 +0200") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.0.50 (gnu/linux) X-DCC-URT-Metrics: spindle 1060; Body=6 Fuz1=6 Fuz2=6 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 81.187.191.129 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 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-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:188692 Archived-At: On 8 Aug 2015, David Kastrup uttered the following: > Stefan Monnier writes: > >>> The cost you're trying to defend against here is a mispredicted branch >> >> No, I assume the branch would be properly predicted since it would >> always take the same path. > > If cons is encountered with high frequency. But of course, if it is > not, why bother in the first place? In that case I have no idea what you're trying to defend against. The cost of a single conditional and predicted branch is drowned in the overhead of the allocation that cons has to do anyway. I'd be astonished if you could ever see any performance impact whatsoever. -- NULL && (void)