From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Matt Armstrong Newsgroups: gmane.emacs.devel Subject: Re: noverlay branch Date: Thu, 06 Oct 2022 21:11:01 -0700 Message-ID: <87edvki88a.fsf@rfc20.org> References: <1468ca31-1703-82a1-0c8c-be2c5b5674a7@gmail.com> <87r0zld0de.fsf@rfc20.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="9490"; mail-complaints-to="usenet@ciao.gmane.io" Cc: emacs-devel@gnu.org To: Gerd =?utf-8?Q?M=C3=B6llmann?= , Stefan Monnier Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Fri Oct 07 06:12:03 2022 Return-path: Envelope-to: ged-emacs-devel@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1ogeiQ-0002Gn-Mw for ged-emacs-devel@m.gmane-mx.org; Fri, 07 Oct 2022 06:12:03 +0200 Original-Received: from localhost ([::1]:46738 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ogeiP-0005qt-Ae for ged-emacs-devel@m.gmane-mx.org; Fri, 07 Oct 2022 00:12:01 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:32818) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ogehc-0005B1-1p for emacs-devel@gnu.org; Fri, 07 Oct 2022 00:11:12 -0400 Original-Received: from relay6-d.mail.gandi.net ([2001:4b98:dc4:8::226]:43685) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ogehZ-0007jx-CB for emacs-devel@gnu.org; Fri, 07 Oct 2022 00:11:11 -0400 Original-Received: (Authenticated sender: matt@rfc20.org) by mail.gandi.net (Postfix) with ESMTPSA id 2FE9DC0002; Fri, 7 Oct 2022 04:11:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rfc20.org; s=gm1; t=1665115865; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=o86F2d13eiJUEQUIBTcuktENbU5I1mPLEq9BbugrcFo=; b=OIO8ZwEtrddPIvKIr+jMyMsz1pv+juK3ftsSS+hkXCZoit+dtFXRsQpAIjiBes/GcOELNd LeKfavbp3cyCbEyuZ2jurGXmoA1C23jB89Tysil44vwzh8XAKIbdC0OQHTnCe9B8ek1BQk yq4bMyQZdyfCNbOsqOWRsoaSvRggn7rJgbOrUiso/ooRRQ/FV4w3TmXDmIvFV8tnJ2Qnu+ FzI3c9GDGKS/Klai63r3SaOp3vS6cY51byooH83T5e4M8v8D3A3DdfpfEEVEfE2nRxxrNN +9ahmiPoLYmyD4+p2V+ulLXkqo88hGUUSfrio/o/nrBa6m3BPriyfa2BEbzNlg== Original-Received: from matt by naz with local (Exim 4.96) (envelope-from ) id 1ogehR-004Bjw-1v; Thu, 06 Oct 2022 21:11:01 -0700 In-Reply-To: Received-SPF: pass client-ip=2001:4b98:dc4:8::226; envelope-from=matt@rfc20.org; helo=relay6-d.mail.gandi.net X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 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-mx.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.io gmane.emacs.devel:297136 Archived-At: Gerd M=C3=B6llmann writes: > On 22-10-06 6:47 , Matt Armstrong wrote: > >> I see you removed some of the null->parent trick just today. I like >> that idea. It is realtively easy to use actual NULL instead of a >> sentinel NULL in tree algorithms, and I think on modern processors this >> works out for the better. > > Clang libstd++ uses NULL, BTW, and I already wondered a little bit why. I believe GNU libstdc++ does not use sentinel nodes either. I have yet to see see sentinel nodes used in an optimized tree implementation. I think in the context of this overlay work the performance difference is not very significant, since the code is doing a lot of other stuff while traversing the tree.