220 34900 <7e04a500-ba3a-432a-a844-7d4def1fb739@isocpp.org> article Path: news.gmane.org!.POSTED!not-for-mail From: euloanty@live.com Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Thoughts on more methods towards containers in the future Date: Sat, 14 Oct 2017 07:02:52 -0700 (PDT) Lines: 167 Approved: news@gmane.org Message-ID: <7e04a500-ba3a-432a-a844-7d4def1fb739@isocpp.org> References: <973f04da-1354-44f4-9d1f-23f04596b8dc@isocpp.org> <20171014085305.GA24512@fukushima.lysator.liu.se> <79c51b8c-6cc2-4872-8651-9dae513d1e21@isocpp.org> <1550fc17-cf97-438d-9e7a-862f729adbf5@isocpp.org> <0cc942cf-a217-4175-98b0-b466ac224dc7@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_14297_812172901.1507989772295" X-Trace: blaine.gmane.org 1507989777 32258 195.159.176.226 (14 Oct 2017 14:02:57 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sat, 14 Oct 2017 14:02:57 +0000 (UTC) Cc: euloanty@live.com To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBDPYX6PYRQNBBDFSRDHQKGQEYLWDQHY@isocpp.org Sat Oct 14 16:02:52 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ua0-f197.google.com ([209.85.217.197]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1e3N1a-0006w7-0f for gclcip-std-proposals@m.gmane.org; Sat, 14 Oct 2017 16:02:46 +0200 Original-Received: by mail-ua0-f197.google.com with SMTP id u32sf5119525uau.22 for ; Sat, 14 Oct 2017 07:02:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isocpp-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:message-id:in-reply-to:references:subject :mime-version:x-original-sender:reply-to:precedence:mailing-list :list-id:list-post:list-help:list-archive:list-subscribe :list-unsubscribe; bh=lvKYcNtw3LXU2LqbklEMO2Fr0bn9q0R+hCJZjz448Rg=; b=LZGO+tXBT5O0L/EjVHRmxwI25bDn0oJwHbLywqAxWZd11vM8NUp2zs+abCytHeZg2R k6z4cyG/Brb//3xGXHSewPCJOwc2DLejtbIUFncng6RAL05EJ+QxE5Cn5C7I4iqvARLw nThv8fmMaQv6inix/caFyp03K0EUGvfFapcN14dkR2iGQAG4a/QZd/WM7/VrYeKJmCsM 6+3mxeBKHmq/6Y6RMbyqTvFNWqvnpSG3xEQN17F3HoOqWDGCci5ypxi8D6Vg8g9y1yyY vWaGbFIElEf5TtQ5LZSKMnmIXYDhEDv/AW9a9sKmOb9m7PI4O/kc+YfwMVFCZhnNgG73 WZCw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:message-id:in-reply-to :references:subject:mime-version:x-original-sender:reply-to :precedence:mailing-list:list-id:x-spam-checked-in-group:list-post :list-help:list-archive:list-subscribe:list-unsubscribe; bh=lvKYcNtw3LXU2LqbklEMO2Fr0bn9q0R+hCJZjz448Rg=; b=gOWRn9BOIMJMMQiQ10dIUZplamw7TrWLyAqUKM4ENOqMPlOD3u7Z4oEESa7++SX94l rncSaKJucNK7RaRKrm/S3WKysXBW8OaP3AqdzQLE8luSeyOq7yzKeINo3j+nP43kCcR2 cn2z/Jr8EEVYwnfCJBrbuB5ICKsiGDYtyZTE6bTOc/hoZ8aQdAElxtZZy6ZP+LGaXwVs 39LtAcZw3crofLZTaBOpMuR4OucAU6MxAmllp4lCCpmb1kz6rJSM0uIh6CcdbhfXvws6 dmg6rPJbUHClud77nUfv6GEoBJmye0G3W4qy6wxDPpVko27VWwV8wLVTmanlCVtXruEI yJJw== X-Gm-Message-State: AMCzsaUYVppAmqqdg369jX5ZwwW9cl3/1kYFvqvobpeD2fnoStHBM74R CULLjojZvvvUDq4dkHySB6fDEA== X-Google-Smtp-Source: AOwi7QCwrlx3eQCZfD0s6HmFKXZW9dBtGp03A84lAmwGUcEft2jOe9v+QK7hgK4TFYdJalNMgAPIRA== X-Received: by 10.159.40.42 with SMTP id c39mr2450926uac.118.1507989773470; Sat, 14 Oct 2017 07:02:53 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.176.13.143 with SMTP id i15ls2644717uak.1.gmail; Sat, 14 Oct 2017 07:02:52 -0700 (PDT) X-Received: by 10.31.160.207 with SMTP id j198mr289345vke.10.1507989772791; Sat, 14 Oct 2017 07:02:52 -0700 (PDT) In-Reply-To: X-Original-Sender: euloanty@live.com Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:34900 Archived-At: ------=_Part_14297_812172901.1507989772295 Content-Type: multipart/alternative; boundary="----=_Part_14298_323414753.1507989772296" ------=_Part_14298_323414753.1507989772296 Content-Type: text/plain; charset="UTF-8" how about adding if check for []? On Saturday, October 14, 2017 at 10:02:28 AM UTC-4, eulo...@live.com wrote: > > reserve is also 1% > > On Saturday, October 14, 2017 at 9:49:14 AM UTC-4, Marcin Jaczewski wrote: >> >> >> >> On Saturday, October 14, 2017 at 3:27:44 PM UTC+2, ejsvifq mabmip wrote: >>> >>> https://github.com/euloanty/cqwrteur-vector/blob/master/deque.cc >>> >>> Try this code. >>> >>> BTW. deque is "slower" than vector because of this dumb check if >>> >>> On Saturday, October 14, 2017 at 9:24:37 AM UTC-4, eulo...@live.com >>> wrote: >>> >>>> O2 wont eliminate this cost. It is not optimization issue. I always use >>>> -O2 to compile my programs >>>> >>>> On Saturday, October 14, 2017 at 9:18:56 AM UTC-4, Todd Fleming wrote: >>>>> >>>>> On Saturday, October 14, 2017 at 8:45:29 AM UTC-4, ejsvifq mabmip >>>>> wrote: >>>>>> >>>>>> On Saturday, October 14, 2017 at 4:53:10 AM UTC-4, Magnus Fromreide >>>>>> wrote: >>>>>>> >>>>>>> On Fri, Oct 13, 2017 at 07:38:20PM -0700, eulo...@live.com wrote: >>>>>>> > Contiguous Containers: >>>>>>> > >>>>>>> > vector: >>>>>>> > add non check push_back. non check resize etc. >>>>>>> >>>>>>> What does this mean, you are a bit thin on details here. >>>>>>> >>>>>>> ok. when you push_back an element into the vector, it will first >>>>>> check whether size()==capacity(). It is an overhead when you know what >>>>>> exactly the size of elements you need. >>>>>> >>>>>> For example: >>>>>> >>>>>> vector v; >>>>>> v.reserve(10000000); >>>>>> for(std::size_t i(0);I!=v.capacity();++i) >>>>>> v.emplace_back(i); >>>>>> >>>>>> will be slower than >>>>>> >>>>>> vector v; >>>>>> v.reserve(10000000); >>>>>> for(std::size_t i(0);I!=v.capacity();++i) >>>>>> v.nonchecked_emplace_back(i); >>>>>> >>>>> >>>>> Benchmark requested using -O2 or higher; I doubt your performance >>>>> claim. >>>>> >>>>> Todd >>>>> >>>>> >> IMHO if check in `emplace_back` cost is too much for you, you probably >> create your own container of use some specialized one from SG14. >> Vector cover 99% use cases, you are probably in 1% that is not included. >> > -- You received this message because you are subscribed to the Google Groups "ISO C++ Standard - Future Proposals" group. 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how about adding if check for []?

On Saturday, Octo= ber 14, 2017 at 10:02:28 AM UTC-4, eulo...@live.com wrote:
reserve is also 1%

On S= aturday, October 14, 2017 at 9:49:14 AM UTC-4, Marcin Jaczewski wrote:


On Saturday, Oc= tober 14, 2017 at 3:27:44 PM UTC+2, ejsvifq mabmip wrote:

Try this code.
BTW. deque is "slower" than vector because of this d= umb check if

On Saturday, October 14, 2017 at 9:24:37 AM UTC-4, e= ulo...@live.com wrote:
O2 wont eliminate this cost. It is not optimization issue. I = always use -O2 to compile my programs

On Saturday, October 14, 2017 = at 9:18:56 AM UTC-4, Todd Fleming wrote:
On Saturday, October 14, 2017 at 8:45:29 AM UTC-4, ej= svifq mabmip wrote:
On Saturday, October 14, 2017 at 4:53:10 AM UTC-4, Magnus Fromreide wrote:=
On Fri, Oct 13, 2017 at 07:38:20PM = -0700, eulo...@live.com wrote:
> Contiguous Containers:
>=20
> vector:
> add non check push_back. non check resize etc.

What does this mean, you are a bit thin on details here.

ok. when you push_back an element into the vector, it= will first check whether size()=3D=3Dcapacity(). It is an overhead when yo= u know what exactly the size of elements you need.

For example:

vector<std::size_t> v;
v.reserve(10000000);
for(std::size_t i(0);I!=3Dv.capacity(= );++i)
=C2=A0 =C2=A0=C2=A0 v.emplace_back(i);

will be slower than

vector<std::size= _t> v;
v.reserve(10000000);
for(std::= size_t i(0);I!=3Dv.capacity();++i)
=C2=A0 =C2=A0=C2=A0 v.noncheck= ed_emplace_back(i);

Bench= mark requested using -O2 or higher; I doubt your performance claim.

Todd

=C2=A0
IMHO if check in `emplace_ba= ck` cost is too much for you, you probably create your own container of use= some specialized one from SG14.
Vector cover 99% use cases, you = are probably in 1% that is not included.
=

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To view this discussion on the web visit https://groups.google.= com/a/isocpp.org/d/msgid/std-proposals/7e04a500-ba3a-432a-a844-7d4def1fb739= %40isocpp.org.
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