220 34899 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 07:02:28 -0700 (PDT) Lines: 156 Approved: news@gmane.org Message-ID: 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_14282_107514668.1507989748300" X-Trace: blaine.gmane.org 1507989751 20051 195.159.176.226 (14 Oct 2017 14:02:31 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sat, 14 Oct 2017 14:02:31 +0000 (UTC) Cc: euloanty@live.com To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBDPYX6PYRQNBB5FRRDHQKGQEYYRC7JI@isocpp.org Sat Oct 14 16:02:26 2017 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-ua0-f199.google.com ([209.85.217.199]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1e3N1C-0004As-Pl for gclcip-std-proposals@m.gmane.org; Sat, 14 Oct 2017 16:02:22 +0200 Original-Received: by mail-ua0-f199.google.com with SMTP id s41sf5244767uab.20 for ; Sat, 14 Oct 2017 07:02:30 -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=9551juGAiU9PHQYlHjkKhoL4Xv8kEPSwF0F4R2RQzCA=; b=iELOa4FHbye52JE3clmh542rLlNrS48ItKbsk7KUQ6XaeYsQSNyQquVR+9xb3AWY53 o33sL2EW4Eh/wcLsmYhjlLf5dPBAV7ex3ZLrQgjfffQeU/0xNMfnQVhjiOuAuIvWe8sp HDIEMx0WVh4wFrA4aEO9jaYoIjMGL/8omtc6Dkj4sv7q6FtHwJesgtgxbomCkK/IdsH1 QcAC+E2HIIju+rf5rEtop7ppcH+TPSDsl+1VHNGkNtgorwsfUtoXXY5eV5B6WIuv2uSQ IPTK0OL2Qzg+BrEeH1v98379s84pt51LJxcR1Y26Y12bn2/DsfOs/9dsRSpKxvfYSJFB 24Mg== 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=9551juGAiU9PHQYlHjkKhoL4Xv8kEPSwF0F4R2RQzCA=; b=itJ62vkn49fVpNaqmuESDn2dKi1Q0hMWISdFCTIJxlEnQCugkCOSdkk/Ihf6VVRt50 IomcX2sG26KbmIf5G8togtEGfZElTxylFrJ1YpA0V/ZxttQbX/z/EvQ+MkRhozp8uxdr ahljCNvAPxKXLOQGeR38VANdLR8a5ZHWp+YziUHr4uhaMoP6htVHIOWS8bJWRFA9SfCG x7zCAO8qsZpOvt+Kqr/2JGPNfVs3Cif6NCnGUFoqg+dMQFyFG3xGilw8d1LY34rgqiiQ f3XWv5EhaXaHO2BWdSGYHQi9IuawgL+tEOuz4/oCmR04sR4D/E2i8ZKGro9z3GDb9f+l 2kJA== X-Gm-Message-State: AMCzsaWxvVSrry/pRgiNr7uOpx6rBcFHwTfkrSlxT0JXSKEQQSnvYH9v oXMmi8/dsg/koAvJ9/+gbJQumw== X-Google-Smtp-Source: AOwi7QBN3oKbtqOnMwJO6ECTmsP24tFiRX450JEziNT7Lyfhckw7nKdy3VRC50OBE7gariKVCO4Czg== X-Received: by 10.176.73.105 with SMTP id a38mr2260313uad.60.1507989750170; Sat, 14 Oct 2017 07:02:30 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.31.188.207 with SMTP id m198ls2390183vkf.21.gmail; Sat, 14 Oct 2017 07:02:28 -0700 (PDT) X-Received: by 10.31.95.134 with SMTP id t128mr289245vkb.11.1507989748828; Sat, 14 Oct 2017 07:02:28 -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:34899 Archived-At: ------=_Part_14282_107514668.1507989748300 Content-Type: multipart/alternative; boundary="----=_Part_14283_385819100.1507989748300" ------=_Part_14283_385819100.1507989748300 Content-Type: text/plain; charset="UTF-8" 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. To unsubscribe from this group and stop receiving emails from it, send an email to std-proposals+unsubscribe@isocpp.org. To post to this group, send email to std-proposals@isocpp.org. To view this discussion on the web visit https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/e6b61d03-a64e-48fd-81b5-5a5f937f6d1a%40isocpp.org. ------=_Part_14283_385819100.1507989748300 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
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:

Try this code.

BTW. dequ= e 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 wr= ote:
O2 wont = eliminate this cost. It is not optimization issue. I always use -O2 to comp= ile my programs

On Saturday, October 14, 2017 at 9:18:56 AM UTC-4, T= odd 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:
>=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.

--
You received this message because you are subscribed to the Google Groups &= quot;ISO C++ Standard - Future Proposals" group.
To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposa= ls+unsubscribe@isocpp.org.
To post to this group, send email to std-proposals@isocpp.org.
To view this discussion on the web visit https://groups.google.= com/a/isocpp.org/d/msgid/std-proposals/e6b61d03-a64e-48fd-81b5-5a5f937f6d1a= %40isocpp.org.
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