220 21870 article Path: news.gmane.org!not-for-mail From: Evgeny Panasyuk Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: is await an extension of the do-notation? (was Re: Re: Resumable expressions p0114r0 vs async/await P0057R0) Date: Sun, 18 Oct 2015 01:52:32 -0700 (PDT) Lines: 188 Approved: news@gmane.org Message-ID: References: <639f0012-8cb4-4db3-82a6-8d042a3497f9@isocpp.org> <1d15dbc4-e0c1-4df1-86db-014e11f14d26@isocpp.org> <56114953.4030701@wanadoo.fr> <561B403D.4030403@gmail.com> <561C07D1.3080304@gmail.com> <561C213F.1060009@gmail.com> <561C3875.2050701@gmail.com> <86924069-44d0-447f-bf8a-a42e46579832@isocpp.org> <561D79A7.8080007@gmail.com> <894616d6-9609-4038-b2bc-d2c62df21e0f@isocpp.org> <99bdb3ae-9214-4440-8572-4c47a61eda46@isocpp.org> <58628096-14ae-42b2-89d3-c0bd2183bbc0@isocpp.org> <561DC957.8080603@gmail.com> <510ce172-976a-4e3a-ae68-31fdb40af4d7@isocpp.org> <9dd3f28c-4ffb-4e08-9955-242c46e14527@isocpp.org> <31d5f64f-8db9-4ba3-aca7-872114b9776d@isocpp.org> <561DE488.3040103@gmail.com> <5587a3fd-499c-42b3-bf05-fd5cdc2d9118@isocpp.org> <561EF19E.6010405@gmail.com> <7560dfa8-c77f-41ec-9c0d-c88fe65e20b5@isocpp.org> Reply-To: std-proposals@isocpp.org NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_898_198255041.1445158353080" X-Trace: ger.gmane.org 1445158362 1728 80.91.229.3 (18 Oct 2015 08:52:42 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sun, 18 Oct 2015 08:52:42 +0000 (UTC) To: ISO C++ Standard - Future Proposals Original-X-From: std-proposals+bncBC54TLGKR4LBBUV3RWYQKGQEMX6GCFI@isocpp.org Sun Oct 18 10:52:42 2015 Return-path: Envelope-to: gclcip-std-proposals@m.gmane.org Original-Received: from mail-io0-f197.google.com ([209.85.223.197]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Znjhp-0003Cy-5f for gclcip-std-proposals@m.gmane.org; Sun, 18 Oct 2015 10:52:41 +0200 Original-Received: by iow1 with SMTP id 1sf172236265iow.1 for ; Sun, 18 Oct 2015 01:52:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:message-id:in-reply-to:references:subject:mime-version :content-type: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=VUaHfqMUoxeb6EkHNYO+0RWoFTQG2rzN9Q7XnFMxIdY=; b=EHKu5bke2/L/ZSWrMXg2h2YikKN2J1YLgnKXbeF7ccnGB4f8flKm71gxlvhLkJsCu3 FHFifiwc8sV0/+fO9DentcvT0LSV7hltrmiCg5SqbtwhAd+uLMLQPOfcYEmNdTVyXwsC 9gZ8xfItWCrfl9zHYcXnMdqyqyE/zvpOwqBckrZL0GDXZnfLfM/YkuNJNw9Zk7Xk2D8q oFZA1CcUMWCAtk4/xg09ar7paR1/leFtA1zmILovfT1VTkhXMeq2DIGgTQWri0M6Q+ZJ 3mou7kXkQ1+vAhstjbG6t+nSg8BSzOpff4i78gQY256JYD9u2OmD0GMywAJRE/pBHLqc LnJw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:message-id:in-reply-to:references :subject:mime-version:content-type: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=VUaHfqMUoxeb6EkHNYO+0RWoFTQG2rzN9Q7XnFMxIdY=; b=NsWMzX0KmVH0ZOG4hkzSJtdTkoCm8KZssjGe10U9vt0RXhY2qZ8MVWc08OtEHonQYM 7c+KIY4MPZELtfQIbOFmyIkyRnYDKnby4BTk0M1lPLQOhWVUK9T98fsJtCV33n/ughB3 XuVjvBnFcq4MNIt4jA6va1+4AB+E0FgJMaQzD6FIkW3kOLGeRME5RIGl6MXV4lNVusjC RaBGpQl79WPKt/ZGoU2qCWHcH9FUhIna89XbqWPLdiKbs+goWe8HVnGlWBWJHLox9uUq PaTzknbK2GbH2juCv6YI2c6lrlH9tvsmRuqnWxUWn1HVv3GZl8UZH0gamNc3BtMGUk2W I8Lw== X-Gm-Message-State: ALoCoQn7qOUqF/eSeuPmeB5zFrkM1YwPaPv6Th5R9D61CcGYQOsZIi5u/1R/EYvWuCPuHvxQebWg X-Received: by 10.107.162.142 with SMTP id l136mr20891531ioe.32.1445158355076; Sun, 18 Oct 2015 01:52:35 -0700 (PDT) X-BeenThere: std-proposals@isocpp.org Original-Received: by 10.107.169.66 with SMTP id s63ls755318ioe.68.gmail; Sun, 18 Oct 2015 01:52:34 -0700 (PDT) X-Received: by 10.50.225.70 with SMTP id ri6mr267106igc.9.1445158354371; Sun, 18 Oct 2015 01:52:34 -0700 (PDT) In-Reply-To: X-Original-Sender: Evgeny.Panasyuk@gmail.com Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Spam-Checked-In-Group: std-proposals@isocpp.org 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:21870 Archived-At: ------=_Part_898_198255041.1445158353080 Content-Type: multipart/alternative; boundary="----=_Part_899_96203393.1445158353081" ------=_Part_899_96203393.1445158353081 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable 18 October 2015 =D0=B3., 11:07:55 UTC+3 TONGARI J: > > > Out of curiosity, what does the corresponding macro version look like? > It is very similar in structure: COROUTINE(int, yield_demo, (int, N), (int, i)) { for (i =3D 0; i !=3D N; ++i) YIELD i; return; } COROUTINE_END Due limitation of macro-implementation major difference here is that you=20 have to put all locals (loop variable i) at the top, like in old C or=20 Pascal. =20 > do you provide the similar iterator API and use it for comparison? > Yes, I used very similar input iterator to one defined int=20 std::experimental::generator, and used range-based-for (and actually *main*= =20 is exactly same). But if use coroutine directly, without iterators and range-based-for (which= =20 are not well suited for input ranges), then GCC generates following code=20 within loop: ..L5: addl $1, %ebx cmpl $1073741824, %ebx jne .L6 ... branch with ret ... ..L6: .cfi_restore_state movl %ebx, %edi call _Z5printi jmp .L5 It is almost zero overhead. Small issue here is that looks like it does not= =20 understand which branch is more likely, that's why there is "split" of code= =20 and unconditional jump to .L5. Anyway, I do realize that I should provide full code, more results data,=20 etc, make other tests, add await, etc. That's why I said that detailed=20 report is required. --=20 ---=20 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 e= mail to std-proposals+unsubscribe@isocpp.org. To post to this group, send email to std-proposals@isocpp.org. Visit this group at http://groups.google.com/a/isocpp.org/group/std-proposa= ls/. ------=_Part_899_96203393.1445158353081 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
18 October 2015 =D0=B3., 11:07:55 UTC+3 TONGARI J:

Out of curiosity, what does the correspondin= g macro version look like?

It = is very similar in structure:
COROUTINE(int, yiel= d_demo, (int, N),
=C2=A0 =C2=A0 (int, i))
{
=C2=A0 =C2=A0 for (i =3D = 0;<= span style=3D"color: #000;" class=3D"styled-by-prettify"> i !=3D N; ++i)
=C2= =A0 =C2=A0 =C2=A0 =C2=A0 YIELD i;
=C2=A0 =C2=A0 return;
}
= COROUTINE_END
Due limitation of macro-implementati= on major difference here is that you have to put all locals (loop variable = i) at the top, like in old C or Pascal.
=C2=A0
<= div>do you provide the similar iterator API and use it for comparison?

Yes, I used very similar input ite= rator to one defined int std::experimental::generator, and used range-based= -for (and actually main is exactly same).

But if use coroutin= e directly, without iterators and range-based-for (which are not well suite= d for input ranges), then GCC generates following code within loop:
=
..L5:
	addl	$1, %ebx
	cmpl	$1073741824, %ebx<=
/pre>
	jne	.L6
=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 ... branch with r= et ...
.L6:
	.cfi_restore_state
	movl	=
%ebx, %edi
	call	_Z5printi
	jmp	.L5

It is almost zero overhead. Small issue here is that looks like it do= es not understand which branch is more likely, that's why there is &quo= t;split" of code and unconditional jump to .L5.

Anyway, I do re= alize that I should provide full code, more results data, etc, make other t= ests, add await, etc. That's why I said that detailed report is require= d.

--

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To unsubscribe from this group and stop receiving emails from it, send an e= mail to std-proposa= ls+unsubscribe@isocpp.org.
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Visit this group at http://groups.google.com/a/isocpp.org/group/std-proposals/<= /a>.
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