X-Recipient: archive-cygwin AT delorie DOT com
DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id
	:list-unsubscribe:list-subscribe:list-archive:list-post
	:list-help:sender:subject:references:to:from:message-id:date
	:mime-version:in-reply-to:content-type
	:content-transfer-encoding; q=dns; s=default; b=cHhpYF+QPSjA0Hl2
	zjAgQCHv9OXTghmHiYcrraekOC6wd+1ISZp4oxpXauAuks6mwhmESMYwwfTdx9KF
	q77lVpVb0sJjjlGf7z8EhigJlZPzQsNGvgZ6n85wkUmwiIFQLM46IMVC9uRGQ5VX
	2en9YJPZQYgLUYZBYuIc0oAdopU=
DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id
	:list-unsubscribe:list-subscribe:list-archive:list-post
	:list-help:sender:subject:references:to:from:message-id:date
	:mime-version:in-reply-to:content-type
	:content-transfer-encoding; s=default; bh=o2SFVW+M22UnF/EeA02YCX
	XJZL4=; b=hGfddJ/DScHPdYuQBFE308LXMUpGrEnPTKRHtNlf2Nvo/OvKAmHQdP
	WFR7RmWe1Tn6r1fCsEvZTtxqlV5FlCosY8W9wtKItzJs7PneRU0SSiL6cTpBSs8E
	yiCOOwgXV//tO3iVKm0wXtpc/gzhr3ParjlWePcXFhjsZqrm5Z5Zg=
Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm
List-Id: <cygwin.cygwin.com>
List-Subscribe: <mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive: <http://sourceware.org/ml/cygwin/>
List-Post: <mailto:cygwin AT cygwin DOT com>
List-Help: <mailto:cygwin-help AT cygwin DOT com>, <http://sourceware.org/ml/#faqs>
Sender: cygwin-owner AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
Delivered-To: mailing list cygwin AT cygwin DOT com
Authentication-Results: sourceware.org; auth=none
X-Virus-Found: No
X-Spam-SWARE-Status: No, score=-0.1 required=5.0 tests=AWL,BAYES_50,KAM_LAZY_DOMAIN_SECURITY autolearn=no version=3.3.2
X-HELO: m0.truegem.net
Subject: Re: Cygwin multithreading performance
References: <CABPLASTtRK4mNxh0M_AnZgjJQ15kWPx+L=U=VCU3Wwi7jV_57A AT mail DOT gmail DOT com> <564E3017 DOT 90205 AT maxrnd DOT com> <CABPLASTLrH_udLuu2F-m5P6dkENW1Z4YHEudp4NG0-FGLJgPMg AT mail DOT gmail DOT com> <5650379B DOT 4030405 AT maxrnd DOT com> <20151121105301 DOT GE2755 AT calimero DOT vinschen DOT de>
To: cygwin AT cygwin DOT com
From: Mark Geisert <mark AT maxrnd DOT com>
Message-ID: <5652C402.7040006@maxrnd.com>
Date: Sun, 22 Nov 2015 23:45:06 -0800
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:42.0) Gecko/20100101 Firefox/42.0 SeaMonkey/2.39
MIME-Version: 1.0
In-Reply-To: <20151121105301.GE2755@calimero.vinschen.de>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit

Corinna Vinschen wrote:
> On Nov 21 01:21, Mark Geisert wrote:
[...] so I wonder if there's
>> some unintentional serialization going on somewhere, but I don't know yet
>> how I could verify that theory.
>
> If I'm allowed to make an educated guess, the big serializer in Cygwin
> are probably the calls to malloc, calloc, realloc, free.  We desperately
> need a new malloc implementation better suited to multi-threading.

That's very helpful to know.  I'd want to first make sure the heavy lock 
activity I'm seeing in the traces really is due to malloc() and friends 
but I couldn't help a speculative search online for multithread-safe 
malloc().  These turned up:
     tcmalloc - part of google-perftools, requires libunwind, evidently 
not yet ported to Windows AFAICT,
     nedmalloc - http://www.nedprod.com/programs/portable/nedmalloc/
     ptmalloc - http://www.malloc.de/

The latter two are based on Doug Lea's dlmalloc which is also the basis 
of Cygwin's malloc() functions.  As I understand it, ptmalloc in one 
form or another has been part of glibc on Linux for some time.

So there may be a solution in sight if we need to go that direction.  Of 
course, SHTDI as usual :).

..mark

--
Problem reports:       http://cygwin.com/problems.html
FAQ:                   http://cygwin.com/faq/
Documentation:         http://cygwin.com/docs.html
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple