X-Recipient:	archive-cygwin AT delorie DOT com
X-SWARE-Spam-Status:	No, hits=-2.2 required=5.0 tests=AWL,BAYES_00,DKIM_SIGNED,DKIM_VALID,RCVD_IN_DNSWL_LOW
X-Spam-Check-By:	sourceware.org
Message-ID:	<4E7FCC4C.4090609@cwilson.fastmail.fm>
Date:	Sun, 25 Sep 2011 20:50:20 -0400
From:	Charles Wilson <cygwin AT cwilson DOT fastmail DOT fm>
User-Agent:	Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.8.1.23) Gecko/20090812 Thunderbird/2.0.0.23 Mnenhy/0.7.6.666
MIME-Version:	1.0
To:	Cygwin Mailing List <cygwin AT cygwin DOT com>, bug-gnulib AT gnu DOT org
Subject:	Re: Relocation patch for cygwin
References:	<4D430530 DOT 7050401 AT cwilson DOT fastmail DOT fm> <j5ip1t$qhd$1 AT dough DOT gmane DOT org>
In-Reply-To:	<j5ip1t$qhd$1@dough.gmane.org>
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

On 9/23/2011 4:10 PM, jojelino wrote:
> It fixed the relocation problem. but led performance issue :(
> 
> $ time id > /dev/null
> 
> real    0m0.141s
> user    0m0.000s
> sys     0m0.000s

Well, the libiconv distributed as an official cygwin package *SHOULD*
not have been built with --enable-relocation, so only a subset of the
"relocation" code *OUGHT* to be involved -- just enough for any calls to
relocate() to return the passed-in string IIRC.

However...it appears that I MAY have mistakenly uploaded the version I
built WITH relocation enabled (which I generally do for testing
purposes, just to make sure it still works).  I'll need to double check.

> The attached is report gprof produced when invoked *id* . as you can
> see, format_process_maps consumes 70% of the lifetime(0.5s with
> profiling overhead). this is reproducible whenever we do
> open('/proc/self/maps').
> the problem is, the cost is too expensive. gnulib should care about
> cygwin do sacrifice performance for compatibility.

I'll double check both libiconv/iconv, and libintl/gettext -- but my
initial suspicions are that only libiconv/iconv was accidentally build
with relocation enabled.

> As a workaround, how about rebuild libintl without capacity of relocatable?
> because in cygwin libintl is expected to place in /bin so there's no use
> of relocatable.

Right, and it is intended that, in the cygwin official packages, both
libiconv and libintl are built without relocation support.  If that
isn't true, it's a (cygwin packaging) bug.

I have no opinion on whether perceived slowness in the relocation code
itself, or in cygwin code called BY the relocation code such as
format_process_maps, constitutes a bug either in cygwin or gnulib.

--
Chuck

--
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

- Raw text -