From owner-freebsd-arch@FreeBSD.ORG  Tue Mar 31 06:50:43 2009
Return-Path: <owner-freebsd-arch@FreeBSD.ORG>
Delivered-To: arch@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id A00CD106566B;
	Tue, 31 Mar 2009 06:50:43 +0000 (UTC)
	(envelope-from luigi@onelab2.iet.unipi.it)
Received: from onelab2.iet.unipi.it (onelab2.iet.unipi.it [131.114.9.129])
	by mx1.freebsd.org (Postfix) with ESMTP id 603648FC12;
	Tue, 31 Mar 2009 06:50:43 +0000 (UTC)
	(envelope-from luigi@onelab2.iet.unipi.it)
Received: by onelab2.iet.unipi.it (Postfix, from userid 275)
	id 263CD730A4; Tue, 31 Mar 2009 08:55:48 +0200 (CEST)
Date: Tue, 31 Mar 2009 08:55:48 +0200
From: Luigi Rizzo <rizzo@iet.unipi.it>
To: Poul-Henning Kamp <phk@phk.freebsd.dk>
Message-ID: <20090331065548.GA3851@onelab2.iet.unipi.it>
References: <20090331064959.GA3516@onelab2.iet.unipi.it>
	<96314.1238481987@critter.freebsd.dk>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <96314.1238481987@critter.freebsd.dk>
User-Agent: Mutt/1.4.2.3i
Cc: Daniel Eischen <deischen@freebsd.org>, FreeBSD Arch <arch@freebsd.org>,
	Tim Kientzle <kientzle@freebsd.org>, Marcel Moolenaar <xcllnt@mac.com>
Subject: Re: On errno
X-BeenThere: freebsd-arch@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Discussion related to FreeBSD architecture <freebsd-arch.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-arch>,
	<mailto:freebsd-arch-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-arch>
List-Post: <mailto:freebsd-arch@freebsd.org>
List-Help: <mailto:freebsd-arch-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-arch>,
	<mailto:freebsd-arch-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 31 Mar 2009 06:50:43 -0000

On Tue, Mar 31, 2009 at 06:46:27AM +0000, Poul-Henning Kamp wrote:
> In message <20090331064959.GA3516@onelab2.iet.unipi.it>, Luigi Rizzo writes:
> 
> >we are probably digressing but printf in glibc has specifiers to
> >indicate which argument you want to use for each format.
> >
> >http://www.gnu.org/software/hello/manual/libc/Output-Conversion-Syntax.html
> >
> >I suppose this takes an extra pass over the format string to collect
> >the proper type info for all arguments, so it is not
> >not a dramatic change in the implementation of *printf.
> 
> Yeah, we have that crap too, and you can see how messy and slow our
> printf became as a result in SVN.

I have never run performance tests of printf, but it woudld be
definitely interesting to figure out how expensive is the parsing
of the format specifiers.

cheers
luigi