From owner-freebsd-hackers@FreeBSD.ORG  Fri Jun 27 09:02:20 2008
Return-Path: <owner-freebsd-hackers@FreeBSD.ORG>
Delivered-To: hackers@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id C7A1A1065687
	for <hackers@freebsd.org>; Fri, 27 Jun 2008 09:02:20 +0000 (UTC)
	(envelope-from rdivacky@vlk.vlakno.cz)
Received: from vlakno.cz (vlk.vlakno.cz [62.168.28.247])
	by mx1.freebsd.org (Postfix) with ESMTP id 8E64A8FC16
	for <hackers@freebsd.org>; Fri, 27 Jun 2008 09:02:20 +0000 (UTC)
	(envelope-from rdivacky@vlk.vlakno.cz)
Received: from localhost (localhost [127.0.0.1])
	by vlakno.cz (Postfix) with ESMTP id 747B7681BED
	for <hackers@freebsd.org>; Fri, 27 Jun 2008 10:43:30 +0200 (CEST)
X-Virus-Scanned: amavisd-new at vlakno.cz
Received: from vlakno.cz ([127.0.0.1])
	by localhost (vlk.vlakno.cz [127.0.0.1]) (amavisd-new, port 10024)
	with ESMTP id yaVPjrVVR2J7 for <hackers@freebsd.org>;
	Fri, 27 Jun 2008 10:43:29 +0200 (CEST)
Received: from vlk.vlakno.cz (localhost [127.0.0.1])
	by vlakno.cz (Postfix) with ESMTP id 58E04681858
	for <hackers@freebsd.org>; Fri, 27 Jun 2008 10:43:29 +0200 (CEST)
Received: (from rdivacky@localhost)
	by vlk.vlakno.cz (8.14.2/8.14.2/Submit) id m5R8hTnP039575
	for hackers@freebsd.org; Fri, 27 Jun 2008 10:43:29 +0200 (CEST)
	(envelope-from rdivacky)
Date: Fri, 27 Jun 2008 10:43:29 +0200
From: Roman Divacky <rdivacky@freebsd.org>
To: hackers@freebsd.org
Message-ID: <20080627084328.GA39337@freebsd.org>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
User-Agent: Mutt/1.4.2.3i
Cc: 
Subject: kmem_alloc_wait and memory pools questions
X-BeenThere: freebsd-hackers@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Technical Discussions relating to FreeBSD
	<freebsd-hackers.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>, 
	<mailto:freebsd-hackers-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-hackers>
List-Post: <mailto:freebsd-hackers@freebsd.org>
List-Help: <mailto:freebsd-hackers-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>,
	<mailto:freebsd-hackers-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Fri, 27 Jun 2008 09:02:20 -0000

hi

I have two questions:

1) is kmem_alloc_wait() expensive operation? I believe it's not
very cheap looking at the code but I want confirmation

2) is there a support for memory pools in FreeBSD?

to give you a little background why I am asking this. In NetBSD Andrew Doran
claims that replacing allocation from a memory submap with an allocation
from a memory pool for exec*() args he can speedup exec*() by ~25%

I wonder if this applies to FreeBSD too so I am investigating it a little.

thnx!

roman