From owner-freebsd-wireless@FreeBSD.ORG  Tue Aug  9 10:28:30 2011
Return-Path: <owner-freebsd-wireless@FreeBSD.ORG>
Delivered-To: freebsd-wireless@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 92949106564A;
	Tue,  9 Aug 2011 10:28:30 +0000 (UTC)
	(envelope-from lev@serebryakov.spb.ru)
Received: from onlyone.friendlyhosting.spb.ru (onlyone.friendlyhosting.spb.ru
	[IPv6:2a01:4f8:131:60a2::2])
	by mx1.freebsd.org (Postfix) with ESMTP id 527878FC18;
	Tue,  9 Aug 2011 10:28:30 +0000 (UTC)
Received: from lion.home.serebryakov.spb.ru (unknown
	[IPv6:2001:470:923f:1:40d5:9d99:be75:3272])
	(Authenticated sender: lev@serebryakov.spb.ru)
	by onlyone.friendlyhosting.spb.ru (Postfix) with ESMTPA id 044454AC1C; 
	Tue,  9 Aug 2011 14:28:27 +0400 (MSD)
Date: Tue, 9 Aug 2011 14:28:25 +0400
From: Lev Serebryakov <lev@serebryakov.spb.ru>
X-Priority: 3 (Normal)
Message-ID: <347137729.20110809142825@serebryakov.spb.ru>
To: Adrian Chadd <adrian@freebsd.org>
In-Reply-To: <CAJ-Vmo=dU0uVeZdhkTsgwb54aHH8AK7eb5FviS3hjgLppSecQg@mail.gmail.com>
References: <1151152206.20110808220720@serebryakov.spb.ru>
	<201108090829.18712.bschmidt@freebsd.org>
	<1681554189.20110809132747@serebryakov.spb.ru>
	<CAJ-VmokAuF6rmN=x1oTE5jksrbf2Psew7-4Qb+Wd-=kZS1svaQ@mail.gmail.com>
	<7764247.20110809135323@serebryakov.spb.ru>
	<CAJ-Vmom-VdzRpS0S7c8z3rH5tYkbk1Nadw-=R6r65OX-_AOX1A@mail.gmail.com>
	<281311475.20110809142033@serebryakov.spb.ru>
	<CAJ-Vmo=dU0uVeZdhkTsgwb54aHH8AK7eb5FviS3hjgLppSecQg@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=koi8-r
Content-Transfer-Encoding: quoted-printable
Cc: freebsd-wireless@freebsd.org
Subject: Re: Bad host-vased AP performace -- and qouple of questions about
	FreeBSD WiFi stack tuning
X-BeenThere: freebsd-wireless@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: "Discussions of 802.11 stack,
	tools device driver development." <freebsd-wireless.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-wireless>, 
	<mailto:freebsd-wireless-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-wireless>
List-Post: <mailto:freebsd-wireless@freebsd.org>
List-Help: <mailto:freebsd-wireless-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-wireless>, 
	<mailto:freebsd-wireless-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 09 Aug 2011 10:28:30 -0000

Hello, Adrian.
You wrote 9 =C1=D7=C7=D5=D3=D4=C1 2011 =C7., 14:21:55:

>>> txpower 15 is actually 15dBm. Ie, try "ifconfig wlan0 txpower 1.5" :-)
>> =9ABernhard Schmidt says, that iwn(4) uses half-dBm units and "txpower
>> 30" on iwn(4) means 15dBm physically.
> Right. I'll double-check with Bernhard as he's been knee deep in the
> iwn code. But I can tell you that the value passed from net80211 to
> ath is 2x the ifconfig power, as the ifconfig txpower is in 0.5 dBm
> units. So ifconfig wlanX txpower Y ends up storing a txpower value of
> 2*Y, and that's what ath gets. I bet iwn gets the same.
 What a mess. We have two "txpower" values -- command-line one and
 internal (2*cmd) one!

 BTW, ifconfig(8) uses very unclear wording:

 "The power argument is specified in .5 dBm units."

 It is not clear, what does it mean: that one txpower step means 0.5
 dBm and 1 on command line means 0.5 dBm, 2 means 1 dBm, and so on, up to 30
 on command line means 15dBm, OR (which seems to be true, but it is
 not clear!) it means, that you could set 0.5, 1, 1.5, and so on, and
 these numbers "true" dBm, but you cannot set 16.6, for example.

--=20
// Black Lion AKA Lev Serebryakov <lev@serebryakov.spb.ru>