Date: Tue, 9 Aug 2011 14:28:25 +0400 From: Lev Serebryakov <lev@serebryakov.spb.ru> To: Adrian Chadd <adrian@freebsd.org> Cc: freebsd-wireless@freebsd.org Subject: Re: Bad host-vased AP performace -- and qouple of questions about FreeBSD WiFi stack tuning Message-ID: <347137729.20110809142825@serebryakov.spb.ru> 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%2BWd-=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>
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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>
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