From owner-freebsd-wireless@FreeBSD.ORG Fri Sep 9 11:06:04 2011 Return-Path: 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 696A5106564A for ; Fri, 9 Sep 2011 11:06:04 +0000 (UTC) (envelope-from adrian.chadd@gmail.com) Received: from mail-yx0-f182.google.com (mail-yx0-f182.google.com [209.85.213.182]) by mx1.freebsd.org (Postfix) with ESMTP id 1A1208FC12 for ; Fri, 9 Sep 2011 11:06:03 +0000 (UTC) Received: by yxk36 with SMTP id 36so1766442yxk.13 for ; Fri, 09 Sep 2011 04:06:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type; bh=cxO7r1L1HvSR+cIMuLzjUL4lyHGV8Db1t/gAs4+9JOw=; b=tWnJKoXrg1u+prr4c2ilzCcfxel63u1c9n42HXOoPmgnICACfAZ20W1VHDVZbttfB7 wSCjRtjSdUMN0OH7WIVSBCtXOYSjwBE767qbtY0rSdcSoXinW9DbKBghZFPEAeKKrZ8g j97cWS1/j2JIokXeoTXpKFFuKwOZ1vxqBuAeE= MIME-Version: 1.0 Received: by 10.236.173.131 with SMTP id v3mr10943004yhl.112.1315566363172; Fri, 09 Sep 2011 04:06:03 -0700 (PDT) Sender: adrian.chadd@gmail.com Received: by 10.236.103.6 with HTTP; Fri, 9 Sep 2011 04:06:03 -0700 (PDT) In-Reply-To: <1853154884.20110909145338@serebryakov.spb.ru> References: <663133681.20110907193747@serebryakov.spb.ru> <437702009.20110907235248@serebryakov.spb.ru> <426917282.20110908125907@serebryakov.spb.ru> <4610390305.20110908154130@serebryakov.spb.ru> <1705262661.20110908180850@serebryakov.spb.ru> <458771414.20110908183656@serebryakov.spb.ru> <4910491962.20110908185213@serebryakov.spb.ru> <1273865639.20110908191303@serebryakov.spb.ru> <1607911768.20110909113824@serebryakov.spb.ru> <1853154884.20110909145338@serebryakov.spb.ru> Date: Fri, 9 Sep 2011 19:06:03 +0800 X-Google-Sender-Auth: CuG6UtaH_4wM8-4wXTSMZPvCLjQ Message-ID: From: Adrian Chadd To: Lev Serebryakov Content-Type: text/plain; charset=ISO-8859-1 Cc: freebsd-wireless@freebsd.org Subject: Re: AP performance (again): txpower regulation 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." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 09 Sep 2011 11:06:04 -0000 Right, but this is where you now do some more digging. :) (This is how I started hacking on atheros/net80211 stuff about 18 months ago. I was in the same situation you were, only with the Ubiquiti 11n and SR-2 NICs.) I'd suggest looking at the output of athstats whilst you're doing traffic: $ athstats 1 And look at the output of the sample rate control algorithm: # sysctl dev.ath.0.sample_stats=1 (then check dmesg) Let's split it into two halves: TX and RX. For TX errors, you'll see things like ackbad, long/short retries. For RX errors, you'll see lots of CRC errors. You'll also see OFDM/CCK errors if your environment is noisy (and you've got ANI enabled.) Forcing the tx/rx antenna will likely fix the stability of the ACKs seen. As for the throughput, look at the output of TX/RX, look at the per-rate retry and error rates being seen, and start to figure out what's going on. You can use iperf UDP tests in each direction to test out one-way traffic - TCP stresses both directions; UDP stresses data in one and 802.11 ACKs in the other. Finally, I bet yes - running the NIC at half its rated TX power is likely going to make things easier to deal with. It won't be using the full TX power at higher rates anyway- ie, although the NIC is rated at 600mW, that'll be at the lowest TX rates (1MBit), I bet at 54MBit it's only transmitting at 100mW. Since you want to get higher throughput, why run the NIC at a higher TX power than what the 54mbit rate will TX at? :) Adrian