Date: Thu, 1 Dec 2011 00:06:39 +0800 From: Adrian Chadd <adrian@freebsd.org> To: Viet-Ha Pham <hapvbk@yahoo.co.uk> Cc: freebsd-net@freebsd.org, Bernhard Schmidt <bschmidt@freebsd.org> Subject: Re: Wifi throughput test issue (FreeBSD 8.2) Message-ID: <CAJ-Vmo=B3H3_Wefhq4fKQQ7LiYF27oQ06osm4QzuWKT2a3wDxA@mail.gmail.com> In-Reply-To: <5939430EC6AF43B79CB9BE99940E9B91@PC> References: <69C75F6ECC9646C79374299EDF0E4304@PC> <CAAgh0_Ym0Np4Py-aaxH=bEJcSJPAKcx2CFECMtgSD=%2B%2BVhUvLQ@mail.gmail.com> <5939430EC6AF43B79CB9BE99940E9B91@PC>
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Hi, Hm. Selecting a static rate would mean that you'd end up populating the rate control statistics with more "wins" for that particular TX rate, so when you go back to "any", it will choose 54mbit more often. I suggest looking at the code in sys/dev/ath/ath_rate/sample/sample.[ch] and see what's going on. You can investigate the current statistics by "sysctl dev.ath.X.sample_stats=1" and then check dmesg. It sounds like your noise is causing some tx failures to occur at higher rates, which makes sample back off very quickly. It may not then sample the higher rates often enough if it sees failures early on. Adrian
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