From: Felix Fietkau <nbd@openwrt.org>
To: Andi Kleen <andi@firstfloor.org>
Cc: Larry Finger <Larry.Finger@lwfinger.net>,
Michael Buesch <mb@bu3sch.de>,
linux-wireless@vger.kernel.org,
John Linville <linville@tuxdriver.com>
Subject: Re: rate instability in wireless stack
Date: Mon, 05 Jan 2009 17:36:34 +0100 [thread overview]
Message-ID: <49623712.4060106@openwrt.org> (raw)
In-Reply-To: <20090105163553.GU496@one.firstfloor.org>
Andi Kleen wrote:
> Ok, but I see the same thing with two different cards, with different
> chipsets (RaLink and RealTek). You think they both have that problem?
Yes, I think that's not unlikely.
>> Maybe we can see more if you provide some minstrel stats after
>> you've pushed more traffic through the link - 25-50 packets is not
>> nearly enough for getting an accurate view of how good the link is.
>> Try to push through a few megabytes of data...
>
> Here are the statistics after a few MB.
>
> rate throughput ewma prob this prob this succ/attempt success attempts
> TtP 1 0.9 97.9 100.0 1( 1) 19284 21249
> 2 0.0 0.0 0.0 0( 0) 0 101
> 5.5 0.0 0.0 0.0 0( 0) 0 104
> 11 0.0 0.0 0.0 0( 0) 253 397
> 6 0.0 0.0 0.0 0( 0) 0 103
> 9 0.0 0.0 0.0 0( 0) 0 106
> 12 0.0 0.0 0.0 0( 0) 0 107
> 18 0.0 0.0 0.0 0( 0) 0 104
> 24 0.0 0.0 0.0 0( 0) 0 111
> 36 0.0 0.0 0.0 0( 0) 0 120
> 48 0.0 0.0 0.0 0( 0) 0 179
> 54 0.0 0.0 0.0 0( 0) 0 253
>
> Total packet count:: ideal 9023 lookaround 474
According to the rate control's view, only the 1M has a usable
success probability. It's rather insteresting that 11M is the only
other rate that had some successes. With this kind of results, the
only two options that I can think of are either a systematic tx
status reporting error (false negative for the IEEE80211_TX_STAT_ACK
flag), or something PHY related.
I think the latter is more likely.
- Felix
next prev parent reply other threads:[~2009-01-05 16:36 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-04 16:46 rate instability in wireless stack Andi Kleen
2009-01-04 16:36 ` Michael Buesch
2009-01-04 17:41 ` Andi Kleen
2009-01-05 0:29 ` Larry Finger
2009-01-05 2:53 ` Andi Kleen
2009-01-05 3:55 ` Larry Finger
2009-01-05 5:02 ` Andi Kleen
2009-01-05 4:59 ` Larry Finger
2009-01-05 5:48 ` Andi Kleen
2009-01-05 5:51 ` Larry Finger
2009-01-05 8:17 ` Johannes Berg
2009-01-05 12:54 ` Andi Kleen
2009-01-05 13:32 ` Felix Fietkau
2009-01-05 14:23 ` Andi Kleen
2009-01-05 14:41 ` Felix Fietkau
2009-01-05 15:24 ` Andi Kleen
2009-01-05 15:25 ` Felix Fietkau
2009-01-05 16:35 ` Andi Kleen
2009-01-05 16:36 ` Felix Fietkau [this message]
2009-01-05 17:11 ` Andi Kleen
2009-01-05 17:01 ` Felix Fietkau
2009-01-05 19:33 ` Hin-Tak Leung
2009-01-05 20:16 ` Larry Finger
2009-01-05 4:22 ` Larry Finger
-- strict thread matches above, loose matches on Subject: below --
2009-01-07 6:46 Martín Ernesto Barreyro
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