Date: Mon, 3 Dec 2012 22:33:24 +0400 (MSK)
From: Georgiewskiy Yuriy <bottleman@icf.org.ru>
To: Paul Stoaks <paul@foresight-mands.com>
cc: 'Chaoxing Lin' <Chaoxing.Lin@ultra-3eti.com>,
	linux-wireless@vger.kernel.org
Subject: RE: help: 802.11s bad performance with 802.11n enabled
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Message-ID: <alpine.DEB.2.02.1212032231160.348@icf.org.ru> (sfid-20121203_193330_586422_0AD97D9B)
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On 2012-12-03 10:21 -0800, Paul Stoaks wrote 'Georgiewskiy Yuriy' and...':

i test with ping -A size 64 and 1500 bytes, and with iperf with default parameters plus 
just -c -i1 -t100500

PS>What kind of traffic are you pushing through (packet sizes?)  Are they fixed
PS>size, fixed rate, or ...?
PS>
PS>Paul
PS>
PS>
PS>-----Original Message-----
PS>From: linux-wireless-owner@vger.kernel.org
PS>[mailto:linux-wireless-owner@vger.kernel.org] On Behalf Of Georgiewskiy
PS>Yuriy
PS>Sent: Monday, December 03, 2012 7:44 AM
PS>To: Chaoxing Lin
PS>Cc: linux-wireless@vger.kernel.org
PS>Subject: RE: help: 802.11s bad performance with 802.11n enabled
PS>
PS>On 2012-12-03 14:56 -0000, Chaoxing Lin wrote Georgiewskiy Yuriy:
PS>
PS>CL>CL>For experiment, I changed ath9k driver to disable 802.11n packet
PS>aggregation. The network becomes much better.
PS>CL>CL>It's as stable as running 802.11a only mode.
PS>CL>CL>So it seems that the aggregation plays a big role in in-stability of
PS>802.11s network with 802.11n.
PS>CL>CL>Any one has any idea why?
PS>CL>
PS>CL>Can you post a patch? i want test this too.
PS>CL>
PS>CL>The change is easy
PS>CL>In ath9k/init.c
PS>CL>Function ath9k_set_hw_capab()
PS>CL>Replace below
PS>CL>    if (sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_HT)
PS>CL>         hw->flags |= IEEE80211_HW_AMPDU_AGGREGATION; with
PS>CL>	hw->flags &= ~IEEE80211_HW_AMPDU_AGGREGATION;
PS>
PS>On first look in my case disabled aggregation reduces packet loss, link is
PS>more reliable, but it's also drop throughput to 15-20 Mbits/sec from about
PS>~50 with aggregation enabled.
PS>
PS>C ?????????                       With Best Regards
PS>???????????? ????.                Georgiewskiy Yuriy
PS>+7 4872 711666                    +7 4872 711666
PS>???? +7 4872 711143               fax +7 4872 711143
PS>???????? ??? "?? ?? ??????"       IT Service Ltd
PS>http://nkoort.ru                  http://nkoort.ru
PS>JID: GHhost@icf.org.ru            JID: GHhost@icf.org.ru
PS>YG129-RIPE                        YG129-RIPE
PS>
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C ?????????                       With Best Regards
???????????? ????.                Georgiewskiy Yuriy
+7 4872 711666                    +7 4872 711666
???? +7 4872 711143               fax +7 4872 711143
???????? ??? "?? ?? ??????"       IT Service Ltd
http://nkoort.ru                  http://nkoort.ru
JID: GHhost@icf.org.ru            JID: GHhost@icf.org.ru
YG129-RIPE                        YG129-RIPE
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