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[185.193.85.130]) by smtp.gmail.com with ESMTPSA id j126sm9381100wmb.33.2018.04.24.07.09.33 (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 24 Apr 2018 07:09:33 -0700 (PDT) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) From: Pete Heist In-Reply-To: <87po2o7lwb.fsf@toke.dk> Date: Tue, 24 Apr 2018 16:09:32 +0200 Cc: make-wifi-fast@lists.bufferbloat.net Content-Transfer-Encoding: quoted-printable Message-Id: <1BA3CECA-8C05-4E94-9E2A-1AEA3C2F20B3@eventide.io> References: <66BDCA6E-D7C4-4E76-8591-8FDC35B09EA3@eventide.io> <871sf495vs.fsf@toke.dk> <87po2o7lwb.fsf@toke.dk> To: =?utf-8?Q?Toke_H=C3=B8iland-J=C3=B8rgensen?= X-Mailer: Apple Mail (2.3124) Subject: Re: [Make-wifi-fast] mesh deployment with ath9k driver changes X-BeenThere: make-wifi-fast@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 24 Apr 2018 14:09:35 -0000 > On Apr 24, 2018, at 3:51 PM, Toke H=C3=B8iland-J=C3=B8rgensen = wrote: >=20 > Assuming you have debugfs enabled you should be able to get aggregate > statistics from /sys/kernel/debug/ieee80211/phy0/ath9k/xmit - at least > that contains retries, but not backoff data, unfortunately. If it=E2=80=99s the ratio of "AMPDUs Completed=E2=80=9D to "AMPDUs = Retried=E2=80=9D or =E2=80=9CAMPDUs XRetried=E2=80=9D we=E2=80=99re = looking at, there=E2=80=99s a stark difference between Cabin 12 and = Cabin 28. That said, they have quite different traffic patterns, so = I=E2=80=99ll have to evaluate this in a situation where traffic patterns = are more similar... Cabin 12 (worst, two repeaters on gateway, NLOS): # cat /sys/kernel/debug/ieee80211/phy0/ath9k/xmit BE BK VI VO MPDUs Queued: 23330 735 112 304318 MPDUs Completed: 2096742 1468 144 6622260 MPDUs XRetried: 11932 509 74 274653 Aggregates: 1548313 31541 499 0 AMPDUs Queued HW: 0 0 0 0 AMPDUs Completed: 9674195 204610 22667 0 AMPDUs Retried: 1298897 22613 1025 0 AMPDUs XRetried: 45898 1189 120 0 TXERR Filtered: 7893 96 7 4 FIFO Underrun: 3 0 0 60 TXOP Exceeded: 0 0 0 0 TXTIMER Expiry: 0 0 0 0 DESC CFG Error: 0 0 0 0 DATA Underrun: 1 0 0 0 DELIM Underrun: 1 0 0 0 TX-Pkts-All: 11828767 207776 23005 6896913 TX-Bytes-All: 4193674267 197040003 23478961787460234 HW-put-tx-buf: 5318127 133067 23506 6395453 HW-tx-start: 0 0 0 0 HW-tx-proc-desc: 5690166 132905 23507 6891740 TX-Failed: 0 0 0 0 Cabin 28 (best, one repeater on gateway, LOS): # cat /sys/kernel/debug/ieee80211/phy0/ath9k/xmit BE BK VI VO MPDUs Queued: 23164 335 2 6929001 MPDUs Completed: 3218272 782 50 9311052 MPDUs XRetried: 6036 250 2 1821270 Aggregates: 6427093 20892 12 0 AMPDUs Queued HW: 0 0 0 0 AMPDUs Completed: 100430860 189959 375988 0 AMPDUs Retried: 1112896 8011 27 0 AMPDUs XRetried: 33862 449 2 0 TXERR Filtered: 2428 122 0 37 FIFO Underrun: 0 0 0 2 TXOP Exceeded: 0 0 0 0 TXTIMER Expiry: 0 0 0 0 DESC CFG Error: 0 0 0 0 DATA Underrun: 0 0 0 0 DELIM Underrun: 0 0 0 0 TX-Pkts-All: 103689030 191440 376042 11132322 TX-Bytes-All: 2783223251 210905451 601627081919930466 HW-put-tx-buf: 16245494 109264 376059 10911913 HW-tx-start: 0 0 0 0 HW-tx-proc-desc: 16282116 109333 376056 11131555 TX-Failed: 0 0 0 0 >> I wish I could cable everything, but it isn=E2=80=99t physically = practical. >> The next possibility is dual channel APs, or separate backhaul links, >> all costing something... >=20 > Yeah, a separate backhaul on a different channel would cut you > contention in half, basically. Right now, each transmission has to > occupy the channel twice... Could that cause mean RTT to go up 10x? :) In combination with having = two repeaters on one gateway=E2=80=A6