Date: Thu, 17 Jul 2008 16:31:19 GMT From: Geoffrey Mainland <mainland@eecs.harvard.edu> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/125721: [ath] Terrible throughput/high ping latency with Ubiquiti SR9/XR9 Message-ID: <200807171631.m6HGVJ3W071966@www.freebsd.org> Resent-Message-ID: <200807171640.m6HGe1PP017817@freefall.freebsd.org>
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>Number: 125721 >Category: kern >Synopsis: [ath] Terrible throughput/high ping latency with Ubiquiti SR9/XR9 >Confidential: no >Severity: serious >Priority: medium >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Thu Jul 17 16:40:01 UTC 2008 >Closed-Date: >Last-Modified: >Originator: Geoffrey Mainland >Release: 7.0-STABLE >Organization: Harvard University >Environment: FreeBSD citysense006 7.0-STABLE FreeBSD 7.0-STABLE #32: Fri Jul 11 19:21:09 UTC 2008 root@citybsd7.citysense.net:/usr/obj/usr/src/sys/CITYBSD i386 >Description: I'm running 7-CURRENT on several ALIX 3c2 boards with SR9 radios and having major performance problems: throughput on TCP streams generated by iperf often falls to zero, and, depending on the HAL I use, I see ping latencies during one of these iperf transfers of up to more than a *minute*. I've tried both the 0.9.30.13 HAL and the new 0.10.5.6 HAL. I see this bad behavior with both, but the new HAL seems even worse. I've documented my configuration and the test results at http://www.eecs.harvard.edu/~mainland/freebsd/sr9/. This includes the kernel configuration, dmesg output, pciconf output, rc.conf, statistics collected from the ath driver, appropriate sysctl values, iperf/ping output generated by my driver script and some plots showing the problem. We are trying to deploy a bunch of these nodes outdoors, using the 900MHz radios as a backhaul, so the drop-outs I see with SR9s are a major problem for us. I've also run the same tests on Soekris nodes, used different SR9s, and also tried the new XR9s on the same ALIX boards---all with similar results. We also have a bunch of Wistrom CM9s which seem to work just fine. Any idea what could be going on? >How-To-Repeat: I see this pattern of behavior with both XR9s and SR9s. It also happens on Soekris 4826 motherboards. >Fix: >Release-Note: >Audit-Trail: >Unformatted:
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