kern/163237: AR5416 as HostAP. Delays among clients when
gperez at entel.upc.edu
Wed Dec 14 20:20:10 UTC 2011
The following reply was made to PR kern/163237; it has been noted by GNATS.
From: =?ISO-8859-1?Q?Gustau_P=E9rez?= <gperez at entel.upc.edu>
To: bug-followup at FreeBSD.org
Subject: Re: kern/163237: AR5416 as HostAP. Delays among clients when
Date: Wed, 14 Dec 2011 19:55:33 +0100
Further tests show that when an iPhone associates with the AP, the
problem appears. As soon as the iPhone deassociates the latency goes down.
Some tests where made. The tree elements during the tests were: the AP
Box, an iPhone and a FreeBSD 10/CURRENT laptop. The laptop was sending
icmp messages to the AP while the iPhone was associated.
The AP Box has the 192.168.1.100/24 address. The
A first test consisted of sending 10 icmp messages per second from the
laptop to the AP Box. The command used was:
ping -c 0.1 192.168.1.100
When doing this test the latency was constantly growing untill the
time taken to reach the box and back got up to around 110ms, then it
fell to around 10ms (which quite big, I would say three orders of
magnitude.I would have expected about 0.5ms). The frequency of the
phenomenon was of around 80 icmp messages (that is about 8 seconds of
A second test consisted of sending 100 icmp messages per second to
the box. Now the behavior was different. The latency keep falling to
around 20ms and then it suddenly grew to around 110ms. The frequency
this time was of about 8 icmp messages.
I can obtain traces and upload them somewhere and share the links.
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