Bug 163237 - [ath] AR5416 as HostAP. Delays among clients when a client is in Power saving mode
Summary: [ath] AR5416 as HostAP. Delays among clients when a client is in Power saving...
Status: Open
Alias: None
Product: Base System
Classification: Unclassified
Component: wireless (show other bugs)
Version: 10.0-CURRENT
Hardware: Any Any
: Normal Affects Only Me
Assignee: freebsd-wireless (Nobody)
Depends on:
Reported: 2011-12-13 08:40 UTC by Gustau Pérez
Modified: 2018-05-28 19:47 UTC (History)
0 users

See Also:


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Description Gustau Pérez 2011-12-13 08:40:13 UTC
  This is the environment:

  I'm using an AR5416 card acting as an AP with hostap in 11g mode. I'm running g mode because I did not have time to test the 11n work yet. The box is running CURRENT/AMD64.

  These are the symptoms:

  A few days ago I began to see very big delays between the AP and my laptop (which has an AR9287 with FreeBSD/AMD64 CURRENT). I tried a simple icmp with 1 second between pings. It is quite curious thing that the delays increase from 30ms until around 100ms (those times are in the same order of magnitude of a ping to google) and then they fall til 30ms again. It did not work like that.

   I tested with different clients (an iPhone, a laptop running FreeBSD with an Intel 3945, an asus eeePC laptop with windows7 and other devices). All of them showed the same behavior. No matter if I'm accessing the HostAP box or trying to access internet, everything takes long. 

   The bisect lead me to commit r227364, which is one quite large. Running the previous commit fixes it.

How-To-Repeat: Compile a custom kernel with r227364 in a box with an AR5416 and use the box as an AP.
Comment 1 Gustau Pérez 2011-12-14 18:55:33 UTC
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 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

  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 
icmp messages).

   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.
Comment 2 Adrian Chadd freebsd_committer 2012-03-11 15:55:21 UTC
Responsible Changed
From-To: freebsd-bugs->freebsd-wireless

Comment 3 Eitan Adler freebsd_committer freebsd_triage 2018-05-28 19:47:00 UTC
batch change:

For bugs that match the following
-  Status Is In progress 
- Untouched since 2018-01-01.
- Affects Base System OR Documentation


Reset to open status.

I did a quick pass but if you are getting this email it might be worthwhile to double check to see if this bug ought to be closed.