Bug 31922

Summary:	ath5k: Decreased throughput in IBSS or 802.11n mode
Product:	Drivers	Reporter:	Jeff Cook (jeff)
Component:	network-wireless	Assignee:	drivers_network-wireless (drivers_network-wireless)
Status:	CLOSED OBSOLETE
Severity:	normal	CC:	alan, florian, linville, maciej.rutecki, me, mickflemm, pedretti.fabio, rjw
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	2.6.38	Subsystem:
Regression:	Yes	Bisected commit-id:
Bug Depends on:
Bug Blocks:	27352

Description Jeff Cook 2011-03-26 20:06:58 UTC

A lot of discussion on this bug has already occurred on Bug #31452. Please refer to that bug for complete detail.

Since 2.6.38, throughput on wireless-n and ad-hoc networks has been very poor (unusably poor). Almost 100% packet loss in my ad-hoc setup with a 5k card as host; one would make it through only rarely, a couple times a minute or less (empirically, from watching in Wireshark).

Reverting 8aec7af9 (with the patch posted on bug #31452) fixes this problem on ath5k for me.

This bug also affects ath9k. I experienced it there on an ad-hoc client. I haven't retested or bisected that kernel yet but still intend to do so if nobody does it before me. Discussion related to ath9k should occur on bug #31452.

Comment 1 John W. Linville 2011-03-28 13:24:37 UTC

Nick, any thoughts on what might be wrong with 8aec7af9?

Comment 2 Nick Kossifidis 2011-03-28 13:41:30 UTC

@Jeff: Do you use fixed-freq when setting up ad-hoc mode ?

Comment 3 Jeff Cook 2011-03-30 23:57:09 UTC

I'm not sure which mode I use as I've just been setting it up through nm-applet. I'm not at the workstation now, but what would be useful to run when I get back after I set up the network? iwconfig, ifconfig, etc.?

Comment 4 Nick Kossifidis 2011-03-31 00:13:47 UTC

Use the iw command when setting up ad-hoc mode etc and use the fixed-freq argument (check out iw's help). Fixed-freq locks the card to a single channel and doesn't do bg scanning so it'll help us see if your problem is related to channel switching as a first step.

Comment 5 Florian Mickler 2011-05-01 14:16:33 UTC

Jeff, any news on this?