Return-path: Received: from youngberry.canonical.com ([91.189.89.112]:59175 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757476Ab3AIN2D (ORCPT ); Wed, 9 Jan 2013 08:28:03 -0500 Date: Wed, 9 Jan 2013 07:27:53 -0600 From: Seth Forshee To: Stanislaw Gruszka Cc: Johannes Berg , linux-wireless@vger.kernel.org Subject: Re: [RFC 3/3] mac80211: Disable off-channel powersave when software scans are suspended Message-ID: <20130109132753.GB18778@thinkpad-t410> (sfid-20130109_142807_675975_87EED14F) References: <1357668645-5101-1-git-send-email-seth.forshee@canonical.com> <1357668645-5101-4-git-send-email-seth.forshee@canonical.com> <20130109110343.GA13544@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20130109110343.GA13544@redhat.com> Sender: linux-wireless-owner@vger.kernel.org List-ID: On Wed, Jan 09, 2013 at 12:03:44PM +0100, Stanislaw Gruszka wrote: > Hi > > On Tue, Jan 08, 2013 at 12:10:45PM -0600, Seth Forshee wrote: > > Leaving powersave enabled while the scan is suspended requires the use > > of PS-Poll to retrieve frames buffered at the AP. PS-Poll isn't a very > > efficient means of data transfer and may not even work with drivers not > > supporting powersave. These problems can largely be avoided by simply > > disabling off-channel powersave when the scan is suspended and enabling > > it again when returning to off-channel operation. > > > > The results of this change are fantastic. Previously when using iperf I > > would see greatly decreased throughput (often dropping to 0 bits/sec for > > several seconds) and very high packet loss during software scans. This > > patch completely eliminates the packet loss and reduces the loss in > > throughput to very reasonable levels. > > I posted a patch, which remove offchannel_ps_disable argument from > ieee80211_offchannel_return, since there were possible AP and STA power > save state mismash: > > http://marc.info/?l=linux-wireless&m=135601089321822&w=2 > > It should give the same effect on performance as this patch. I guess I missed that one in my pile of post-holiday emails. I agree, it ought to have the same effect as this patch. Seth