From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from smtp1.u-psud.fr ([129.175.33.41]:57541 "EHLO smtp1.u-psud.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751722Ab2LDISm (ORCPT ); Tue, 4 Dec 2012 03:18:42 -0500 Message-ID: <50BDAF67.4020106@lri.fr> (sfid-20121204_091846_954525_FC6939D2) Date: Tue, 04 Dec 2012 09:08:07 +0100 From: Nicolas Cavallari MIME-Version: 1.0 To: Julian Calaby CC: Simon Wunderlich , linux-wireless@vger.kernel.org, linville@tuxdriver.com, johannes@sipsolutions.net, Simon Wunderlich , Mathias Kretschmer Subject: Re: [PATCH] mac80211: adapt slot time in IBSS mode References: <1354569690-23559-1-git-send-email-siwu@hrz.tu-chemnitz.de> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-wireless-owner@vger.kernel.org List-ID: On 04/12/2012 00:00, Julian Calaby wrote: > Hi Simon, > > On Tue, Dec 4, 2012 at 8:21 AM, Simon Wunderlich > wrote: >> In 5GHz/802.11a, we are allowed to use short slot times. Doing this >> may increases performance by 20% for legacy connections (54 MBit/s). >> I can confirm this in my tests (27% more throughput using iperf), and >> also have a small positive effect (5% more throughput) for HT rates, >> tested on 1 stream. >> >> Signed-off-by: Simon Wunderlich >> Signed-off-by: Mathias Kretschmer >> --- >> net/mac80211/ibss.c | 13 +++++++++++++ >> 1 file changed, 13 insertions(+) >> >> diff --git a/net/mac80211/ibss.c b/net/mac80211/ibss.c >> index fa862b2..1a5d29c 100644 >> --- a/net/mac80211/ibss.c >> +++ b/net/mac80211/ibss.c >> @@ -201,6 +201,19 @@ static void __ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata, >> bss_change |= BSS_CHANGED_BASIC_RATES; >> bss_change |= BSS_CHANGED_HT; >> bss_change |= BSS_CHANGED_IBSS; >> + >> + /* In 5 GHz/802.11a, we can always use short slot time. >> + * (IEEE 802.11-2012 18.3.8.7) >> + * >> + * In 2.4GHz, we must always use long slots in IBSS for compatibility >> + * reasons. >> + * (IEEE 802.11-2012 19.4.5) >> + * >> + * HT follows these specifications (IEEE 802.11-2012 20.3.18) >> + */ >> + sdata->vif.bss_conf.use_short_slot = chan->band == IEEE80211_BAND_5GHZ; >> + bss_change |= BSS_CHANGED_ERP_SLOT; >> + > > I don't know if this is done elsewhere, but this code doesn't match > the comment - there is no test for IBSS mode. > > Thanks, > Do you happen to know any code path that calls __ieee80211_sta_join_ibss() without being in IBSS mode ?