* [PATCH] mac80211: adapt slot time in IBSS mode @ 2012-12-03 21:21 Simon Wunderlich 2012-12-03 23:00 ` Julian Calaby 2012-12-04 14:54 ` Johannes Berg 0 siblings, 2 replies; 6+ messages in thread From: Simon Wunderlich @ 2012-12-03 21:21 UTC (permalink / raw) To: linux-wireless; +Cc: linville, johannes, Simon Wunderlich, Mathias Kretschmer 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 <siwu@hrz.tu-chemnitz.de> Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de> --- 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; + sdata->vif.bss_conf.ibss_joined = true; sdata->vif.bss_conf.ibss_creator = creator; ieee80211_bss_info_change_notify(sdata, bss_change); -- 1.7.10.4 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] mac80211: adapt slot time in IBSS mode 2012-12-03 21:21 [PATCH] mac80211: adapt slot time in IBSS mode Simon Wunderlich @ 2012-12-03 23:00 ` Julian Calaby 2012-12-04 8:08 ` Nicolas Cavallari 2012-12-04 10:42 ` Simon Wunderlich 2012-12-04 14:54 ` Johannes Berg 1 sibling, 2 replies; 6+ messages in thread From: Julian Calaby @ 2012-12-03 23:00 UTC (permalink / raw) To: Simon Wunderlich Cc: linux-wireless, linville, johannes, Simon Wunderlich, Mathias Kretschmer Hi Simon, On Tue, Dec 4, 2012 at 8:21 AM, Simon Wunderlich <simon.wunderlich@s2003.tu-chemnitz.de> 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 <siwu@hrz.tu-chemnitz.de> > Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de> > --- > 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, -- Julian Calaby Email: julian.calaby@gmail.com Profile: http://www.google.com/profiles/julian.calaby/ .Plan: http://sites.google.com/site/juliancalaby/ ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] mac80211: adapt slot time in IBSS mode 2012-12-03 23:00 ` Julian Calaby @ 2012-12-04 8:08 ` Nicolas Cavallari 2012-12-04 22:07 ` Julian Calaby 2012-12-04 10:42 ` Simon Wunderlich 1 sibling, 1 reply; 6+ messages in thread From: Nicolas Cavallari @ 2012-12-04 8:08 UTC (permalink / raw) To: Julian Calaby Cc: Simon Wunderlich, linux-wireless, linville, johannes, Simon Wunderlich, Mathias Kretschmer On 04/12/2012 00:00, Julian Calaby wrote: > Hi Simon, > > On Tue, Dec 4, 2012 at 8:21 AM, Simon Wunderlich > <simon.wunderlich@s2003.tu-chemnitz.de> 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 <siwu@hrz.tu-chemnitz.de> >> Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de> >> --- >> 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 ? ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] mac80211: adapt slot time in IBSS mode 2012-12-04 8:08 ` Nicolas Cavallari @ 2012-12-04 22:07 ` Julian Calaby 0 siblings, 0 replies; 6+ messages in thread From: Julian Calaby @ 2012-12-04 22:07 UTC (permalink / raw) To: Nicolas Cavallari Cc: Simon Wunderlich, linux-wireless, linville, johannes, Simon Wunderlich, Mathias Kretschmer Hi Nicolas, On Tue, Dec 4, 2012 at 7:08 PM, Nicolas Cavallari <Nicolas.Cavallari@lri.fr> wrote: > On 04/12/2012 00:00, Julian Calaby wrote: >> Hi Simon, >> >> On Tue, Dec 4, 2012 at 8:21 AM, Simon Wunderlich >> <simon.wunderlich@s2003.tu-chemnitz.de> 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 <siwu@hrz.tu-chemnitz.de> >>> Signed-off-by: Mathias Kretschmer <mathias.kretschmer@fokus.fraunhofer.de> >>> --- >>> 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 ? Groan. I clearly need to read patches better. Thanks, -- Julian Calaby Email: julian.calaby@gmail.com Profile: http://www.google.com/profiles/julian.calaby/ .Plan: http://sites.google.com/site/juliancalaby/ ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] mac80211: adapt slot time in IBSS mode 2012-12-03 23:00 ` Julian Calaby 2012-12-04 8:08 ` Nicolas Cavallari @ 2012-12-04 10:42 ` Simon Wunderlich 1 sibling, 0 replies; 6+ messages in thread From: Simon Wunderlich @ 2012-12-04 10:42 UTC (permalink / raw) To: Julian Calaby Cc: Simon Wunderlich, linux-wireless, linville, johannes, Simon Wunderlich, Mathias Kretschmer [-- Attachment #1: Type: text/plain, Size: 358 bytes --] Hey Julian, On Tue, Dec 04, 2012 at 10:00:33AM +1100, Julian Calaby wrote: > > I don't know if this is done elsewhere, but this code doesn't match > the comment - there is no test for IBSS mode. As Nicolas pointed out, this is only called in IBSS - it is part of the ibss join/initialization code, so this is not a problem. :) Cheers, Simon [-- Attachment #2: Digital signature --] [-- Type: application/pgp-signature, Size: 198 bytes --] ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] mac80211: adapt slot time in IBSS mode 2012-12-03 21:21 [PATCH] mac80211: adapt slot time in IBSS mode Simon Wunderlich 2012-12-03 23:00 ` Julian Calaby @ 2012-12-04 14:54 ` Johannes Berg 1 sibling, 0 replies; 6+ messages in thread From: Johannes Berg @ 2012-12-04 14:54 UTC (permalink / raw) To: Simon Wunderlich Cc: linux-wireless, linville, Simon Wunderlich, Mathias Kretschmer On Mon, 2012-12-03 at 22:21 +0100, 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. Applied. johannes ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2012-12-04 22:07 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2012-12-03 21:21 [PATCH] mac80211: adapt slot time in IBSS mode Simon Wunderlich 2012-12-03 23:00 ` Julian Calaby 2012-12-04 8:08 ` Nicolas Cavallari 2012-12-04 22:07 ` Julian Calaby 2012-12-04 10:42 ` Simon Wunderlich 2012-12-04 14:54 ` Johannes Berg
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox