mac80211: adapt slot time in IBSS mode

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>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Simon Wunderlich 2012-12-03 22:21:30 +01:00 committed by Johannes Berg
parent da29d2a578
commit 2f91a96799

View File

@ -201,6 +201,20 @@ 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);