Return-path: Received: from mail.net.t-labs.tu-berlin.de ([130.149.220.252]:40845 "EHLO mail.net.t-labs.tu-berlin.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932814Ab3CDWaM (ORCPT ); Mon, 4 Mar 2013 17:30:12 -0500 From: Thomas Huehn To: linville@tuxdriver.com Cc: linux-wireless@vger.kernel.org, johannes@sipsolutions.net, nbd@openwrt.org, thomas@net.t-labs.tu-berlin.de Subject: [PATCH v4 4/7] mac80211: extend minstrel's rate sampling to avoid unsampled rates Date: Mon, 4 Mar 2013 23:30:04 +0100 Message-Id: <1362436208-75786-5-git-send-email-thomas@net.t-labs.tu-berlin.de> (sfid-20130304_233031_561704_F30BDCE5) In-Reply-To: <1362436208-75786-1-git-send-email-thomas@net.t-labs.tu-berlin.de> References: <1362436208-75786-1-git-send-email-thomas@net.t-labs.tu-berlin.de> Sender: linux-wireless-owner@vger.kernel.org List-ID: Minstrel's decision which rate should be directly sampled within the 1st mrr stage is limited to such rates faster than the current max throughput rate. All rates below the current max. throughput rate are indirectly sampled via the 2nd mrr stage. This approach leads to deprecated per rate statistics and therfore a deprecated mrr chain setup. This patch uses the sampling approach from minstrel_ht. A counter is added to sum all indirect sample attempts per rate. After 20 indirect sampling attempts the rate is directly sampled within the 1st mrr stage. Therefore more up-to-date statistics for all rates are maintained and used to setup the mrr chain. Signed-off-by: Thomas Huehn --- net/mac80211/rc80211_minstrel.c | 13 +++++++++---- net/mac80211/rc80211_minstrel.h | 1 + 2 files changed, 10 insertions(+), 4 deletions(-) diff --git a/net/mac80211/rc80211_minstrel.c b/net/mac80211/rc80211_minstrel.c index 152bb0e..aa59f29 100644 --- a/net/mac80211/rc80211_minstrel.c +++ b/net/mac80211/rc80211_minstrel.c @@ -85,7 +85,8 @@ minstrel_update_stats(struct minstrel_priv *mp, struct minstrel_sta_info *mi) if (!usecs) usecs = 1000000; - if (mr->attempts) { + if (unlikely(mr->attempts > 0)) { + mr->sample_skipped = 0; mr->cur_prob = MINSTREL_FRAC(mr->success, mr->attempts); mr->succ_hist += mr->success; mr->att_hist += mr->attempts; @@ -93,7 +94,8 @@ minstrel_update_stats(struct minstrel_priv *mp, struct minstrel_sta_info *mi) mr->cur_prob, EWMA_LEVEL); mr->cur_tp = mr->probability * (1000000 / usecs); - } + } else + mr->sample_skipped++; mr->last_success = mr->success; mr->last_attempts = mr->attempts; @@ -282,9 +284,12 @@ minstrel_get_rate(void *priv, struct ieee80211_sta *sta, rate_sampling = true; /* Decide if direct ( 1st mrr stage) or indirect (2nd mrr stage) - * rate sampling method should be used */ + * rate sampling method should be used. + * Respect such rates that are not sampled for 20 interations. + */ if (mrr_capable && - msr->perfect_tx_time > mi->r[ndx].perfect_tx_time) + msr->perfect_tx_time > mi->r[ndx].perfect_tx_time && + msr->sample_skipped < 20) indirect_rate_sampling = true; if (!indirect_rate_sampling) { diff --git a/net/mac80211/rc80211_minstrel.h b/net/mac80211/rc80211_minstrel.h index 5fb5cb8..200b7e3 100644 --- a/net/mac80211/rc80211_minstrel.h +++ b/net/mac80211/rc80211_minstrel.h @@ -43,6 +43,7 @@ struct minstrel_rate { u32 attempts; u32 last_attempts; u32 last_success; + u8 sample_skipped; /* parts per thousand */ u32 cur_prob; -- 1.8.1.1