From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-bw0-f46.google.com ([209.85.214.46]:36896 "EHLO mail-bw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751862Ab0HGAHI (ORCPT ); Fri, 6 Aug 2010 20:07:08 -0400 Received: by bwz3 with SMTP id 3so287799bwz.19 for ; Fri, 06 Aug 2010 17:07:07 -0700 (PDT) From: Christian Lamparter To: linux-wireless@vger.kernel.org Subject: [RFC] minstrel_ht: fill out more than 3 rates Date: Sat, 7 Aug 2010 00:07:52 +0200 Cc: Felix Fietkau MIME-Version: 1.0 Content-Type: Text/Plain; charset="us-ascii" Message-Id: <201008070007.53294.chunkeey@googlemail.com> Sender: linux-wireless-owner@vger.kernel.org List-ID: Hello Felix, I've stumbled into this conundrum a while ago... then as usual: forgot that it existed, until yesterday: As you know minstrel (our non ht fallback) enables mrr-mode only if the driver sets hw->max_rates to 4 or more. minstrel_ht - on the other hand - just prepares a set of 3 rates, so at least one additional retry with different tx-vectors remains unused... How the last tries should be used is up for debate, I've opted out for lowest possible MCS. (although, some devices may also use a legacy rate for the final tries...) And the reason why I think it's worth to do an additional round: The reordering penalty for lost MPDUs on the receiver- side can be as high as 100ms, which is quite expensive compared to some extra airtime... --- diff --git a/net/mac80211/rc80211_minstrel_ht.c b/net/mac80211/rc80211_minstrel_ht.c index c5b4659..5f44c0b 100644 --- a/net/mac80211/rc80211_minstrel_ht.c +++ b/net/mac80211/rc80211_minstrel_ht.c @@ -584,7 +584,7 @@ minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta, struct minstrel_ht_sta_priv *msp = priv_sta; struct minstrel_ht_sta *mi = &msp->ht; struct minstrel_priv *mp = priv; - int sample_idx; + int sample_idx, i = 0; if (rate_control_send_low(sta, priv_sta, txrc)) return; @@ -595,21 +595,29 @@ minstrel_ht_get_rate(void *priv, struct ieee80211_sta *sta, void *priv_sta, info->flags |= mi->tx_flags; sample_idx = minstrel_get_sample_rate(mp, mi); if (sample_idx >= 0) { - minstrel_ht_set_rate(mp, mi, &ar[0], sample_idx, + minstrel_ht_set_rate(mp, mi, &ar[i++], sample_idx, txrc, true, false); - minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate, + minstrel_ht_set_rate(mp, mi, &ar[i++], mi->max_tp_rate, txrc, false, true); info->flags |= IEEE80211_TX_CTL_RATE_CTRL_PROBE; } else { - minstrel_ht_set_rate(mp, mi, &ar[0], mi->max_tp_rate, + minstrel_ht_set_rate(mp, mi, &ar[i++], mi->max_tp_rate, txrc, false, false); - minstrel_ht_set_rate(mp, mi, &ar[1], mi->max_tp_rate2, + minstrel_ht_set_rate(mp, mi, &ar[i++], mi->max_tp_rate2, txrc, false, true); } - minstrel_ht_set_rate(mp, mi, &ar[2], mi->max_prob_rate, txrc, false, true); + minstrel_ht_set_rate(mp, mi, &ar[i++], mi->max_prob_rate, + txrc, false, true); - ar[3].count = 0; - ar[3].idx = -1; + for (;i < mp->hw->max_rates; i++) { + minstrel_ht_set_rate(mp, mi, &ar[i++], 0, + txrc, false, true); + } + + for (; i < IEEE80211_TX_MAX_RATES; i++) { + ar[i].count = 0; + ar[i].idx = -1; + } mi->total_packets++;