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Date:      Sun, 22 Mar 2015 17:54:01 +0000 (UTC)
From:      Adrian Chadd <adrian@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r280349 - head/sys/net80211
Message-ID:  <201503221754.t2MHs1Uj023539@svn.freebsd.org>
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Author: adrian
Date: Sun Mar 22 17:54:00 2015
New Revision: 280349
URL: https://svnweb.freebsd.org/changeset/base/280349

Log:
  Initialise the pps / packet tracking timestamp so 11n aggregation works again.
  
  There's a bug in the ticks handling where when initialised at '0', once
  the ticks counter wrapped the comparison math would never trigger.
  The pps calculation would never happen, and thus aggregation was never
  enabled.
  
  It manifests itself as "oh you only get 11n transmit aggregation for the
  first 10 minutes of uptime."
  
  I'm sure there are other ticks related issues lurking in net80211.
  
  Tested:
  
  * ath / iwn, both with 'wlandebug +11n' and a little bit of iperf to
    kick off the transmit A-MPDU negotiation once the pps gets high enough.

Modified:
  head/sys/net80211/ieee80211_ht.c

Modified: head/sys/net80211/ieee80211_ht.c
==============================================================================
--- head/sys/net80211/ieee80211_ht.c	Sun Mar 22 17:29:14 2015	(r280348)
+++ head/sys/net80211/ieee80211_ht.c	Sun Mar 22 17:54:00 2015	(r280349)
@@ -1047,6 +1047,7 @@ ieee80211_ht_node_init(struct ieee80211_
 		tap = &ni->ni_tx_ampdu[tid];
 		tap->txa_tid = tid;
 		tap->txa_ni = ni;
+		tap->txa_lastsample = ticks;
 		/* NB: further initialization deferred */
 	}
 	ni->ni_flags |= IEEE80211_NODE_HT | IEEE80211_NODE_AMPDU;
@@ -1216,6 +1217,7 @@ ieee80211_ht_wds_init(struct ieee80211_n
 	for (tid = 0; tid < WME_NUM_TID; tid++) {
 		tap = &ni->ni_tx_ampdu[tid];
 		tap->txa_tid = tid;
+		tap->txa_lastsample = ticks;
 	}
 	/* NB: AMPDU tx/rx governed by IEEE80211_FHT_AMPDU_{TX,RX} */
 	ni->ni_flags |= IEEE80211_NODE_HT | IEEE80211_NODE_AMPDU;
@@ -1691,6 +1693,7 @@ ampdu_tx_setup(struct ieee80211_tx_ampdu
 {
 	callout_init(&tap->txa_timer, CALLOUT_MPSAFE);
 	tap->txa_flags |= IEEE80211_AGGR_SETUP;
+	tap->txa_lastsample = ticks;
 }
 
 static void
@@ -1718,8 +1721,12 @@ ampdu_tx_stop(struct ieee80211_tx_ampdu 
 	 */
 	bar_stop_timer(tap);
 
-	tap->txa_lastsample = 0;
+	/*
+	 * Reset packet estimate.
+	 */
+	tap->txa_lastsample = ticks;
 	tap->txa_avgpps = 0;
+
 	/* NB: clearing NAK means we may re-send ADDBA */ 
 	tap->txa_flags &= ~(IEEE80211_AGGR_SETUP | IEEE80211_AGGR_NAK);
 }

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