Author: adrian
Date: Mon Sep 28 00:59:07 2015
New Revision: 288318
URL: https://svnweb.freebsd.org/changeset/base/288318
Log:
Migrate the fast-frames transmit support away from using the txa_private
field and into a separate fast-frames staging pointer in ieee80211_node.
The A-MPDU TX path allows txa_private to be used by drivers. So it will
clash with any attempt to use fast-frames. Now, fast-frames is not really
anything special - it's just a custom ethernet frame type that contains
two MSDUs into one MPDU. So all the NIC has to support doing is transmitting
up to a 4KiB frame with an arbitrary ethertype and bam! Fast-frames.
However, using txa_private means we can /either/ do fast-frames or A-MPDU TX,
so fast frames has been turned off in the Atheros HAL for 11n chipsets.
This is a bit silly - it actually means that 802.11 performance to/from
11abg Atheros chips is actually better than between an 11abg atheros device
and an 11n Atheros device.
So:
* create a new mbuf staging queue for fast frames. It only queues a single
frame in the staging queue (and there's a top-level ic staging queue
used for expiry/tracking) so it's just an mbuf pointer per TID.
* Still use the ampdu TX packet counter to determine whether to do
aggregation or not. It'll double count if we start doing both A-MPDU TX
and fast frames, but that's not all that important right now.
* Initialise the pps tracker so ticks isn't zero. This ensures that
fast-frames actually gets used - without it, the ticks math overflows
and the pps math always sets txa_pps=0. This is the same bug that
plagued A-MPDU TX starting logic.
This actually allows fast-frames transmit to occur between the AR9331
(in 11n HT/20 mode) and AR9170 (if_otus) in 11bg mode.
Now, this is a great big no-op on atheros 11n hardware, so don't worry.
It may mean you start seeing more reliable fast-frames transmission on
11abg hardware which may expose some more amusing bugs.
TODO:
* further testing and debugging of all of this before flipping on
fast-frames in if_ath (for 11n) and if_otus.
Modified:
head/sys/net80211/ieee80211_node.h
head/sys/net80211/ieee80211_superg.c
Modified: head/sys/net80211/ieee80211_node.h
==============================================================================
--- head/sys/net80211/ieee80211_node.h Mon Sep 28 00:51:24 2015
(r288317)
+++ head/sys/net80211/ieee80211_node.h Mon Sep 28 00:59:07 2015
(r288318)
@@ -219,6 +219,9 @@ struct ieee80211_node {
struct ieee80211_tx_ampdu ni_tx_ampdu[WME_NUM_TID];
struct ieee80211_rx_ampdu ni_rx_ampdu[WME_NUM_TID];
+ /* fast-frames state */
+ struct mbuf * ni_tx_superg[WME_NUM_TID];
+
/* others */
short ni_inact; /* inactivity mark count */
short ni_inact_reload;/* inactivity reload value */
Modified: head/sys/net80211/ieee80211_superg.c
==============================================================================
--- head/sys/net80211/ieee80211_superg.c Mon Sep 28 00:51:24 2015
(r288317)
+++ head/sys/net80211/ieee80211_superg.c Mon Sep 28 00:59:07 2015
(r288318)
@@ -530,7 +530,6 @@ ieee80211_ff_age(struct ieee80211com *ic
{
struct mbuf *m, *head;
struct ieee80211_node *ni;
- struct ieee80211_tx_ampdu *tap;
#if 0
KASSERT(sq->head != NULL, ("stageq empty"));
@@ -541,11 +540,10 @@ ieee80211_ff_age(struct ieee80211com *ic
while ((m = sq->head) != NULL && M_AGE_GET(m) < quanta) {
int tid = WME_AC_TO_TID(M_WME_GETAC(m));
- /* clear tap ref to frame */
+ /* clear staging ref to frame */
ni = (struct ieee80211_node *) m->m_pkthdr.rcvif;
- tap = &ni->ni_tx_ampdu[tid];
- KASSERT(tap->txa_private == m, ("staging queue empty"));
- tap->txa_private = NULL;
+ KASSERT(ni->ni_tx_superg[tid] == m, ("staging queue empty"));
+ ni->ni_tx_superg[tid] = NULL;
sq->head = m->m_nextpkt;
sq->depth--;
@@ -658,7 +656,12 @@ ieee80211_ff_check(struct ieee80211_node
*/
IEEE80211_LOCK(ic);
tap = &ni->ni_tx_ampdu[WME_AC_TO_TID(pri)];
- mstaged = tap->txa_private; /* NB: we reuse AMPDU state */
+ mstaged = ni->ni_tx_superg[WME_AC_TO_TID(pri)];
+ /* XXX NOTE: reusing packet counter state from A-MPDU */
+ /*
+ * XXX NOTE: this means we're double-counting; it should just
+ * be done in ieee80211_output.c once for both superg and A-MPDU.
+ */
ieee80211_txampdu_count_packet(tap);
/*
@@ -676,6 +679,8 @@ ieee80211_ff_check(struct ieee80211_node
* If there is no frame to combine with and the pps is
* too low; then do not attempt to aggregate this frame.
*/
+ IEEE80211_DPRINTF(vap, IEEE80211_MSG_SUPERG,
+ "%s: staged: %p; pps: %d\n", __func__, mstaged,
ieee80211_txampdu_getpps(tap));
if (mstaged == NULL &&
ieee80211_txampdu_getpps(tap) < ieee80211_ffppsmin) {
IEEE80211_UNLOCK(ic);
@@ -698,7 +703,7 @@ ieee80211_ff_check(struct ieee80211_node
"%s: txtime %u exceeds txop limit %u\n",
__func__, txtime, limit);
- tap->txa_private = NULL;
+ ni->ni_tx_superg[WME_AC_TO_TID(pri)] = NULL;
if (mstaged != NULL)
stageq_remove(ic, sq, mstaged);
IEEE80211_UNLOCK(ic);
@@ -721,7 +726,7 @@ ieee80211_ff_check(struct ieee80211_node
* hold their node reference.
*/
if (mstaged != NULL) {
- tap->txa_private = NULL;
+ ni->ni_tx_superg[WME_AC_TO_TID(pri)] = NULL;
stageq_remove(ic, sq, mstaged);
IEEE80211_UNLOCK(ic);
@@ -739,9 +744,10 @@ ieee80211_ff_check(struct ieee80211_node
mstaged->m_nextpkt = m;
mstaged->m_flags |= M_FF; /* NB: mark for encap work */
} else {
- KASSERT(tap->txa_private == NULL,
- ("txa_private %p", tap->txa_private));
- tap->txa_private = m;
+ KASSERT(ni->ni_tx_superg[WME_AC_TO_TID(pri)]== NULL,
+ ("ni_tx_superg[]: %p",
+ ni->ni_tx_superg[WME_AC_TO_TID(pri)]));
+ ni->ni_tx_superg[WME_AC_TO_TID(pri)] = m;
stageq_add(ic, sq, m);
IEEE80211_UNLOCK(ic);
@@ -769,7 +775,6 @@ ieee80211_ff_node_cleanup(struct ieee802
{
struct ieee80211com *ic = ni->ni_ic;
struct ieee80211_superg *sg = ic->ic_superg;
- struct ieee80211_tx_ampdu *tap;
struct mbuf *m, *next_m, *head;
int tid;
@@ -777,11 +782,16 @@ ieee80211_ff_node_cleanup(struct ieee802
head = NULL;
for (tid = 0; tid < WME_NUM_TID; tid++) {
int ac = TID_TO_WME_AC(tid);
-
- tap = &ni->ni_tx_ampdu[tid];
- m = tap->txa_private;
+ /*
+ * XXX Initialise the packet counter.
+ *
+ * This may be double-work for 11n stations;
+ * but without it we never setup things.
+ */
+ ieee80211_txampdu_init_pps(&ni->ni_tx_ampdu[tid]);
+ m = ni->ni_tx_superg[tid];
if (m != NULL) {
- tap->txa_private = NULL;
+ ni->ni_tx_superg[tid] = NULL;
stageq_remove(ic, &sg->ff_stageq[ac], m);
m->m_nextpkt = head;
head = m;
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