Re: [PATCH 12/12] iwlwifi: Monitor and recover the aggregation TX flow failure

Andy Lutomirski <luto@xxxxxxx> · Fri, 12 Feb 2010 08:53:15 -0500

Reinette Chatre wrote:
From: Trieu 'Andrew' Nguyen <trieux.t.nguyen-ral2JQCrhuEAvxtiuMwx3w@xxxxxxxxxxxxxxxx>

This change monitors the tx statistics to detect the drop in throughput.
When the throughput drops, the ratio of the actual_ack_count and the expected_
ack_count also drops.  At the same time, the aggregated ba_timeout (the number
of ba timeout retries) also rises.  If the actual_ack_count/expected_ack_count
ratio is 0 and the number of ba timeout retries rises to 16, no tx packets
(tcp, udp, or ping - icmp) can be delivered.  The driver recovers from this
situation by reseting the uCode firmware.  If the actual_ack_count/expected_
ack_count ratio drops below 50% (but not 0) and the aggregated ba_timeout
retries just exceed 5 (but not 16), then the driver can reset the radio to
bring the throughput up.

Any chance this fixes big 2120?  Maybe I'm too optimistic, but I'll try 
to test it this afternoon.

http://bugzilla.intellinuxwireless.org/show_bug.cgi?id=2120

--Andy


Signed-off-by: Trieu 'Andrew' Nguyen <trieux.t.nguyen-ral2JQCrhuEAvxtiuMwx3w@xxxxxxxxxxxxxxxx>
Signed-off-by: Reinette Chatre <reinette.chatre-ral2JQCrhuEAvxtiuMwx3w@xxxxxxxxxxxxxxxx>
---
 drivers/net/wireless/iwlwifi/iwl-agn.c |   14 +++++++++-
 drivers/net/wireless/iwlwifi/iwl-dev.h |    3 ++
 drivers/net/wireless/iwlwifi/iwl-rx.c  |   46 ++++++++++++++++++++++++++++++++
 3 files changed, 62 insertions(+), 1 deletions(-)

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
index 31b156d..4157c6c 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
@@ -2941,10 +2941,21 @@ static int iwl_mac_ampdu_action(struct ieee80211_hw *hw,
 			return ret;
 	case IEEE80211_AMPDU_TX_START:
 		IWL_DEBUG_HT(priv, "start Tx\n");
-		return iwl_tx_agg_start(priv, sta->addr, tid, ssn);
+		ret = iwl_tx_agg_start(priv, sta->addr, tid, ssn);
+		if (ret == 0) {
+			priv->agg_tids_count++;
+			IWL_DEBUG_HT(priv, "priv->agg_tids_count = %u\n",
+				priv->agg_tids_count);
+		}
+		return ret;
 	case IEEE80211_AMPDU_TX_STOP:
 		IWL_DEBUG_HT(priv, "stop Tx\n");
 		ret = iwl_tx_agg_stop(priv, sta->addr, tid);
+		if ((ret == 0) && (priv->agg_tids_count > 0)) {
+			priv->agg_tids_count--;
+			IWL_DEBUG_HT(priv, "priv->agg_tids_count = %u\n",
+				priv->agg_tids_count);
+		}
 		if (test_bit(STATUS_EXIT_PENDING, &priv->status))
 			return 0;
 		else
@@ -3364,6 +3375,7 @@ static int iwl_init_drv(struct iwl_priv *priv)
 	priv->iw_mode = NL80211_IFTYPE_STATION;
 	priv->current_ht_config.smps = IEEE80211_SMPS_STATIC;
 	priv->missed_beacon_threshold = IWL_MISSED_BEACON_THRESHOLD_DEF;
+	priv->agg_tids_count = 0;
 
 	/* Choose which receivers/antennas to use */
 	if (priv->cfg->ops->hcmd->set_rxon_chain)
diff --git a/drivers/net/wireless/iwlwifi/iwl-dev.h b/drivers/net/wireless/iwlwifi/iwl-dev.h
index 71cf155..f81317d 100644
--- a/drivers/net/wireless/iwlwifi/iwl-dev.h
+++ b/drivers/net/wireless/iwlwifi/iwl-dev.h
@@ -1072,6 +1072,9 @@ struct iwl_priv {
 	/* storing the jiffies when the plcp error rate is received */
 	unsigned long plcp_jiffies;
 
+	/* reporting the number of tids has AGG on. 0 means no AGGREGATION */
+	u8 agg_tids_count;
+
 	/* force reset */
 	unsigned long last_force_reset_jiffies;
 
diff --git a/drivers/net/wireless/iwlwifi/iwl-rx.c b/drivers/net/wireless/iwlwifi/iwl-rx.c
index aba8f4c..fed554a 100644
--- a/drivers/net/wireless/iwlwifi/iwl-rx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-rx.c
@@ -616,6 +616,11 @@ static void iwl_accumulative_statistics(struct iwl_priv *priv,
 
 #define REG_RECALIB_PERIOD (60)
 
+/* the threshold ratio of actual_ack_cnt to expected_ack_cnt in percent */
+#define ACK_CNT_RATIO (50)
+#define BA_TIMEOUT_CNT (5)
+#define BA_TIMEOUT_MAX (16)
+
 #define PLCP_MSG "plcp_err exceeded %u, %u, %u, %u, %u, %d, %u mSecs\n"
 void iwl_rx_statistics(struct iwl_priv *priv,
 			      struct iwl_rx_mem_buffer *rxb)
@@ -625,6 +630,9 @@ void iwl_rx_statistics(struct iwl_priv *priv,
 	int combined_plcp_delta;
 	unsigned int plcp_msec;
 	unsigned long plcp_received_jiffies;
+	int actual_ack_cnt_delta;
+	int expected_ack_cnt_delta;
+	int ba_timeout_delta;
 
 	IWL_DEBUG_RX(priv, "Statistics notification received (%d vs %d).\n",
 		     (int)sizeof(priv->statistics),
@@ -639,6 +647,44 @@ void iwl_rx_statistics(struct iwl_priv *priv,
 #ifdef CONFIG_IWLWIFI_DEBUG
 	iwl_accumulative_statistics(priv, (__le32 *)&pkt->u.stats);
 #endif
+	actual_ack_cnt_delta = le32_to_cpu(pkt->u.stats.tx.actual_ack_cnt) -
+		le32_to_cpu(priv->statistics.tx.actual_ack_cnt);
+	expected_ack_cnt_delta = le32_to_cpu(
+			pkt->u.stats.tx.expected_ack_cnt) -
+		le32_to_cpu(priv->statistics.tx.expected_ack_cnt);
+	ba_timeout_delta = le32_to_cpu(
+			pkt->u.stats.tx.agg.ba_timeout) -
+		le32_to_cpu(priv->statistics.tx.agg.ba_timeout);
+	if ((priv->agg_tids_count > 0) &&
+		(expected_ack_cnt_delta > 0) &&
+		(((actual_ack_cnt_delta * 100) / expected_ack_cnt_delta) <
+			ACK_CNT_RATIO) &&
+		(ba_timeout_delta > BA_TIMEOUT_CNT)) {
+		IWL_DEBUG_RADIO(priv,
+			"actual_ack_cnt delta = %d, expected_ack_cnt = %d\n",
+			actual_ack_cnt_delta, expected_ack_cnt_delta);
+
+#ifdef CONFIG_IWLWIFI_DEBUG
+		IWL_DEBUG_RADIO(priv, "rx_detected_cnt delta = %d\n",
+			priv->delta_statistics.tx.rx_detected_cnt);
+		IWL_DEBUG_RADIO(priv,
+			"ack_or_ba_timeout_collision delta = %d\n",
+			priv->delta_statistics.tx.ack_or_ba_timeout_collision);
+#endif
+		IWL_DEBUG_RADIO(priv, "agg ba_timeout delta = %d\n",
+			ba_timeout_delta);
+		if ((actual_ack_cnt_delta == 0) &&
+			(ba_timeout_delta >=
+				BA_TIMEOUT_MAX)) {
+			IWL_DEBUG_RADIO(priv,
+				"call iwl_force_reset(IWL_FW_RESET)\n");
+			iwl_force_reset(priv, IWL_FW_RESET);
+		} else {
+			IWL_DEBUG_RADIO(priv,
+				"call iwl_force_reset(IWL_RF_RESET)\n");
+			iwl_force_reset(priv, IWL_RF_RESET);
+		}
+	}
 	/*
 	 * check for plcp_err and trigger radio reset if it exceeds
 	 * the plcp error threshold plcp_delta.

--
To unsubscribe from this list: send the line "unsubscribe linux-wireless" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




