svn commit: r361118 - head/sys/dev/ath/ath_rate/sample

[Adrian Chadd]

Author: adrian
Date: Sat May 16 21:59:41 2020
New Revision: 361118
URL: https://svnweb.freebsd.org/changeset/base/361118

Log:
  [ath_rate_sample] Fix correct status when completing frames with short failures.
  
  My preivous logic was a bit wrong.  This caused transmissions that failed due
  to a mix of short and long retries to count intermediate rates as OK if the
  LONG retry count indicated some retries had made it to this intermediate rate,
  but the SHORT retry count was the one that caused the whole transmit to fail.
  
  Now status is passed in again - and this is the status for the whole transmission -
  and then update_stats() does some quick math to see if the current transmission
  series hit its long retry count or not before updating things as a success
  or failure.

Modified:
  head/sys/dev/ath/ath_rate/sample/sample.c

Modified: head/sys/dev/ath/ath_rate/sample/sample.c
==============================================================================
--- head/sys/dev/ath/ath_rate/sample/sample.c	Sat May 16 19:38:58 2020	(r361117)
+++ head/sys/dev/ath/ath_rate/sample/sample.c	Sat May 16 21:59:41 2020	(r361118)
@@ -933,6 +933,18 @@ ath_rate_setupxtxdesc(struct ath_softc *sc, struct ath
 	    s3code, sched->t3);		/* series 3 */
 }
 
+/*
+ * Update the current statistics.
+ *
+ * Note that status is for the FINAL transmit status, not this
+ * particular attempt.  So, check if tries > tries0 and if so
+ * assume this status failed.
+ *
+ * This is important because some failures are due to both
+ * short AND long retries; if the final issue was a short
+ * retry failure then we still want to account for the
+ * bad long retry attempts.
+ */
 static void
 update_stats(struct ath_softc *sc, struct ath_node *an, 
 		  int frame_size,
@@ -947,7 +959,7 @@ update_stats(struct ath_softc *sc, struct ath_node *an
 #endif
 	const int size_bin = size_to_bin(frame_size);
 	const int size = bin_to_size(size_bin);
-	int tt, tries_so_far;
+	int tt;
 	int is_ht40 = (an->an_node.ni_chw == 40);
 	int pct;
 
@@ -955,6 +967,15 @@ update_stats(struct ath_softc *sc, struct ath_node *an
 		return;
 
 	/*
+	 * Treat long retries as us exceeding retries, even
+	 * if the eventual attempt at some other MRR schedule
+	 * succeeded.
+	 */
+	if (tries > tries0) {
+		status = HAL_TXERR_XRETRY;
+	}
+
+	/*
 	 * If status is FAIL then we treat all frames as bad.
 	 * This better accurately tracks EWMA and average TX time
 	 * because even if the eventual transmission succeeded,
@@ -971,7 +992,6 @@ update_stats(struct ath_softc *sc, struct ath_node *an
 	 */
 	tt = calc_usecs_unicast_packet(sc, size, rix0,
 	    0 /* short_tries */, MIN(tries0, tries) - 1, is_ht40);
-	tries_so_far = tries0;
 
 	if (sn->stats[size_bin][rix0].total_packets < ssc->smoothing_minpackets) {
 		/* just average the first few packets */
@@ -1194,7 +1214,7 @@ ath_rate_tx_complete(struct ath_softc *sc, struct ath_
 			update_stats(sc, an, frame_size,
 				     rc[0].rix, rc[0].tries,
 				     short_tries, long_tries,
-				     long_tries > rc[0].tries,
+				     status,
 				     nframes, nbad);
 			long_tries -= rc[0].tries;
 		}
@@ -1203,7 +1223,7 @@ ath_rate_tx_complete(struct ath_softc *sc, struct ath_
 			update_stats(sc, an, frame_size,
 				     rc[1].rix, rc[1].tries,
 				     short_tries, long_tries,
-				     long_tries > rc[1].tries,
+				     status,
 				     nframes, nbad);
 			long_tries -= rc[1].tries;
 		}
@@ -1212,7 +1232,7 @@ ath_rate_tx_complete(struct ath_softc *sc, struct ath_
 			update_stats(sc, an, frame_size,
 				     rc[2].rix, rc[2].tries,
 				     short_tries, long_tries,
-				     long_tries > rc[2].tries,
+				     status,
 				     nframes, nbad);
 			long_tries -= rc[2].tries;
 		}
@@ -1221,7 +1241,7 @@ ath_rate_tx_complete(struct ath_softc *sc, struct ath_
 			update_stats(sc, an, frame_size,
 				     rc[3].rix, rc[3].tries,
 				     short_tries, long_tries,
-				     long_tries > rc[3].tries,
+				     status,
 				     nframes, nbad);
 		}
 	}