From: Simon Wilkinson <sxw@your-file-system.com>
Date: Mon, 25 Oct 2010 09:14:12 +0000 (+0100)
Subject: rx: Don't let timeouts force fast recovery
X-Git-Tag: upstream/1.8.0_pre1^2~4617
X-Git-Url: https://git.michaelhowe.org/gitweb/?a=commitdiff_plain;h=36e2d13b55085c996d38b30d003296c602ef8ee3;p=packages%2Fo%2Fopenafs.git

rx: Don't let timeouts force fast recovery

The current RX implementation goes into fast recovery whenever a
timeout occurs. This is incredibly wasteful, particularly on fast
connections. So, remove this in favour of TCP style behaviour.

Change-Id: I7afc08b69e7e1df80a38ac731af57ce91072a184
Reviewed-on: http://gerrit.openafs.org/3138
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Tested-by: Derrick Brashear <shadow@dementia.org>
Reviewed-by: Derrick Brashear <shadow@dementia.org>
---

diff --git a/src/rx/rx.c b/src/rx/rx.c
index a7d1c0039..773c75509 100644
--- a/src/rx/rx.c
+++ b/src/rx/rx.c
@@ -5638,7 +5638,6 @@ rxi_Start(struct rxevent *event,
 
     struct rx_packet *p;
     struct rx_packet *nxp;	/* Next pointer for queue_Scan */
-    struct rx_peer *peer = call->conn->peer;
     struct clock now, usenow, retryTime;
     int haveEvent;
     int nXmitPackets;
@@ -5657,53 +5656,8 @@ rxi_Start(struct rxevent *event,
 	    /* Nothing to do */
 	    return;
 	}
-	/* Timeouts trigger congestion recovery */
-#ifdef  AFS_GLOBAL_RXLOCK_KERNEL
-	if (call->flags & RX_CALL_FAST_RECOVER_WAIT) {
-	    /* someone else is waiting to start recovery */
-	    return;
-	}
-	call->flags |= RX_CALL_FAST_RECOVER_WAIT;
-	rxi_WaitforTQBusy(call);
-#endif /* AFS_GLOBAL_RXLOCK_KERNEL */
-	call->flags &= ~RX_CALL_FAST_RECOVER_WAIT;
-#ifdef	AFS_GLOBAL_RXLOCK_KERNEL
-        if (call->error) {
-            if (rx_stats_active)
-                rx_atomic_inc(&rx_tq_debug.rxi_start_in_error);
-            return;
-        }
-#endif
-        call->flags |= RX_CALL_FAST_RECOVER;
-
-        if (peer->maxDgramPackets > 1) {
-            call->MTU = RX_JUMBOBUFFERSIZE + RX_HEADER_SIZE;
-        } else {
-            call->MTU = MIN(peer->natMTU, peer->maxMTU);
-        }
-        call->ssthresh = MAX(4, MIN((int)call->cwind, (int)call->twind)) >> 1;
-        call->nDgramPackets = 1;
-        call->cwind = 1;
-        call->nextCwind = 1;
-        call->nAcks = 0;
-        call->nNacks = 0;
-        MUTEX_ENTER(&peer->peer_lock);
-        peer->MTU = call->MTU;
-        peer->cwind = call->cwind;
-        peer->nDgramPackets = 1;
-        peer->congestSeq++;
-        call->congestSeq = peer->congestSeq;
-        MUTEX_EXIT(&peer->peer_lock);
-        /* Clear retry times on packets. Otherwise, it's possible for
-         * some packets in the queue to force resends at rates faster
-         * than recovery rates.
-         */
-        for (queue_Scan(&call->tq, p, nxp, rx_packet)) {
-            if (!(p->flags & RX_PKTFLAG_ACKED)) {
-                clock_Zero(&p->retryTime);
-            }
-        }
     }
+
     if (call->error) {
 #ifdef	AFS_GLOBAL_RXLOCK_KERNEL
         if (rx_stats_active)