RDS/IW+IB: Set recv ring low water mark to 1/2 full.

Currently the recv ring low water mark is 1/4 the depth. Performance measurements show that this limits iWARP throughput by flow controlling the rds-stress senders. Setting it to 1/2 seems to max the T3 performance. I tried even higher levels but that didn't help and it started to increase the rds thread cpu utilization. Signed-off-by: Steve Wise <[email protected]> Signed-off-by: Andy Grover <[email protected]> Signed-off-by: David S. Miller <[email protected]>
josf · Apr 10, 2009 · 5cd2fe6 · 5cd2fe6
1 parent a0c31fd
commit 5cd2fe6
Show file tree

Hide file tree

Showing 2 changed files with 2 additions and 2 deletions.
diff --git a/net/rds/ib_ring.c b/net/rds/ib_ring.c
@@ -137,7 +137,7 @@ int rds_ib_ring_empty(struct rds_ib_work_ring *ring)
 
 int rds_ib_ring_low(struct rds_ib_work_ring *ring)
 {
-	return __rds_ib_ring_used(ring) <= (ring->w_nr >> 2);
+	return __rds_ib_ring_used(ring) <= (ring->w_nr >> 1);
 }
 
 /*

diff --git a/net/rds/iw_ring.c b/net/rds/iw_ring.c
@@ -137,7 +137,7 @@ int rds_iw_ring_empty(struct rds_iw_work_ring *ring)
 
 int rds_iw_ring_low(struct rds_iw_work_ring *ring)
 {
-	return __rds_iw_ring_used(ring) <= (ring->w_nr >> 2);
+	return __rds_iw_ring_used(ring) <= (ring->w_nr >> 1);
 }
-Original file line number
+Diff line change
@@ Expand Up / @@ -137,7 +137,7 @@ int rds_ib_ring_empty(struct rds_ib_work_ring *ring) @@
     int rds_ib_ring_low(struct rds_ib_work_ring *ring)
     {
-    	return __rds_ib_ring_used(ring) <= (ring->w_nr >> 2);
+    	return __rds_ib_ring_used(ring) <= (ring->w_nr >> 1);
     }
     /*
@@ Expand Down @@