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 <swise@opengridcomputing.com>
Signed-off-by: Andy Grover <andy.grover@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/rds/ib_ring.c b/net/rds/ib_ring.c
index 99a6cca..ff97e8e 100644
--- a/net/rds/ib_ring.c
+++ b/net/rds/ib_ring.c
@@ -137,7 +137,7 @@
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);
}
/*