diff --git a/opensm/include/opensm/osm_base.h b/opensm/include/opensm/osm_base.h
index e0d6c66..16241ec 100644
--- a/opensm/include/opensm/osm_base.h
+++ b/opensm/include/opensm/osm_base.h
@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2004-2009 Voltaire, Inc. All rights reserved.
- * Copyright (c) 2002-2009 Mellanox Technologies LTD. All rights reserved.
+ * Copyright (c) 2002-2010 Mellanox Technologies LTD. All rights reserved.
  * Copyright (c) 1996-2003 Intel Corporation. All rights reserved.
  * Copyright (c) 2009 Sun Microsystems, Inc. All rights reserved.
  *
@@ -440,6 +440,30 @@ BEGIN_C_DECLS
 */
 #define OSM_DEFAULT_SMP_MAX_ON_WIRE 4
 /***********/
+/****d* OpenSM: Base/OSM_DEFAULT_SMP_RATE_MAX
+* NAME
+*	OSM_DEFAULT_SMP_RATE_MAX
+*
+* DESCRIPTION
+*	Specifies the default maximum number of outstanding rate based SMPs.
+*
+* SYNOPSIS
+*/
+#define OSM_DEFAULT_SMP_RATE_MAX 100
+/***********/
+/****d* OpenSM: Base/OSM_DEFAULT_SMP_RATE
+* NAME
+*	OSM_DEFAULT_SMP_RATE
+*
+* DESCRIPTION
+*	Specifies the default rate (in usec) for rate based SMPs.
+*	The default rate is 0. A value of 0 (or EVENT_NO_TIMEOUT)
+*	disables the rate based SMP mechanism.
+*
+* SYNOPSIS
+*/
+#define OSM_DEFAULT_SMP_RATE 0
+/***********/
 /****d* OpenSM: Base/OSM_SM_DEFAULT_QP0_RCV_SIZE
 * NAME
 *	OSM_SM_DEFAULT_QP0_RCV_SIZE
diff --git a/opensm/include/opensm/osm_subnet.h b/opensm/include/opensm/osm_subnet.h
index 4e8c862..49acf2d 100644
--- a/opensm/include/opensm/osm_subnet.h
+++ b/opensm/include/opensm/osm_subnet.h
@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2004-2009 Voltaire, Inc. All rights reserved.
- * Copyright (c) 2002-2009 Mellanox Technologies LTD. All rights reserved.
+ * Copyright (c) 2002-2010 Mellanox Technologies LTD. All rights reserved.
  * Copyright (c) 1996-2003 Intel Corporation. All rights reserved.
  * Copyright (c) 2008 Xsigo Systems Inc.  All rights reserved.
  * Copyright (c) 2009 System Fabric Works, Inc. All rights reserved.
@@ -149,6 +149,8 @@ typedef struct osm_subn_opt {
 	ib_net16_t m_key_lease_period;
 	uint32_t sweep_interval;
 	uint32_t max_wire_smps;
+	uint32_t max_rate_based_smps;
+	uint32_t rate_based_smp_usecs;
 	uint32_t transaction_timeout;
 	uint32_t transaction_retries;
 	uint8_t sm_priority;
@@ -264,6 +266,14 @@ typedef struct osm_subn_opt {
 *	max_wire_smps
 *		The maximum number of SMPs sent in parallel.  Default is 4.
 *
+*	max_rate_based_smps
+*		The maximum number of rate based SMPs allowed to be outstanding.
+*		Default is 1000.
+*
+*	rate_based_smp_usecs
+*		The wait time in usec for rate based SMPs.  Default is 0
+*		(disabled). 
+*
 *	transaction_timeout
 *		The maximum time in milliseconds allowed for a transaction
 *		to complete.  Default is 200.
diff --git a/opensm/include/opensm/osm_vl15intf.h b/opensm/include/opensm/osm_vl15intf.h
index 15ed56c..887733f 100644
--- a/opensm/include/opensm/osm_vl15intf.h
+++ b/opensm/include/opensm/osm_vl15intf.h
@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2004-2009 Voltaire, Inc. All rights reserved.
- * Copyright (c) 2002-2005 Mellanox Technologies LTD. All rights reserved.
+ * Copyright (c) 2002-2010 Mellanox Technologies LTD. All rights reserved.
  * Copyright (c) 1996-2003 Intel Corporation. All rights reserved.
  *
  * This software is available to you under a choice of one of two
@@ -117,6 +117,8 @@ typedef struct osm_vl15 {
 	osm_thread_state_t thread_state;
 	osm_vl15_state_t state;
 	uint32_t max_wire_smps;
+	uint32_t max_rate_based_smps;
+	uint32_t rate_based_smp_usecs;
 	cl_event_t signal;
 	cl_thread_t poller;
 	cl_qlist_t rfifo;
@@ -137,6 +139,12 @@ typedef struct osm_vl15 {
 *	max_wire_smps
 *		Maximum number of VL15 MADs allowed on the wire at one time.
 *
+*	max_rate_based_smps
+*		Maximum number of rate based SMPs allowed to be outstanding.
+*
+*	rate_based_smp_usecs
+*		Wait time in usec for rate based SMPs.
+*
 *	signal
 *		Event on which the poller sleeps.
 *
@@ -243,7 +251,9 @@ void osm_vl15_destroy(IN osm_vl15_t * p_vl15, IN struct osm_mad_pool *p_pool);
 */
 ib_api_status_t osm_vl15_init(IN osm_vl15_t * p_vl15, IN osm_vendor_t * p_vend,
 			      IN osm_log_t * p_log, IN osm_stats_t * p_stats,
-			      IN int32_t max_wire_smps);
+			      IN int32_t max_wire_smps,
+			      IN int32_t max_rate_based_smps,
+			      IN uint32_t rate_based_smp_usecs);
 /*
 * PARAMETERS
 *	p_vl15
@@ -261,6 +271,14 @@ ib_api_status_t osm_vl15_init(IN osm_vl15_t * p_vl15, IN osm_vendor_t * p_vend,
 *	max_wire_smps
 *		[in] Maximum number of MADs allowed on the wire at one time.
 *
+*	max_rate_based_smps
+*		[in] Maximum number of rate based SMPs allowed to be
+*		     outstanding.
+*
+*	rate_based_smp_usecs
+*		[in] Wait time in usec for rate based SMPs.
+*
+*
 * RETURN VALUES
 *	IB_SUCCESS if the VL15 object was initialized successfully.
 *
diff --git a/opensm/opensm/main.c b/opensm/opensm/main.c
index 0093aa7..83b94b0 100644
--- a/opensm/opensm/main.c
+++ b/opensm/opensm/main.c
@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2004-2009 Voltaire, Inc. All rights reserved.
- * Copyright (c) 2002-2009 Mellanox Technologies LTD. All rights reserved.
+ * Copyright (c) 2002-2010 Mellanox Technologies LTD. All rights reserved.
  * Copyright (c) 1996-2003 Intel Corporation. All rights reserved.
  * Copyright (c) 2009 HNR Consulting. All rights reserved.
  * Copyright (c) 2009 System Fabric Works, Inc. All rights reserved.
@@ -743,8 +743,8 @@ int main(int argc, char *argv[])
 		case 'n':
 			opt.max_wire_smps = strtoul(optarg, NULL, 0);
 			if (opt.max_wire_smps == 0 ||
-			    opt.max_wire_smps > 0x7FFFFFFF)
-				opt.max_wire_smps = 0x7FFFFFFF;
+			    opt.max_wire_smps > 0x3FFFFFFF)
+				opt.max_wire_smps = 0x3FFFFFFF;
 			printf(" Max wire smp's = %d\n", opt.max_wire_smps);
 			break;
 
diff --git a/opensm/opensm/osm_opensm.c b/opensm/opensm/osm_opensm.c
index d0f39da..bf2014f 100644
--- a/opensm/opensm/osm_opensm.c
+++ b/opensm/opensm/osm_opensm.c
@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2004-2009 Voltaire, Inc. All rights reserved.
- * Copyright (c) 2002-2006 Mellanox Technologies LTD. All rights reserved.
+ * Copyright (c) 2002-2010 Mellanox Technologies LTD. All rights reserved.
  * Copyright (c) 1996-2003 Intel Corporation. All rights reserved.
  *
  * This software is available to you under a choice of one of two
@@ -392,7 +392,9 @@ ib_api_status_t osm_opensm_init(IN osm_opensm_t * p_osm,
 
 	status = osm_vl15_init(&p_osm->vl15, p_osm->p_vendor,
 			       &p_osm->log, &p_osm->stats,
-			       p_opt->max_wire_smps);
+			       p_opt->max_wire_smps,
+			       p_opt->max_rate_based_smps,
+			       p_opt->rate_based_smp_usecs);
 	if (status != IB_SUCCESS)
 		goto Exit;
 
diff --git a/opensm/opensm/osm_subnet.c b/opensm/opensm/osm_subnet.c
index ba2c812..6aaf6dc 100644
--- a/opensm/opensm/osm_subnet.c
+++ b/opensm/opensm/osm_subnet.c
@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2004-2009 Voltaire, Inc. All rights reserved.
- * Copyright (c) 2002-2009 Mellanox Technologies LTD. All rights reserved.
+ * Copyright (c) 2002-2010 Mellanox Technologies LTD. All rights reserved.
  * Copyright (c) 1996-2003 Intel Corporation. All rights reserved.
  * Copyright (c) 2008 Xsigo Systems Inc.  All rights reserved.
  * Copyright (c) 2009 System Fabric Works, Inc. All rights reserved.
@@ -297,6 +297,8 @@ static const opt_rec_t opt_tbl[] = {
 	{ "m_key_lease_period", OPT_OFFSET(m_key_lease_period), opts_parse_net16, NULL, 1 },
 	{ "sweep_interval", OPT_OFFSET(sweep_interval), opts_parse_uint32, NULL, 1 },
 	{ "max_wire_smps", OPT_OFFSET(max_wire_smps), opts_parse_uint32, NULL, 1 },
+	{ "max_rate_based_smps", OPT_OFFSET(max_rate_based_smps), opts_parse_uint32, NULL, 1 },
+	{ "rate_based_smp_usecs", OPT_OFFSET(rate_based_smp_usecs), opts_parse_uint32, NULL, 1 },
 	{ "console", OPT_OFFSET(console), opts_parse_charp, NULL, 0 },
 	{ "console_port", OPT_OFFSET(console_port), opts_parse_uint16, NULL, 0 },
 	{ "transaction_timeout", OPT_OFFSET(transaction_timeout), opts_parse_uint32, NULL, 0 },
@@ -670,6 +672,8 @@ void osm_subn_set_default_opt(IN osm_subn_opt_t * p_opt)
 	p_opt->m_key_lease_period = 0;
 	p_opt->sweep_interval = OSM_DEFAULT_SWEEP_INTERVAL_SECS;
 	p_opt->max_wire_smps = OSM_DEFAULT_SMP_MAX_ON_WIRE;
+	p_opt->max_rate_based_smps = OSM_DEFAULT_SMP_RATE_MAX;
+	p_opt->rate_based_smp_usecs = OSM_DEFAULT_SMP_RATE;
 	p_opt->console = strdup(OSM_DEFAULT_CONSOLE);
 	p_opt->console_port = OSM_DEFAULT_CONSOLE_PORT;
 	p_opt->transaction_timeout = OSM_DEFAULT_TRANS_TIMEOUT_MILLISEC;
@@ -1066,14 +1070,22 @@ int osm_subn_verify_config(IN osm_subn_opt_t * p_opts)
 	}
 
 	if (p_opts->max_wire_smps == 0)
-		p_opts->max_wire_smps = 0x7FFFFFFF;
-	else if (p_opts->max_wire_smps > 0x7FFFFFFF) {
+		p_opts->max_wire_smps = 0x3FFFFFFF;
+	else if (p_opts->max_wire_smps > 0x3FFFFFFF) {
 		log_report(" Invalid Cached Option Value: max_wire_smps = %u,"
 			   " Using Default: %u\n",
 			   p_opts->max_wire_smps, OSM_DEFAULT_SMP_MAX_ON_WIRE);
 		p_opts->max_wire_smps = OSM_DEFAULT_SMP_MAX_ON_WIRE;
 	}
 
+	if (p_opts->max_rate_based_smps > 0x3FFFFFFF) {
+		log_report(" Invalid Cached Option Value:"
+			   " max_rate_based_smps = %u, Using Default: %u",
+			   p_opts->max_rate_based_smps,
+			   OSM_DEFAULT_SMP_RATE_MAX);
+		p_opts->max_rate_based_smps = OSM_DEFAULT_SMP_RATE_MAX;
+	}
+
 	if (strcmp(p_opts->console, OSM_DISABLE_CONSOLE)
 	    && strcmp(p_opts->console, OSM_LOCAL_CONSOLE)
 #ifdef ENABLE_OSM_CONSOLE_SOCKET
@@ -1482,6 +1494,11 @@ int osm_subn_output_conf(FILE *out, IN osm_subn_opt_t * p_opts)
 		"#\n# TIMING AND THREADING OPTIONS\n#\n"
 		"# Maximum number of SMPs sent in parallel\n"
 		"max_wire_smps %u\n\n"
+		"# Maximum number of rate based SMPs allowed to be outstanding\n"
+		"max_rate_based_smps %u\n\n"
+		"# The rate in [usec] at which rate based SMPs are sent\n"
+		"# A value of 0 disables the rate based SMP mechanism\n"
+		"rate_based_smp_usecs %u\n\n"
 		"# The maximum time in [msec] allowed for a transaction to complete\n"
 		"transaction_timeout %u\n\n"
 		"# The maximum number of retries allowed for a transaction to complete\n"
@@ -1494,6 +1511,8 @@ int osm_subn_output_conf(FILE *out, IN osm_subn_opt_t * p_opts)
 		"# Use a single thread for handling SA queries\n"
 		"single_thread %s\n\n",
 		p_opts->max_wire_smps,
+		p_opts->max_rate_based_smps,
+		p_opts->rate_based_smp_usecs,
 		p_opts->transaction_timeout,
 		p_opts->transaction_retries,
 		p_opts->max_msg_fifo_timeout,
diff --git a/opensm/opensm/osm_vl15intf.c b/opensm/opensm/osm_vl15intf.c
index ff9e4db..fdcca44 100644
--- a/opensm/opensm/osm_vl15intf.c
+++ b/opensm/opensm/osm_vl15intf.c
@@ -1,7 +1,7 @@
 /*
  * Copyright (c) 2009 Sun Microsystems, Inc. All rights reserved.
  * Copyright (c) 2004-2009 Voltaire, Inc. All rights reserved.
- * Copyright (c) 2002-2006,2009 Mellanox Technologies LTD. All rights reserved.
+ * Copyright (c) 2002-2010 Mellanox Technologies LTD. All rights reserved.
  * Copyright (c) 1996-2003 Intel Corporation. All rights reserved.
  *
  * This software is available to you under a choice of one of two
@@ -113,6 +113,8 @@ static void vl15_poller(IN void *p_ptr)
 	osm_madw_t *p_madw;
 	osm_vl15_t *p_vl = p_ptr;
 	cl_qlist_t *p_fifo;
+	int32_t max_smps = p_vl->max_wire_smps;
+	int32_t max_smps2 = p_vl->max_wire_smps + p_vl->max_rate_based_smps;
 
 	OSM_LOG_ENTER(p_vl->p_log);
 
@@ -155,17 +157,22 @@ static void vl15_poller(IN void *p_ptr)
 			status = cl_event_wait_on(&p_vl->signal,
 						  EVENT_NO_TIMEOUT, TRUE);
 
-		while (p_vl->p_stats->qp0_mads_outstanding_on_wire >=
-		       (int32_t) p_vl->max_wire_smps &&
+		while (p_vl->p_stats->qp0_mads_outstanding_on_wire >= max_smps &&
 		       p_vl->thread_state == OSM_THREAD_STATE_RUN) {
 			status = cl_event_wait_on(&p_vl->signal,
-						  EVENT_NO_TIMEOUT, TRUE);
-			if (status != CL_SUCCESS) {
+						  p_vl->rate_based_smp_usecs,
+						  TRUE);
+			if (status == CL_TIMEOUT) {
+				if (max_smps < max_smps2)
+					max_smps++;
+				break;
+			} else if (status != CL_SUCCESS) {
 				OSM_LOG(p_vl->p_log, OSM_LOG_ERROR, "ERR 3E02: "
 					"Event wait failed (%s)\n",
 					CL_STATUS_MSG(status));
 				break;
 			}
+			max_smps = p_vl->max_wire_smps;
 		}
 	}
 
@@ -236,7 +243,9 @@ void osm_vl15_destroy(IN osm_vl15_t * p_vl, IN struct osm_mad_pool *p_pool)
 
 ib_api_status_t osm_vl15_init(IN osm_vl15_t * p_vl, IN osm_vendor_t * p_vend,
 			      IN osm_log_t * p_log, IN osm_stats_t * p_stats,
-			      IN int32_t max_wire_smps)
+			      IN int32_t max_wire_smps,
+			      IN int32_t max_rate_based_smps,
+			      IN uint32_t rate_based_smp_usecs)
 {
 	ib_api_status_t status = IB_SUCCESS;
 
@@ -246,6 +255,10 @@ ib_api_status_t osm_vl15_init(IN osm_vl15_t * p_vl, IN osm_vendor_t * p_vend,
 	p_vl->p_log = p_log;
 	p_vl->p_stats = p_stats;
 	p_vl->max_wire_smps = max_wire_smps;
+	p_vl->max_rate_based_smps = rate_based_smp_usecs && max_rate_based_smps ?
+				    max_rate_based_smps : 0;
+	p_vl->rate_based_smp_usecs = rate_based_smp_usecs && max_rate_based_smps ?
+				     rate_based_smp_usecs : EVENT_NO_TIMEOUT;
 
 	status = cl_event_init(&p_vl->signal, FALSE);
 	if (status != IB_SUCCESS)
