diff --git a/app/test-pmd/cmdline.c b/app/test-pmd/cmdline.c
index cd8c358..3224ce1 100644
--- a/app/test-pmd/cmdline.c
+++ b/app/test-pmd/cmdline.c
@@ -423,7 +423,7 @@ static void cmd_help_long_parsed(void *parsed_result,
 			"tso show (portid)"
 			"    Display the status of TCP Segmentation Offload.\n\n"
 
-			"gro (on|off) (port_id)"
+			"gro (heavymode|lightmode) (on|off) (port_id)\n"
 			"    Enable or disable Generic Receive Offload in"
 			" csum forwarding engine.\n\n"
 
@@ -431,6 +431,10 @@ static void cmd_help_long_parsed(void *parsed_result,
 			"    Set max flow number and max packet number per-flow"
 			" for GRO.\n\n"
 
+			"gro flush interval (num)\n"
+			"    Set the interval of flushing GROed packets from"
+			" reassembly tables.\n\n"
+
 			"set fwd (%s)\n"
 			"    Set packet forwarding mode.\n\n"
 
@@ -3853,6 +3857,7 @@ cmdline_parse_inst_t cmd_tunnel_tso_show = {
 struct cmd_gro_result {
 	cmdline_fixed_string_t cmd_keyword;
 	cmdline_fixed_string_t mode;
+	cmdline_fixed_string_t onoff;
 	uint8_t port_id;
 };
 
@@ -3864,7 +3869,7 @@ cmd_enable_gro_parsed(void *parsed_result,
 	struct cmd_gro_result *res;
 
 	res = parsed_result;
-	setup_gro(res->mode, res->port_id);
+	setup_gro(res->mode, res->onoff, res->port_id);
 }
 
 cmdline_parse_token_string_t cmd_gro_keyword =
@@ -3872,7 +3877,10 @@ cmdline_parse_token_string_t cmd_gro_keyword =
 			cmd_keyword, "gro");
 cmdline_parse_token_string_t cmd_gro_mode =
 	TOKEN_STRING_INITIALIZER(struct cmd_gro_result,
-			mode, "on#off");
+			mode, "heavymode#lightmode");
+cmdline_parse_token_string_t cmd_gro_onoff =
+	TOKEN_STRING_INITIALIZER(struct cmd_gro_result,
+			onoff, "on#off");
 cmdline_parse_token_num_t cmd_gro_pid =
 	TOKEN_NUM_INITIALIZER(struct cmd_gro_result,
 			port_id, UINT8);
@@ -3880,15 +3888,77 @@ cmdline_parse_token_num_t cmd_gro_pid =
 cmdline_parse_inst_t cmd_enable_gro = {
 	.f = cmd_enable_gro_parsed,
 	.data = NULL,
-	.help_str = "gro (on|off) (port_id)",
+	.help_str = "gro (heavymode|lightmode) (on|off) <port_id>",
 	.tokens = {
 		(void *)&cmd_gro_keyword,
 		(void *)&cmd_gro_mode,
+		(void *)&cmd_gro_onoff,
 		(void *)&cmd_gro_pid,
 		NULL,
 	},
 };
 
+/* *** SET FLUSH INTERVAL FOR THE HEAVYWEIGHT MODE GRO *** */
+struct cmd_gro_flush_result {
+	cmdline_fixed_string_t cmd_keyword;
+	cmdline_fixed_string_t cmd_flush;
+	cmdline_fixed_string_t cmd_interval;
+	uint32_t cmd_num;
+};
+
+static void
+cmd_gro_flush_parsed(void *parsed_result,
+		__attribute__((unused)) struct cmdline *cl,
+		__attribute__((unused)) void *data)
+{
+	struct cmd_gro_flush_result *res;
+
+	res = parsed_result;
+	if (test_done == 0) {
+		printf("Before set flushing interval for the heavyweight"
+				" mode GRO, please stop forwarding first\n");
+		return;
+	}
+
+	if (!strcmp(res->cmd_interval, "interval")) {
+		if (res->cmd_num > GRO_DEFAULT_FLUSH_INTERVAL) {
+			printf("The interval value should be in the range"
+					" of 0 to %u. Revert to the default"
+					" value %u\n",
+					GRO_MAX_FLUSH_INTERVAL,
+					GRO_DEFAULT_FLUSH_INTERVAL);
+			gro_flush_interval = GRO_DEFAULT_FLUSH_INTERVAL;
+		} else
+			gro_flush_interval = res->cmd_num;
+	}
+}
+
+cmdline_parse_token_string_t cmd_gro_flush_keyword =
+	TOKEN_STRING_INITIALIZER(struct cmd_gro_flush_result,
+			cmd_keyword, "gro");
+cmdline_parse_token_string_t cmd_gro_flush_flush =
+	TOKEN_STRING_INITIALIZER(struct cmd_gro_flush_result,
+			cmd_flush, "flush");
+cmdline_parse_token_string_t cmd_gro_flush_interval =
+	TOKEN_STRING_INITIALIZER(struct cmd_gro_flush_result,
+			cmd_interval, "interval");
+cmdline_parse_token_num_t cmd_gro_flush_num =
+	TOKEN_NUM_INITIALIZER(struct cmd_gro_flush_result,
+			cmd_num, UINT32);
+
+cmdline_parse_inst_t cmd_gro_flush = {
+	.f = cmd_gro_flush_parsed,
+	.data = NULL,
+	.help_str = "gro flush interval <num>",
+	.tokens = {
+		(void *)&cmd_gro_flush_keyword,
+		(void *)&cmd_gro_flush_flush,
+		(void *)&cmd_gro_flush_interval,
+		(void *)&cmd_gro_flush_num,
+		NULL,
+	},
+};
+
 /* *** SET MAX FLOW NUMBER AND ITEM NUM PER FLOW FOR GRO *** */
 struct cmd_gro_set_result {
 	cmdline_fixed_string_t gro;
@@ -14251,6 +14321,7 @@ cmdline_parse_ctx_t main_ctx[] = {
 	(cmdline_parse_inst_t *)&cmd_tunnel_tso_show,
 	(cmdline_parse_inst_t *)&cmd_enable_gro,
 	(cmdline_parse_inst_t *)&cmd_gro_set,
+	(cmdline_parse_inst_t *)&cmd_gro_flush,
 	(cmdline_parse_inst_t *)&cmd_link_flow_control_set,
 	(cmdline_parse_inst_t *)&cmd_link_flow_control_set_rx,
 	(cmdline_parse_inst_t *)&cmd_link_flow_control_set_tx,
diff --git a/app/test-pmd/config.c b/app/test-pmd/config.c
index 3ae3e1c..3a1321a 100644
--- a/app/test-pmd/config.c
+++ b/app/test-pmd/config.c
@@ -2420,7 +2420,7 @@ set_tx_pkt_segments(unsigned *seg_lengths, unsigned nb_segs)
 }
 
 void
-setup_gro(const char *mode, uint8_t port_id)
+setup_gro(const char *mode, const char *onoff, uint8_t port_id)
 {
 	if (!rte_eth_dev_is_valid_port(port_id)) {
 		printf("invalid port id %u\n", port_id);
@@ -2431,20 +2431,27 @@ setup_gro(const char *mode, uint8_t port_id)
 				" please stop forwarding first\n");
 		return;
 	}
-	if (strcmp(mode, "on") == 0) {
-		if (gro_ports[port_id].enable) {
-			printf("port %u has enabled GRO\n", port_id);
+	if (strcmp(onoff, "on") == 0) {
+		if (gro_ports[port_id].enable != 0) {
+			printf("port %u has enabled GRO. Please"
+					" disable GRO first\n", port_id);
 			return;
 		}
-		gro_ports[port_id].enable = 1;
-		gro_ports[port_id].param.gro_types = RTE_GRO_TCP_IPV4;
-
-		if (gro_ports[port_id].param.max_flow_num == 0)
-			gro_ports[port_id].param.max_flow_num =
-				GRO_DEFAULT_FLOW_NUM;
-		if (gro_ports[port_id].param.max_item_per_flow == 0)
-			gro_ports[port_id].param.max_item_per_flow =
-				GRO_DEFAULT_ITEM_NUM_PER_FLOW;
+		if (strcmp(mode, "heavymode") == 0)
+			gro_ports[port_id].enable = GRO_HEAVYMODE;
+		else {
+			gro_ports[port_id].enable = GRO_LIGHTMODE;
+			gro_ports[port_id].param.gro_types = RTE_GRO_TCP_IPV4;
+
+			if (gro_ports[port_id].param.max_flow_num == 0) {
+				gro_ports[port_id].param.max_flow_num =
+					GRO_DEFAULT_FLOW_NUM;
+			}
+			if (gro_ports[port_id].param.max_item_per_flow == 0) {
+				gro_ports[port_id].param.max_item_per_flow =
+					GRO_DEFAULT_ITEM_NUM_PER_FLOW;
+			}
+		}
 	} else {
 		if (gro_ports[port_id].enable == 0) {
 			printf("port %u has disabled GRO\n", port_id);
diff --git a/app/test-pmd/csumonly.c b/app/test-pmd/csumonly.c
index 90c8119..f9d818c 100644
--- a/app/test-pmd/csumonly.c
+++ b/app/test-pmd/csumonly.c
@@ -631,6 +631,9 @@ pkt_burst_checksum_forward(struct fwd_stream *fs)
 	struct rte_mbuf *m, *p;
 	struct ether_hdr *eth_hdr;
 	void *l3_hdr = NULL, *outer_l3_hdr = NULL; /* can be IPv4 or IPv6 */
+	void *gro_ctx;
+	uint16_t gro_pkts_num;
+	uint8_t gro_enable;
 	uint16_t nb_rx;
 	uint16_t nb_tx;
 	uint16_t nb_prep;
@@ -657,17 +660,33 @@ pkt_burst_checksum_forward(struct fwd_stream *fs)
 				 nb_pkt_per_burst);
 	if (unlikely(nb_rx == 0))
 		return;
-	if (unlikely(gro_ports[fs->rx_port].enable))
-		nb_rx = rte_gro_reassemble_burst(pkts_burst,
-				nb_rx,
-				&(gro_ports[fs->rx_port].param));
-
 #ifdef RTE_TEST_PMD_RECORD_BURST_STATS
 	fs->rx_burst_stats.pkt_burst_spread[nb_rx]++;
 #endif
 	fs->rx_packets += nb_rx;
 	rx_bad_ip_csum = 0;
 	rx_bad_l4_csum = 0;
+	gro_enable = gro_ports[fs->rx_port].enable;
+
+	if (unlikely(gro_enable == GRO_HEAVYMODE)) {
+		gro_ctx = current_fwd_lcore()->gro_ctx;
+		nb_rx = rte_gro_reassemble(pkts_burst, nb_rx, gro_ctx);
+
+		if (fs->gro_times++ >= gro_flush_interval) {
+			gro_pkts_num = rte_gro_get_pkt_count(gro_ctx);
+			if (gro_pkts_num > MAX_PKT_BURST - nb_rx)
+				gro_pkts_num = MAX_PKT_BURST - nb_rx;
+
+			nb_rx += rte_gro_timeout_flush(gro_ctx, 0,
+					gro_ports[fs->rx_port].param.gro_types,
+					&pkts_burst[nb_rx],
+					gro_pkts_num);
+			fs->gro_times = 0;
+		}
+	} else if (unlikely(gro_enable == GRO_LIGHTMODE)) {
+		nb_rx = rte_gro_reassemble_burst(pkts_burst, nb_rx,
+				&(gro_ports[fs->rx_port].param));
+	}
 
 	txp = &ports[fs->tx_port];
 	testpmd_ol_flags = txp->tx_ol_flags;
diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c
index 7d40139..f06c158 100644
--- a/app/test-pmd/testpmd.c
+++ b/app/test-pmd/testpmd.c
@@ -386,6 +386,7 @@ uint8_t bitrate_enabled;
 #endif
 
 struct gro_status gro_ports[RTE_MAX_ETHPORTS];
+uint32_t gro_flush_interval = GRO_DEFAULT_FLUSH_INTERVAL;
 
 /* Forward function declarations */
 static void map_port_queue_stats_mapping_registers(uint8_t pi, struct rte_port *port);
@@ -570,6 +571,7 @@ init_config(void)
 	unsigned int nb_mbuf_per_pool;
 	lcoreid_t  lc_id;
 	uint8_t port_per_socket[RTE_MAX_NUMA_NODES];
+	struct rte_gro_param gro_param;
 
 	memset(port_per_socket,0,RTE_MAX_NUMA_NODES);
 
@@ -671,6 +673,20 @@ init_config(void)
 		rte_exit(EXIT_FAILURE, "FAIL from init_fwd_streams()\n");
 
 	fwd_config_setup();
+
+	/* create a gro context for each lcore */
+	gro_param.gro_types = RTE_GRO_TCP_IPV4;
+	gro_param.max_flow_num = GRO_MAX_FLUSH_INTERVAL;
+	gro_param.max_item_per_flow = MAX_PKT_BURST;
+	for (lc_id = 0; lc_id < nb_lcores; lc_id++) {
+		gro_param.socket_id = rte_lcore_to_socket_id(
+				fwd_lcores_cpuids[lc_id]);
+		fwd_lcores[lc_id]->gro_ctx = rte_gro_ctx_create(&gro_param);
+		if (fwd_lcores[lc_id]->gro_ctx == NULL) {
+			rte_exit(EXIT_FAILURE,
+					"rte_gro_ctx_create() failed\n");
+		}
+	}
 }
 
 
@@ -1165,6 +1181,7 @@ start_packet_forwarding(int with_tx_first)
 		fwd_streams[sm_id]->fwd_dropped = 0;
 		fwd_streams[sm_id]->rx_bad_ip_csum = 0;
 		fwd_streams[sm_id]->rx_bad_l4_csum = 0;
+		fwd_streams[sm_id]->gro_times = 0;
 
 #ifdef RTE_TEST_PMD_RECORD_BURST_STATS
 		memset(&fwd_streams[sm_id]->rx_burst_stats, 0,
diff --git a/app/test-pmd/testpmd.h b/app/test-pmd/testpmd.h
index c9d7739..7c6c2eb 100644
--- a/app/test-pmd/testpmd.h
+++ b/app/test-pmd/testpmd.h
@@ -120,6 +120,7 @@ struct fwd_stream {
 	unsigned int fwd_dropped; /**< received packets not forwarded */
 	unsigned int rx_bad_ip_csum ; /**< received packets has bad ip checksum */
 	unsigned int rx_bad_l4_csum ; /**< received packets has bad l4 checksum */
+	unsigned int gro_times;	/**< reassembly times in heavyweight mode */
 #ifdef RTE_TEST_PMD_RECORD_CORE_CYCLES
 	uint64_t     core_cycles; /**< used for RX and TX processing */
 #endif
@@ -206,6 +207,7 @@ struct rte_port {
  */
 struct fwd_lcore {
 	struct rte_mempool *mbp; /**< The mbuf pool to use by this core */
+	void *gro_ctx;		/**< GRO context */
 	streamid_t stream_idx;   /**< index of 1st stream in "fwd_streams" */
 	streamid_t stream_nb;    /**< number of streams in "fwd_streams" */
 	lcoreid_t  cpuid_idx;    /**< index of logical core in CPU id table */
@@ -434,13 +436,21 @@ extern struct ether_addr peer_eth_addrs[RTE_MAX_ETHPORTS];
 extern uint32_t burst_tx_delay_time; /**< Burst tx delay time(us) for mac-retry. */
 extern uint32_t burst_tx_retry_num;  /**< Burst tx retry number for mac-retry. */
 
+#define GRO_HEAVYMODE 0x1
+#define GRO_LIGHTMODE 0x2
+
 #define GRO_DEFAULT_FLOW_NUM 4
 #define GRO_DEFAULT_ITEM_NUM_PER_FLOW DEF_PKT_BURST
+
+#define GRO_DEFAULT_FLUSH_INTERVAL 4
+#define GRO_MAX_FLUSH_INTERVAL 8
+
 struct gro_status {
 	struct rte_gro_param param;
 	uint8_t enable;
 };
 extern struct gro_status gro_ports[RTE_MAX_ETHPORTS];
+extern uint32_t gro_flush_interval;
 
 static inline unsigned int
 lcore_num(void)
@@ -640,7 +650,7 @@ void get_2tuple_filter(uint8_t port_id, uint16_t index);
 void get_5tuple_filter(uint8_t port_id, uint16_t index);
 int rx_queue_id_is_invalid(queueid_t rxq_id);
 int tx_queue_id_is_invalid(queueid_t txq_id);
-void setup_gro(const char *mode, uint8_t port_id);
+void setup_gro(const char *mode, const char *onoff, uint8_t port_id);
 
 /* Functions to manage the set of filtered Multicast MAC addresses */
 void mcast_addr_add(uint8_t port_id, struct ether_addr *mc_addr);
