[dpdk-dev] [PATCH] app/testpmd: fix Rx/Tx stats after clear stats command

["Wei Hu (Xavier)" <huwei013@chinasoftinc.com>]

From: Chengwen Feng <fengchengwen@huawei.com>

Currently, when running start/clear stats&xstats/stop command many times
based on testpmd application, there are incorrect RX/TX-packets stats as
below:
---------------------- Forward statistics for port 0  --------------
RX-packets: 18446744073709544808 RX-dropped: 0             ...ignore
TX-packets: 18446744073709536616 TX-dropped: 0             ...ignore
--------------------------------------------------------------------

The root cause as below:
1. The struct rte_port of testpmd.h has a member variable
   "struct rte_eth_stats stats" to store the last port statistics.
2. When runnig start command, it execute cmd_start_parsed ->
   start_packet_forwarding -> fwd_stats_reset, which call rte_eth_stats_get
   API function to save current port statistics.
3. When running stop command, it execute fwd_stats_display, which call
   rte_eth_stats_get to get current port statistics, and then minus last
   port statistics.
4. If we run clear stats or xstats after start command, then run stop,
   it may display above incorrect stats because the current Rx/Tx-packets
   is lower than the last saved RX/TX-packets(uint64_t overflow).

This patch fixes it by clearing last port statistics when executing
"clear stats/xstats" command.

Fixes: af75078fece3 ("first public release")
Cc: stable@dpdk.org

Signed-off-by: Chengwen Feng <fengchengwen@huawei.com>
Signed-off-by: Wei Hu (Xavier) <xavier.huwei@huawei.com>
---
 app/test-pmd/config.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/app/test-pmd/config.c b/app/test-pmd/config.c
index 72f25d152..0d2375607 100644
--- a/app/test-pmd/config.c
+++ b/app/test-pmd/config.c
@@ -234,10 +234,16 @@ nic_stats_display(portid_t port_id)
 void
 nic_stats_clear(portid_t port_id)
 {
+	struct rte_port *port;
+
 	if (port_id_is_invalid(port_id, ENABLED_WARN)) {
 		print_valid_ports();
 		return;
 	}
+
+	port = &ports[port_id];
+	/* clear last port statistics because eth stats reset */
+	memset(&port->stats, 0, sizeof(port->stats));
 	rte_eth_stats_reset(port_id);
 	printf("\n  NIC statistics for port %d cleared\n", port_id);
 }
@@ -308,12 +314,17 @@ nic_xstats_display(portid_t port_id)
 void
 nic_xstats_clear(portid_t port_id)
 {
+	struct rte_port *port;
 	int ret;
 
 	if (port_id_is_invalid(port_id, ENABLED_WARN)) {
 		print_valid_ports();
 		return;
 	}
+
+	port = &ports[port_id];
+	/* clear last port statistics because eth xstats(include stats) reset */
+	memset(&port->stats, 0, sizeof(port->stats));
 	ret = rte_eth_xstats_reset(port_id);
 	if (ret != 0) {
 		printf("%s: Error: failed to reset xstats (port %u): %s",
-- 
2.23.0