[dpdk-dev] examples/distributor: fix Rx thread logic for zero packets

Message ID 1468511325-15117-1-git-send-email-reshma.pattan@intel.com (mailing list archive)
State Accepted, archived
Headers

Commit Message

Pattan, Reshma July 14, 2016, 3:48 p.m. UTC
  From: Reshma Pattan <reshma.pattan@intel.com>

Zero packets can be returned by rte_eth_rx_burst() and
rte_distributor_returned_pkts() inside lcore_rx(), so
for zero packet scenario instead of proceeding to
next operations we should continue to the next iteration of the
loop to avoid unnecessary processing overhead which is causing
rx packets to be dropped and hence distributor failing to forward the
packets.

Fixes: 07db4a97 ("examples/distributor: new sample app")

Signed-off-by: Reshma Pattan <reshma.pattan@intel.com>
---
 examples/distributor/main.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)
  

Comments

De Lara Guarch, Pablo July 15, 2016, 9:59 a.m. UTC | #1
> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Reshma Pattan
> Sent: Thursday, July 14, 2016 4:49 PM
> To: dev@dpdk.org
> Cc: Pattan, Reshma
> Subject: [dpdk-dev] [PATCH] examples/distributor: fix Rx thread logic for zero
> packets
> 
> From: Reshma Pattan <reshma.pattan@intel.com>
> 
> Zero packets can be returned by rte_eth_rx_burst() and
> rte_distributor_returned_pkts() inside lcore_rx(), so
> for zero packet scenario instead of proceeding to
> next operations we should continue to the next iteration of the
> loop to avoid unnecessary processing overhead which is causing
> rx packets to be dropped and hence distributor failing to forward the
> packets.
> 
> Fixes: 07db4a97 ("examples/distributor: new sample app")
> 
> Signed-off-by: Reshma Pattan <reshma.pattan@intel.com>

Acked-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>
  
Thomas Monjalon July 15, 2016, 9:44 p.m. UTC | #2
> > Zero packets can be returned by rte_eth_rx_burst() and
> > rte_distributor_returned_pkts() inside lcore_rx(), so
> > for zero packet scenario instead of proceeding to
> > next operations we should continue to the next iteration of the
> > loop to avoid unnecessary processing overhead which is causing
> > rx packets to be dropped and hence distributor failing to forward the
> > packets.
> > 
> > Fixes: 07db4a97 ("examples/distributor: new sample app")
> > 
> > Signed-off-by: Reshma Pattan <reshma.pattan@intel.com>
> 
> Acked-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>

Applied, thanks
  

Patch

diff --git a/examples/distributor/main.c b/examples/distributor/main.c
index 24857f2..537cee1 100644
--- a/examples/distributor/main.c
+++ b/examples/distributor/main.c
@@ -221,14 +221,22 @@  lcore_rx(struct lcore_params *p)
 		struct rte_mbuf *bufs[BURST_SIZE*2];
 		const uint16_t nb_rx = rte_eth_rx_burst(port, 0, bufs,
 				BURST_SIZE);
+		if (unlikely(nb_rx == 0)) {
+			if (++port == nb_ports)
+				port = 0;
+			continue;
+		}
 		app_stats.rx.rx_pkts += nb_rx;
 
 		rte_distributor_process(d, bufs, nb_rx);
 		const uint16_t nb_ret = rte_distributor_returned_pkts(d,
 				bufs, BURST_SIZE*2);
 		app_stats.rx.returned_pkts += nb_ret;
-		if (unlikely(nb_ret == 0))
+		if (unlikely(nb_ret == 0)) {
+			if (++port == nb_ports)
+				port = 0;
 			continue;
+		}
 
 		uint16_t sent = rte_ring_enqueue_burst(r, (void *)bufs, nb_ret);
 		app_stats.rx.enqueued_pkts += sent;