[PATCH] net/af_packet: cache align Rx/Tx structs

["Mattias Rönnblom" <mattias.ronnblom@ericsson.com>]

Cache align Rx and Tx queue struct to avoid false sharing.

RX struct happens to be 64 bytes on x86_64 already, so cache alignment
has no effect there, but it does on 32-bit ISAs.

TX struct is 56 bytes on x86_64.

Both structs keep counters, and in the RX case they are updated even
for empty polls.

Fixes: 364e08f2bbc0 ("af_packet: add PMD for AF_PACKET-based virtual devices")
Cc: stable@dpdk.org

Signed-off-by: Mattias Rönnblom <mattias.ronnblom@ericsson.com>
---
 drivers/net/af_packet/rte_eth_af_packet.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/af_packet/rte_eth_af_packet.c b/drivers/net/af_packet/rte_eth_af_packet.c
index 397a32db58..28aeb7d08e 100644
--- a/drivers/net/af_packet/rte_eth_af_packet.c
+++ b/drivers/net/af_packet/rte_eth_af_packet.c
@@ -6,6 +6,7 @@
  * All rights reserved.
  */
 
+#include <rte_common.h>
 #include <rte_string_fns.h>
 #include <rte_mbuf.h>
 #include <ethdev_driver.h>
@@ -53,7 +54,7 @@ struct pkt_rx_queue {
 
 	volatile unsigned long rx_pkts;
 	volatile unsigned long rx_bytes;
-};
+} __rte_cache_aligned;
 
 struct pkt_tx_queue {
 	int sockfd;
@@ -67,7 +68,7 @@ struct pkt_tx_queue {
 	volatile unsigned long tx_pkts;
 	volatile unsigned long err_pkts;
 	volatile unsigned long tx_bytes;
-};
+} __rte_cache_aligned;
 
 struct pmd_internals {
 	unsigned nb_queues;
-- 
2.34.1