[PATCH v3] 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.

The 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.

The TX struct is 56 bytes on x86_64.

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

v3: Move __rte_cache_aligned directive to a MSVC-compatible location.

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..6b7b16f348 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>
@@ -39,7 +40,7 @@
 #define DFLT_FRAME_SIZE		(1 << 11)
 #define DFLT_FRAME_COUNT	(1 << 9)
 
-struct pkt_rx_queue {
+struct __rte_cache_aligned pkt_rx_queue {
 	int sockfd;
 
 	struct iovec *rd;
@@ -55,7 +56,7 @@ struct pkt_rx_queue {
 	volatile unsigned long rx_bytes;
 };
 
-struct pkt_tx_queue {
+struct __rte_cache_aligned pkt_tx_queue {
 	int sockfd;
 	unsigned int frame_data_size;
 
-- 
2.34.1