[dpdk-dev] [PATCH 1/2] net/tap: remove redundant syscall on Tx

[Adrien Mazarguil]

Polling the Tx queue file descriptor before writing to it is not mandatory
since it is configured as non-blocking.

Signed-off-by: Adrien Mazarguil <adrien.mazarg...@6wind.com>
Acked-by: Pascal Mazon <pascal.ma...@6wind.com>
---
 drivers/net/tap/rte_eth_tap.c | 26 ++++++++------------------
 1 file changed, 8 insertions(+), 18 deletions(-)

diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c
index efc4426..c757a7c 100644
--- a/drivers/net/tap/rte_eth_tap.c
+++ b/drivers/net/tap/rte_eth_tap.c
@@ -43,7 +43,6 @@
 #include <sys/ioctl.h>
 #include <sys/mman.h>
 #include <unistd.h>
-#include <poll.h>
 #include <arpa/inet.h>
 #include <linux/if.h>
 #include <linux/if_tun.h>
@@ -242,7 +241,6 @@ pmd_tx_burst(void *queue, struct rte_mbuf **bufs, uint16_t 
nb_pkts)
 {
        struct rte_mbuf *mbuf;
        struct tx_queue *txq = queue;
-       struct pollfd pfd;
        uint16_t num_tx = 0;
        unsigned long num_tx_bytes = 0;
        int i, n;
@@ -250,26 +248,18 @@ pmd_tx_burst(void *queue, struct rte_mbuf **bufs, 
uint16_t nb_pkts)
        if (unlikely(nb_pkts == 0))
                return 0;
 
-       pfd.events = POLLOUT;
-       pfd.fd = txq->fd;
        for (i = 0; i < nb_pkts; i++) {
-               n = poll(&pfd, 1, 0);
-
+               /* copy the tx frame data */
+               mbuf = bufs[num_tx];
+               n = write(txq->fd,
+                         rte_pktmbuf_mtod(mbuf, void *),
+                         rte_pktmbuf_pkt_len(mbuf));
                if (n <= 0)
                        break;
 
-               if (pfd.revents & POLLOUT) {
-                       /* copy the tx frame data */
-                       mbuf = bufs[num_tx];
-                       n = write(pfd.fd, rte_pktmbuf_mtod(mbuf, void*),
-                                 rte_pktmbuf_pkt_len(mbuf));
-                       if (n <= 0)
-                               break;
-
-                       num_tx++;
-                       num_tx_bytes += mbuf->pkt_len;
-                       rte_pktmbuf_free(mbuf);
-               }
+               num_tx++;
+               num_tx_bytes += mbuf->pkt_len;
+               rte_pktmbuf_free(mbuf);
        }
 
        txq->stats.opackets += num_tx;
-- 
2.1.4