net/af_packet: improve Tx statistics accuracy

Message ID 1570634949-26819-1-git-send-email-flavia.musatescu@intel.com
State Superseded
Delegated to: Ferruh Yigit
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Series
  • net/af_packet: improve Tx statistics accuracy
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Checks

Context Check Description
ci/iol-mellanox-Performance success Performance Testing PASS
ci/iol-intel-Performance success Performance Testing PASS
ci/iol-compilation success Compile Testing PASS
ci/Intel-compilation success Compilation OK
ci/checkpatch success coding style OK

Commit Message

Flavia Musatescu Oct. 9, 2019, 3:29 p.m.
When sendto call fails and ENOBUFS error is being set some of the
packets are actually successfully transmitted. There is no available
count of those packets, so in order to make the statistics more
accurate, all the previously enqueued packets will be considered
successful, even though this is not entirely correct.

Before:
   testpmd Tx statistics:
      TX-packets: 7529062   TX-errors: 3702150  TX-bytes:  451743720
   pktgen Rx statistics:
      Total Rx Pkts: 10700700

After:
   testpmd TX statistics:
      TX-packets: 11510625  TX-errors: 0        TX-bytes:  690637500
   pktgen Rx statistics:
      Total Rx Pkts: 10974307

Fixes: 74b7fc0a0ff1 ("net/af_packet: fix packet bytes counting")
Cc: ciwillia@brocade.com
Cc: stable@dpdk.org

Signed-off-by: Flavia Musatescu <flavia.musatescu@intel.com>
---
 drivers/net/af_packet/rte_eth_af_packet.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

Comments

Stephen Hemminger Oct. 9, 2019, 5:26 p.m. | #1
On Wed,  9 Oct 2019 16:29:09 +0100
Flavia Musatescu <flavia.musatescu@intel.com> wrote:

> +	if (sendto(pkt_q->sockfd, NULL, 0, MSG_DONTWAIT, NULL, 0) == -1 &&
> +			errno != ENOBUFS) {
> +		/* Error sending.
> +		 * When sendto call fails and ENOBUFS error is being set
> +		 * some of the packets are actually successfully transmitted.
> +		 * There is no available count of those packets, so in order
> +		 * to make the statistics more accurate, all of the previously
> +		 * enqueued packets will be considered successful, even though
> +		 * this is not entirely correct.
> +		 */

Agree with the change, but please keep only add a small code comment.
Long comments are a personal pet peeve, it also tends to standout as
"some different developer who had an issue left this comment"

Patch

diff --git a/drivers/net/af_packet/rte_eth_af_packet.c b/drivers/net/af_packet/rte_eth_af_packet.c
index 6df09f2..330fa75 100644
--- a/drivers/net/af_packet/rte_eth_af_packet.c
+++ b/drivers/net/af_packet/rte_eth_af_packet.c
@@ -244,8 +244,16 @@  eth_af_packet_tx(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
 	}
 
 	/* kick-off transmits */
-	if (sendto(pkt_q->sockfd, NULL, 0, MSG_DONTWAIT, NULL, 0) == -1) {
-		/* error sending -- no packets transmitted */
+	if (sendto(pkt_q->sockfd, NULL, 0, MSG_DONTWAIT, NULL, 0) == -1 &&
+			errno != ENOBUFS) {
+		/* Error sending.
+		 * When sendto call fails and ENOBUFS error is being set
+		 * some of the packets are actually successfully transmitted.
+		 * There is no available count of those packets, so in order
+		 * to make the statistics more accurate, all of the previously
+		 * enqueued packets will be considered successful, even though
+		 * this is not entirely correct.
+		 */
 		num_tx = 0;
 		num_tx_bytes = 0;
 	}