[dpdk-dev] [PATCH v10 6/6] testpmd: use Tx preparation in csum engine

[Tomasz Kulasek <tomaszx.kulasek@intel.com>]

Removed pseudo header calculation for udp/tcp/tso packets from
application and used Tx preparation API for packet preparation and
verification.

Adding additional step to the csum engine costs about 3-4% of performance
drop, on my setup with ixgbe driver. It's caused mostly by the need
of reaccessing and modification of packet data.

Signed-off-by: Tomasz Kulasek <tomaszx.kulasek@intel.com>
---
 app/test-pmd/csumonly.c |   36 +++++++++++++-----------------------
 1 file changed, 13 insertions(+), 23 deletions(-)

diff --git a/app/test-pmd/csumonly.c b/app/test-pmd/csumonly.c
index 57e6ae2..6f33ae9 100644
--- a/app/test-pmd/csumonly.c
+++ b/app/test-pmd/csumonly.c
@@ -112,15 +112,6 @@ struct simple_gre_hdr {
 } __attribute__((__packed__));
 
 static uint16_t
-get_psd_sum(void *l3_hdr, uint16_t ethertype, uint64_t ol_flags)
-{
-	if (ethertype == _htons(ETHER_TYPE_IPv4))
-		return rte_ipv4_phdr_cksum(l3_hdr, ol_flags);
-	else /* assume ethertype == ETHER_TYPE_IPv6 */
-		return rte_ipv6_phdr_cksum(l3_hdr, ol_flags);
-}
-
-static uint16_t
 get_udptcp_checksum(void *l3_hdr, void *l4_hdr, uint16_t ethertype)
 {
 	if (ethertype == _htons(ETHER_TYPE_IPv4))
@@ -370,32 +361,24 @@ process_inner_cksums(void *l3_hdr, const struct testpmd_offload_info *info,
 		/* do not recalculate udp cksum if it was 0 */
 		if (udp_hdr->dgram_cksum != 0) {
 			udp_hdr->dgram_cksum = 0;
-			if (testpmd_ol_flags & TESTPMD_TX_OFFLOAD_UDP_CKSUM) {
+			if (testpmd_ol_flags & TESTPMD_TX_OFFLOAD_UDP_CKSUM)
 				ol_flags |= PKT_TX_UDP_CKSUM;
-				udp_hdr->dgram_cksum = get_psd_sum(l3_hdr,
-					info->ethertype, ol_flags);
-			} else {
+			else
 				udp_hdr->dgram_cksum =
 					get_udptcp_checksum(l3_hdr, udp_hdr,
 						info->ethertype);
-			}
 		}
 	} else if (info->l4_proto == IPPROTO_TCP) {
 		tcp_hdr = (struct tcp_hdr *)((char *)l3_hdr + info->l3_len);
 		tcp_hdr->cksum = 0;
-		if (tso_segsz) {
+		if (tso_segsz)
 			ol_flags |= PKT_TX_TCP_SEG;
-			tcp_hdr->cksum = get_psd_sum(l3_hdr, info->ethertype,
-				ol_flags);
-		} else if (testpmd_ol_flags & TESTPMD_TX_OFFLOAD_TCP_CKSUM) {
+		else if (testpmd_ol_flags & TESTPMD_TX_OFFLOAD_TCP_CKSUM)
 			ol_flags |= PKT_TX_TCP_CKSUM;
-			tcp_hdr->cksum = get_psd_sum(l3_hdr, info->ethertype,
-				ol_flags);
-		} else {
+		else
 			tcp_hdr->cksum =
 				get_udptcp_checksum(l3_hdr, tcp_hdr,
 					info->ethertype);
-		}
 	} else if (info->l4_proto == IPPROTO_SCTP) {
 		sctp_hdr = (struct sctp_hdr *)((char *)l3_hdr + info->l3_len);
 		sctp_hdr->cksum = 0;
@@ -648,6 +631,7 @@ pkt_burst_checksum_forward(struct fwd_stream *fs)
 	void *l3_hdr = NULL, *outer_l3_hdr = NULL; /* can be IPv4 or IPv6 */
 	uint16_t nb_rx;
 	uint16_t nb_tx;
+	uint16_t nb_prep;
 	uint16_t i;
 	uint64_t rx_ol_flags, tx_ol_flags;
 	uint16_t testpmd_ol_flags;
@@ -857,7 +841,13 @@ pkt_burst_checksum_forward(struct fwd_stream *fs)
 			printf("\n");
 		}
 	}
-	nb_tx = rte_eth_tx_burst(fs->tx_port, fs->tx_queue, pkts_burst, nb_rx);
+	nb_prep = rte_eth_tx_prep(fs->tx_port, fs->tx_queue, pkts_burst,
+				nb_rx);
+	if (nb_prep != nb_rx)
+		printf("Preparing packet burst to transmit failed: %s\n",
+				rte_strerror(rte_errno));
+
+	nb_tx = rte_eth_tx_burst(fs->tx_port, fs->tx_queue, pkts_burst, nb_prep);
 	/*
 	 * Retry if necessary
 	 */
-- 
1.7.9.5