app/testpmd: do not use TSO for small packets

Asking for TSO (TCP Segmentation Offload) on packets that are already
smaller than (headers + MSS) does not work, for instance on ixgbe.

Fix the csumonly engine to only set the TSO flag when a segmentation
offload is really required, i.e. when packet is large enough.

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
Acked-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>

diff --git a/app/test-pmd/csumonly.c b/app/test-pmd/csumonly.c
index dbd8dc4..d51d85a 100644 (file)
--- a/app/test-pmd/csumonly.c
+++ b/app/test-pmd/csumonly.c
@@ -102,6 +102,7 @@ struct testpmd_offload_info {
        uint8_t outer_l4_proto;
        uint16_t tso_segsz;
        uint16_t tunnel_tso_segsz;
+       uint32_t pkt_len;
 };
 
 /* simplified GRE header */
@@ -329,6 +330,21 @@ process_inner_cksums(void *l3_hdr, const struct testpmd_offload_info *info,
        struct tcp_hdr *tcp_hdr;
        struct sctp_hdr *sctp_hdr;
        uint64_t ol_flags = 0;
+       uint32_t max_pkt_len, tso_segsz = 0;
+
+       /* ensure packet is large enough to require tso */
+       if (!info->is_tunnel) {
+               max_pkt_len = info->l2_len + info->l3_len + info->l4_len +
+                       info->tso_segsz;
+               if (info->tunnel_tso_segsz != 0 && info->pkt_len > max_pkt_len)
+                       tso_segsz = info->tso_segsz;
+       } else {
+               max_pkt_len = info->outer_l2_len + info->outer_l3_len +
+                       info->l2_len + info->l3_len + info->l4_len +
+                       info->tunnel_tso_segsz;
+               if (info->tunnel_tso_segsz != 0 && info->pkt_len > max_pkt_len)
+                       tso_segsz = info->tunnel_tso_segsz;
+       }
 
        if (info->ethertype == _htons(ETHER_TYPE_IPv4)) {
                ipv4_hdr = l3_hdr;
@@ -369,8 +385,7 @@ process_inner_cksums(void *l3_hdr, const struct testpmd_offload_info *info,
        } else if (info->l4_proto == IPPROTO_TCP) {
                tcp_hdr = (struct tcp_hdr *)((char *)l3_hdr + info->l3_len);
                tcp_hdr->cksum = 0;
-               if ((info->is_tunnel && info->tunnel_tso_segsz != 0) ||
-                   (!info->is_tunnel && info->tso_segsz != 0)) {
+               if (tso_segsz) {
                        ol_flags |= PKT_TX_TCP_SEG;
                        tcp_hdr->cksum = get_psd_sum(l3_hdr, info->ethertype,
                                ol_flags);
@@ -679,6 +694,7 @@ pkt_burst_checksum_forward(struct fwd_stream *fs)
 
                m = pkts_burst[i];
                info.is_tunnel = 0;
+               info.pkt_len = rte_pktmbuf_pkt_len(m);
                tx_ol_flags = 0;
                rx_ol_flags = m->ol_flags;