From a1b87645d39d6aca7168e0863cd13b112efd102d Mon Sep 17 00:00:00 2001 From: Maxime Coquelin Date: Tue, 4 Oct 2016 14:05:24 +0200 Subject: [PATCH] app/testpmd: reset headroom after txonly packet allocation This patch fixes txonly raw packets allocations by resetting the available headroom. Indeed, some PMDs such as Virtio might prepend some data to the packet, resulting in mbuf's data_off field to be decremented each time the mbuf gets re-allocated. For Virtio PMD, it means that we use only single descriptors for the first times mbufs get allocated, as at some point there is not enough headroom to store the header. Other alternative would be use standard API to allocate the packets, which does reset the headroom, but the impact on performance is too big to consider this an option. Signed-off-by: Maxime Coquelin Acked-by: Olivier Matz --- app/test-pmd/txonly.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/app/test-pmd/txonly.c b/app/test-pmd/txonly.c index d2736b793c..8513a06206 100644 --- a/app/test-pmd/txonly.c +++ b/app/test-pmd/txonly.c @@ -222,6 +222,14 @@ pkt_burst_transmit(struct fwd_stream *fs) return; break; } + + /* + * Using raw alloc is good to improve performance, + * but some consumers may use the headroom and so + * decrement data_off. We need to make sure it is + * reset to default value. + */ + rte_pktmbuf_reset_headroom(pkt); pkt->data_len = tx_pkt_seg_lengths[0]; pkt_seg = pkt; if (tx_pkt_split == TX_PKT_SPLIT_RND) -- 2.20.1