dpdk/dpdk-16.04_patches/0019-enic-fix-Rx-queue-initialization-after-restarting-a-.patch

   1 From 8d336ba9cbcb4832b992201497afe07afcd4f2e1 Mon Sep 17 00:00:00 2001
   2 From: John Daley <johndale@cisco.com>
   3 Date: Fri, 1 Jul 2016 12:32:45 -0700
   4 Subject: [PATCH 19/25] enic: fix Rx queue initialization after restarting a
   5  device
   6
   7 If you stop then start a port that had already received some packets,
   8 the NIC could fetch discriptors from the wrong location. This could
   9 effectivly reduce the size of the Rx queue by a random amount and
  10 cause packet drop or reduced performance.
  11
  12 Reset the NIC fetch index to 0 when allocating and posting mbuf
  13 addresses to the NIC.
  14
  15 Fixes: 947d860c821f ("enic: improve Rx performance")
  16
  17 Signed-off-by: John Daley <johndale@cisco.com>
  18 Reviewed-by: Nelson Escobar <neescoba@cisco.com>
  19 ---
  20  drivers/net/enic/enic_main.c | 1 +
  21  1 file changed, 1 insertion(+)
  22
  23 diff --git a/drivers/net/enic/enic_main.c b/drivers/net/enic/enic_main.c
  24 index be17707..68532d3 100644
  25 --- a/drivers/net/enic/enic_main.c
  26 +++ b/drivers/net/enic/enic_main.c
  27 @@ -346,6 +346,7 @@ enic_alloc_rx_queue_mbufs(struct enic *enic, struct vnic_rq *rq)
  28         dev_debug(enic, "port=%u, qidx=%u, Write %u posted idx, %u sw held\n",
  29                 enic->port_id, rq->index, rq->posted_index, rq->rx_nb_hold);
  30         iowrite32(rq->posted_index, &rq->ctrl->posted_index);
  31 +       iowrite32(0, &rq->ctrl->fetch_index);
  32         rte_rmb();
  33
  34  //     printf("posted %d buffers to %s rq\n", rq->ring.desc_count,
  35 --
  36 2.7.0
  37