[Intel-wired-lan] [PATCH] ixgbevf: add control of skipping PF link-status check

[Wang, Liang-min]

ixgbevf: add control of skipping PF link-status check

The ixgbevf link status check always triggers an interrupt on Physical Function (PF) driver because
it uses mailbox read to check PF link-status. For any Virtual Network Function (VNF) implementation
where periodical link-status check is needed, this interrupt per request becomes a significant
performance overhead. Therefore, this change uses the input parameter, autoneg_wait_to_complete, to
conditionally skip the PF link-status check. For scenarios where only quick Virtual Function (VF)
link status check is required, application could skip the PF interrupt by setting autoneg_wait_to_complete
to "0". For cases where deep link status check (include both PF and VF link status check) is required,
the application can set the autoneg_wait_to_complete to "1".

Signed-off-by: Liang-Min Wang<liang-min.wang at intel.com>
Reviewed-by: Jeffrey T Kirsher<jeffrey.t.kirsher at intel.com>
---
drivers/net/ethernet/intel/ixgbevf/vf.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/drivers/net/ethernet/intel/ixgbevf/vf.c b/drivers/net/ethernet/intel/ixgbevf/vf.c
index d5ce496..951d8aa 100644
--- a/drivers/net/ethernet/intel/ixgbevf/vf.c
+++ b/drivers/net/ethernet/intel/ixgbevf/vf.c
@@ -694,8 +694,18 @@ static s32 ixgbevf_check_mac_link_vf(struct ixgbe_hw *hw,
      case IXGBE_LINKS_SPEED_100_82599:
             *speed = IXGBE_LINK_SPEED_100_FULL;
             break;
+      default:
+             *speed = IXGBE_LINK_SPEED_UNKNOWN;
      }
+      if (!autoneg_wait_to_complete) {
+             if (*speed == IXGBE_LINK_SPEED_UNKNOWN)
+                    mac->get_link_status = true;
+             else
+                    mac->get_link_status = false;
+
+             goto out;
+      }
      /* if the read failed it could just be a mailbox collision, best wait
       * until we are called again and don't report an error
       */
--
2.4.11


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osuosl.org/pipermail/intel-wired-lan/attachments/20190612/3284e4b8/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0001-ixgbevf-add-control-of-skipping-PF-link-status-check.patch
Type: application/octet-stream
Size: 1962 bytes
Desc: 0001-ixgbevf-add-control-of-skipping-PF-link-status-check.patch
URL: <http://lists.osuosl.org/pipermail/intel-wired-lan/attachments/20190612/3284e4b8/attachment-0001.obj>