1. 13 Feb, 2018 39 commits
  2. 12 Feb, 2018 1 commit
    • Alexander Duyck's avatar
      i40e/i40evf: Add support for new mechanism of updating adaptive ITR · a0073a4b
      Alexander Duyck authored
      This patch replaces the existing mechanism for determining the correct
      value to program for adaptive ITR with yet another new and more
      complicated approach.
      
      The basic idea from a 30K foot view is that this new approach will push the
      Rx interrupt moderation up so that by default it starts in low latency and
      is gradually pushed up into a higher latency setup as long as doing so
      increases the number of packets processed, if the number of packets drops
      to 4 to 1 per packet we will reset and just base our ITR on the size of the
      packets being received. For Tx we leave it floating at a high interrupt
      delay and do not pull it down unless we start processing more than 112
      packets per interrupt. If we start exceeding that we will cut our interrupt
      rates in half until we are back below 112.
      
      The side effect of these patches are that we will be processing more
      packets per interrupt. This is both a good and a bad thing as it means we
      will not be blocking processing in the case of things like pktgen and XDP,
      but we will also be consuming a bit more CPU in the cases of things such as
      network throughput tests using netperf.
      
      One delta from this versus the ixgbe version of the changes is that I have
      made the interrupt moderation a bit more aggressive when we are in bulk
      mode by moving our "goldilocks zone" up from 48 to 96 to 56 to 112. The
      main motivation behind moving this is to address the fact that we need to
      update less frequently, and have more fine grained control due to the
      separate Tx and Rx ITR times.
      Signed-off-by: default avatarAlexander Duyck <alexander.h.duyck@intel.com>
      Tested-by: default avatarAndrew Bowers <andrewx.bowers@intel.com>
      Signed-off-by: default avatarJeff Kirsher <jeffrey.t.kirsher@intel.com>
      a0073a4b