Double the number of descriptors we'll bundle into one tail bump when receiving. Empirical testing has shown that we reduce CPU utilization and don't appear to reduce throughput or packet rate. 32 seems to be the sweet spot, as it's half the default polling budget, so we'd essentially reduce from 4 tail writes when polling down to 2. Increasing this up to 64 appears to have negative impacts as it may become possible that we don't bump the tail each time we get polled, which could cause a long delay between returning descriptors to the hardware. Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> Tested-by: Andrew Bowers <andrewx.bowers@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>