> From: Intel-wired-lan <intel-wired-lan-bounces@xxxxxxxxxx> On Behalf Of > Björn Töpel > Sent: Tuesday, August 25, 2020 4:36 AM > To: intel-wired-lan@xxxxxxxxxxxxxxxx > Cc: netdev@xxxxxxxxxxxxxxx; bpf@xxxxxxxxxxxxxxx; Topel, Bjorn > <bjorn.topel@xxxxxxxxx>; Karlsson, Magnus <magnus.karlsson@xxxxxxxxx>; > kuba@xxxxxxxxxx > Subject: [Intel-wired-lan] [PATCH net-next v2 2/3] i40e: use 16B HW > descriptors instead of 32B > > From: Björn Töpel <bjorn.topel@xxxxxxxxx> > > The i40e NIC supports two flavors of HW descriptors, 16 and 32 > byte. The latter has, obviously, room for more offloading > information. However, the only fields of the 32B HW descriptor that is > being used by the driver, is also available in the 16B descriptor. > > In other words; Reading and writing 32 bytes instead of 16 byte is a > waste of bus bandwidth. > > This commit starts using 16 byte descriptors instead of 32 byte > descriptors. > > For AF_XDP the rx_drop benchmark was improved by 2%. > > Signed-off-by: Björn Töpel <bjorn.topel@xxxxxxxxx> > --- > drivers/net/ethernet/intel/i40e/i40e.h | 2 +- > drivers/net/ethernet/intel/i40e/i40e_debugfs.c | 10 ++++------ > drivers/net/ethernet/intel/i40e/i40e_main.c | 4 ++-- > drivers/net/ethernet/intel/i40e/i40e_trace.h | 6 +++--- > drivers/net/ethernet/intel/i40e/i40e_txrx.c | 6 +++--- > drivers/net/ethernet/intel/i40e/i40e_txrx.h | 2 +- > drivers/net/ethernet/intel/i40e/i40e_type.h | 5 ++++- > 7 files changed, 18 insertions(+), 17 deletions(-) > Tested-by: Aaron Brown <aaron.f.brown@xxxxxxxxx>
