On 14 Aug 2019, at 0:27, Magnus Karlsson wrote: > From: Maxim Mikityanskiy <maximmi@xxxxxxxxxxxx> > > This commit adds support for the new need_wakeup feature of AF_XDP. The > applications can opt-in by using the XDP_USE_NEED_WAKEUP bind() flag. > When this feature is enabled, some behavior changes: > > RX side: If the Fill Ring is empty, instead of busy-polling, set the > flag to tell the application to kick the driver when it refills the Fill > Ring. > > TX side: If there are pending completions or packets queued for > transmission, set the flag to tell the application that it can skip the > sendto() syscall and save time. > > The performance testing was performed on a machine with the following > configuration: > > - 24 cores of Intel Xeon E5-2620 v3 @ 2.40 GHz > - Mellanox ConnectX-5 Ex with 100 Gbit/s link > > The results with retpoline disabled: > > | without need_wakeup | with need_wakeup | > |----------------------|----------------------| > | one core | two cores | one core | two cores | > -------|----------|-----------|----------|-----------| > txonly | 20.1 | 33.5 | 29.0 | 34.2 | > rxdrop | 0.065 | 14.1 | 12.0 | 14.1 | > l2fwd | 0.032 | 7.3 | 6.6 | 7.2 | > > "One core" means the application and NAPI run on the same core. "Two > cores" means they are pinned to different cores. > > Signed-off-by: Maxim Mikityanskiy <maximmi@xxxxxxxxxxxx> > Reviewed-by: Tariq Toukan <tariqt@xxxxxxxxxxxx> > Reviewed-by: Saeed Mahameed <saeedm@xxxxxxxxxxxx> Acked-by: Jonathan Lemon <jonathan.lemon@xxxxxxxxx>
