From: Maciej Fijalkowski <maciej.fijalkowski@xxxxxxxxx>
Date: Thu, 16 Dec 2021 14:59:57 +0100
> Follow mostly the logic from commit 9610bd988df9 ("ice: optimize XDP_TX
> workloads") that has been done in order to address the massive tx_busy
> statistic bump and improve the performance as well.
>
> Increase the ICE_TX_THRESH to 64 as it seems to work out better for both
> XDP and AF_XDP. Also, separating the stats structs onto separate cache
> lines seemed to improve the performance. Batching approach is inspired
> by i40e's implementation with adjustments to the cleaning logic.
>
> One difference from 'xdpdrv' XDP_TX is when ring has less than
> ICE_TX_THRESH free entries, the cleaning routine will not stop after
> cleaning a single ICE_TX_THRESH amount of descs but rather will forward
> the next_dd pointer and check the DD bit and for this bit being set the
> cleaning will be repeated. IOW clean until there are descs that can be
> cleaned.
>
> It takes three separate xdpsock instances in txonly mode to achieve the
> line rate and this was not previously possible.
>
> Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@xxxxxxxxx>
> ---
> drivers/net/ethernet/intel/ice/ice_txrx.c | 2 +-
> drivers/net/ethernet/intel/ice/ice_txrx.h | 4 +-
> drivers/net/ethernet/intel/ice/ice_xsk.c | 249 ++++++++++++++--------
> drivers/net/ethernet/intel/ice/ice_xsk.h | 26 ++-
> 4 files changed, 182 insertions(+), 99 deletions(-)
>
-- 8< --
> diff --git a/drivers/net/ethernet/intel/ice/ice_xsk.h b/drivers/net/ethernet/intel/ice/ice_xsk.h
> index 4c7bd8e9dfc4..f2eb99063c1f 100644
> --- a/drivers/net/ethernet/intel/ice/ice_xsk.h
> +++ b/drivers/net/ethernet/intel/ice/ice_xsk.h
> @@ -6,19 +6,36 @@
> #include "ice_txrx.h"
> #include "ice.h"
>
> +#define PKTS_PER_BATCH 8
> +
> +#ifdef __clang__
> +#define loop_unrolled_for _Pragma("clang loop unroll_count(8)") for
> +#elif __GNUC__ >= 4
> +#define loop_unrolled_for _Pragma("GCC unroll 8") for
> +#else
> +#define loop_unrolled_for for
> +#endif
It's used in a bunch more places across the tree, what about
defining that in linux/compiler{,_clang,_gcc}.h?
Is it possible to pass '8' as an argument? Like
loop_unrolled_for(PKTS_PER_BATCH) ( ; ; ) { }
Could be quite handy.
If it is not, I'd maybe try to define a couple of precoded macros
for 8, 16 and 32, like
#define loop_unrolled_for_8 ...
#define loop_unrolled_for_16 ...
...
So they could be used as generic. I don't think I've seen them with
values other than 8-32.
> +
> struct ice_vsi;
>
> #ifdef CONFIG_XDP_SOCKETS
> int ice_xsk_pool_setup(struct ice_vsi *vsi, struct xsk_buff_pool *pool,
> u16 qid);
> int ice_clean_rx_irq_zc(struct ice_rx_ring *rx_ring, int budget);
> -bool ice_clean_tx_irq_zc(struct ice_tx_ring *xdp_ring, int budget);
> int ice_xsk_wakeup(struct net_device *netdev, u32 queue_id, u32 flags);
> bool ice_alloc_rx_bufs_zc(struct ice_rx_ring *rx_ring, u16 count);
> bool ice_xsk_any_rx_ring_ena(struct ice_vsi *vsi);
> void ice_xsk_clean_rx_ring(struct ice_rx_ring *rx_ring);
> void ice_xsk_clean_xdp_ring(struct ice_tx_ring *xdp_ring);
> +bool ice_xmit_zc(struct ice_tx_ring *xdp_ring, u32 budget);
> #else
> +static inline bool
> +ice_xmit_zc(struct ice_tx_ring __always_unused *xdp_ring,
> + u32 __always_unused budget)
> +{
> + return false;
> +}
> +
> static inline int
> ice_xsk_pool_setup(struct ice_vsi __always_unused *vsi,
> struct xsk_buff_pool __always_unused *pool,
> @@ -34,13 +51,6 @@ ice_clean_rx_irq_zc(struct ice_rx_ring __always_unused *rx_ring,
> return 0;
> }
>
> -static inline bool
> -ice_clean_tx_irq_zc(struct ice_tx_ring __always_unused *xdp_ring,
> - int __always_unused budget)
> -{
> - return false;
> -}
> -
> static inline bool
> ice_alloc_rx_bufs_zc(struct ice_rx_ring __always_unused *rx_ring,
> u16 __always_unused count)
> --
> 2.33.1
Thanks,
Al
