| Message ID | 1742391746-118647-1-git-send-email-tariqt@nvidia.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [net-next] net/mlx5e: TX, Utilize WQ fragments edge for multi-packet WQEs | expand |
On Wed, Mar 19, 2025 at 03:42:26PM +0200, Tariq Toukan wrote: > For simplicity reasons, the driver avoids crossing work queue fragment > boundaries within the same TX WQE (Work-Queue Element). Until today, as > the number of packets in a TX MPWQE (Multi-Packet WQE) descriptor is not > known in advance, the driver pre-prepared contiguous memory for the > largest possible WQE. For this, when getting too close to the fragment > edge, having no room for the largest WQE possible, the driver was > filling the fragment remainder with NOP descriptors, aligning the next > descriptor to the beginning of the next fragment. > > Generating and handling these NOPs wastes resources, like: CPU cycles, > work-queue entries fetched to the device, and PCI bandwidth. > > In this patch, we replace this NOPs filling mechanism in the TX MPWQE > flow. Instead, we utilize the remaining entries of the fragment with a > TX MPWQE. If this room turns out to be too small, we simply open an > additional descriptor starting at the beginning of the next fragment. > > Performance benchmark: > uperf test, single server against 3 clients. > TCP multi-stream, bidir, traffic profile "2x350B read, 1400B write". > Bottleneck is in inbound PCI bandwidth (device POV). > > +---------------+------------+------------+--------+ > | | Before | After | | > +---------------+------------+------------+--------+ > | BW | 117.4 Gbps | 121.1 Gbps | +3.1% | > +---------------+------------+------------+--------+ > | tx_packets | 15 M/sec | 15.5 M/sec | +3.3% | > +---------------+------------+------------+--------+ > | tx_nops | 3 M/sec | 0 | -100% | > +---------------+------------+------------+--------+ > > Signed-off-by: Tariq Toukan <tariqt@nvidia.com> > Reviewed-by: Dragos Tatulea <dtatulea@nvidia.com> Reviewed-by: Simon Horman <horms@kernel.org>
Hello: This patch was applied to netdev/net-next.git (main) by Jakub Kicinski <kuba@kernel.org>: On Wed, 19 Mar 2025 15:42:26 +0200 you wrote: > For simplicity reasons, the driver avoids crossing work queue fragment > boundaries within the same TX WQE (Work-Queue Element). Until today, as > the number of packets in a TX MPWQE (Multi-Packet WQE) descriptor is not > known in advance, the driver pre-prepared contiguous memory for the > largest possible WQE. For this, when getting too close to the fragment > edge, having no room for the largest WQE possible, the driver was > filling the fragment remainder with NOP descriptors, aligning the next > descriptor to the beginning of the next fragment. > > [...] Here is the summary with links: - [net-next] net/mlx5e: TX, Utilize WQ fragments edge for multi-packet WQEs https://git.kernel.org/netdev/net-next/c/9da10c2d69c3 You are awesome, thank you!
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h b/drivers/net/ethernet/mellanox/mlx5/core/en.h index 8df185e2ef7f..32ed4963b8ad 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en.h +++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h @@ -398,6 +398,7 @@ struct mlx5e_tx_mpwqe { struct mlx5e_tx_wqe *wqe; u32 bytes_count; u8 ds_count; + u8 ds_count_max; u8 pkt_count; u8 inline_on; }; diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/txrx.h b/drivers/net/ethernet/mellanox/mlx5/core/en/txrx.h index 5ec468268d1a..e837c21d3d21 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en/txrx.h +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/txrx.h @@ -214,6 +214,19 @@ static inline u16 mlx5e_txqsq_get_next_pi(struct mlx5e_txqsq *sq, u16 size) return pi; } +static inline u16 mlx5e_txqsq_get_next_pi_anysize(struct mlx5e_txqsq *sq, + u16 *size) +{ + struct mlx5_wq_cyc *wq = &sq->wq; + u16 pi, contig_wqebbs; + + pi = mlx5_wq_cyc_ctr2ix(wq, sq->pc); + contig_wqebbs = mlx5_wq_cyc_get_contig_wqebbs(wq, pi); + *size = min_t(u16, contig_wqebbs, sq->max_sq_mpw_wqebbs); + + return pi; +} + void mlx5e_txqsq_wake(struct mlx5e_txqsq *sq); static inline u16 mlx5e_shampo_get_cqe_header_index(struct mlx5e_rq *rq, struct mlx5_cqe64 *cqe) @@ -358,9 +371,9 @@ mlx5e_tx_dma_unmap(struct device *pdev, struct mlx5e_sq_dma *dma) void mlx5e_tx_mpwqe_ensure_complete(struct mlx5e_txqsq *sq); -static inline bool mlx5e_tx_mpwqe_is_full(struct mlx5e_tx_mpwqe *session, u8 max_sq_mpw_wqebbs) +static inline bool mlx5e_tx_mpwqe_is_full(struct mlx5e_tx_mpwqe *session) { - return session->ds_count == max_sq_mpw_wqebbs * MLX5_SEND_WQEBB_NUM_DS; + return session->ds_count == session->ds_count_max; } static inline void mlx5e_rqwq_reset(struct mlx5e_rq *rq) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c index 6f3094a479e1..f803e1c93590 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.c @@ -390,6 +390,7 @@ static void mlx5e_xdp_mpwqe_session_start(struct mlx5e_xdpsq *sq) .wqe = wqe, .bytes_count = 0, .ds_count = MLX5E_TX_WQE_EMPTY_DS_COUNT, + .ds_count_max = sq->max_sq_mpw_wqebbs * MLX5_SEND_WQEBB_NUM_DS, .pkt_count = 0, .inline_on = mlx5e_xdp_get_inline_state(sq, session->inline_on), }; @@ -501,7 +502,7 @@ mlx5e_xmit_xdp_frame_mpwqe(struct mlx5e_xdpsq *sq, struct mlx5e_xmit_data *xdptx mlx5e_xdp_mpwqe_add_dseg(sq, p, stats); - if (unlikely(mlx5e_xdp_mpwqe_is_full(session, sq->max_sq_mpw_wqebbs))) + if (unlikely(mlx5e_xdp_mpwqe_is_full(session))) mlx5e_xdp_mpwqe_complete(sq); stats->xmit++; diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.h b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.h index e054db1e10f8..446e492c6bb8 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.h +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.h @@ -182,13 +182,13 @@ static inline bool mlx5e_xdp_get_inline_state(struct mlx5e_xdpsq *sq, bool cur) return cur; } -static inline bool mlx5e_xdp_mpwqe_is_full(struct mlx5e_tx_mpwqe *session, u8 max_sq_mpw_wqebbs) +static inline bool mlx5e_xdp_mpwqe_is_full(struct mlx5e_tx_mpwqe *session) { if (session->inline_on) return session->ds_count + MLX5E_XDP_INLINE_WQE_MAX_DS_CNT > - max_sq_mpw_wqebbs * MLX5_SEND_WQEBB_NUM_DS; + session->ds_count_max; - return mlx5e_tx_mpwqe_is_full(session, max_sq_mpw_wqebbs); + return mlx5e_tx_mpwqe_is_full(session); } struct mlx5e_xdp_wqe_info { diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c index f8c7912abe0e..4fd853d19e31 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c @@ -525,9 +525,9 @@ static void mlx5e_tx_mpwqe_session_start(struct mlx5e_txqsq *sq, { struct mlx5e_tx_mpwqe *session = &sq->mpwqe; struct mlx5e_tx_wqe *wqe; - u16 pi; + u16 pi, num_wqebbs; - pi = mlx5e_txqsq_get_next_pi(sq, sq->max_sq_mpw_wqebbs); + pi = mlx5e_txqsq_get_next_pi_anysize(sq, &num_wqebbs); wqe = MLX5E_TX_FETCH_WQE(sq, pi); net_prefetchw(wqe->data); @@ -535,6 +535,7 @@ static void mlx5e_tx_mpwqe_session_start(struct mlx5e_txqsq *sq, .wqe = wqe, .bytes_count = 0, .ds_count = MLX5E_TX_WQE_EMPTY_DS_COUNT, + .ds_count_max = num_wqebbs * MLX5_SEND_WQEBB_NUM_DS, .pkt_count = 0, .inline_on = 0, }; @@ -626,7 +627,7 @@ mlx5e_sq_xmit_mpwqe(struct mlx5e_txqsq *sq, struct sk_buff *skb, mlx5e_tx_mpwqe_add_dseg(sq, &txd); mlx5e_tx_skb_update_hwts_flags(skb); - if (unlikely(mlx5e_tx_mpwqe_is_full(&sq->mpwqe, sq->max_sq_mpw_wqebbs))) { + if (unlikely(mlx5e_tx_mpwqe_is_full(&sq->mpwqe))) { /* Might stop the queue and affect the retval of __netdev_tx_sent_queue. */ cseg = mlx5e_tx_mpwqe_session_complete(sq);