From: Maciej Fijalkowski <maciej.fijalkowski@xxxxxxxxx>
Date: Fri, 21 Jan 2022 13:00:10 +0100
> Apply the logic that was done for regular XDP from commit 9610bd988df9
> ("ice: optimize XDP_TX workloads") to the ZC side of the driver. On top
> of that, introduce batching to Tx that is inspired by i40e's
> implementation with adjustments to the cleaning logic - take into the
> account NAPI budget in ice_clean_xdp_irq_zc().
>
> Separating the stats structs onto separate cache lines seemed to improve
> the performance.
>
> 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 | 2 +-
> drivers/net/ethernet/intel/ice/ice_xsk.c | 256 ++++++++++++++--------
> drivers/net/ethernet/intel/ice/ice_xsk.h | 27 ++-
> 4 files changed, 186 insertions(+), 101 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/ice/ice_txrx.c b/drivers/net/ethernet/intel/ice/ice_txrx.c
> index bfb9158b10a4..7ab8c700c884 100644
> --- a/drivers/net/ethernet/intel/ice/ice_txrx.c
> +++ b/drivers/net/ethernet/intel/ice/ice_txrx.c
> @@ -1463,7 +1463,7 @@ int ice_napi_poll(struct napi_struct *napi, int budget)
> bool wd;
>
> if (tx_ring->xsk_pool)
> - wd = ice_clean_tx_irq_zc(tx_ring, budget);
> + wd = ice_xmit_zc(tx_ring, ICE_DESC_UNUSED(tx_ring), budget);
> else if (ice_ring_is_xdp(tx_ring))
> wd = true;
> else
> diff --git a/drivers/net/ethernet/intel/ice/ice_txrx.h b/drivers/net/ethernet/intel/ice/ice_txrx.h
> index 09c8ad2f7403..191f9b8c50ee 100644
> --- a/drivers/net/ethernet/intel/ice/ice_txrx.h
> +++ b/drivers/net/ethernet/intel/ice/ice_txrx.h
> @@ -322,9 +322,9 @@ struct ice_tx_ring {
> u16 count; /* Number of descriptors */
> u16 q_index; /* Queue number of ring */
> /* stats structs */
> + struct ice_txq_stats tx_stats;
> struct ice_q_stats stats;
> struct u64_stats_sync syncp;
> - struct ice_txq_stats tx_stats;
>
> /* CL3 - 3rd cacheline starts here */
> struct rcu_head rcu; /* to avoid race on free */
> diff --git a/drivers/net/ethernet/intel/ice/ice_xsk.c b/drivers/net/ethernet/intel/ice/ice_xsk.c
> index 0463fc594d08..4b6e54f75af6 100644
> --- a/drivers/net/ethernet/intel/ice/ice_xsk.c
> +++ b/drivers/net/ethernet/intel/ice/ice_xsk.c
> @@ -671,134 +671,208 @@ int ice_clean_rx_irq_zc(struct ice_rx_ring *rx_ring, int budget)
> }
>
> /**
> - * ice_xmit_zc - Completes AF_XDP entries, and cleans XDP entries
> + * ice_clean_xdp_tx_buf - Free and unmap XDP Tx buffer
> * @xdp_ring: XDP Tx ring
> - * @budget: max number of frames to xmit
> - *
> - * Returns true if cleanup/transmission is done.
> + * @tx_buf: Tx buffer to clean
> */
> -static bool ice_xmit_zc(struct ice_tx_ring *xdp_ring, int budget)
> +static void
> +ice_clean_xdp_tx_buf(struct ice_tx_ring *xdp_ring, struct ice_tx_buf *tx_buf)
> {
> - struct ice_tx_desc *tx_desc = NULL;
> - bool work_done = true;
> - struct xdp_desc desc;
> - dma_addr_t dma;
> -
> - while (likely(budget-- > 0)) {
> - struct ice_tx_buf *tx_buf;
> -
> - if (unlikely(!ICE_DESC_UNUSED(xdp_ring))) {
> - xdp_ring->tx_stats.tx_busy++;
> - work_done = false;
> - break;
> - }
> + xdp_return_frame((struct xdp_frame *)tx_buf->raw_buf);
> + dma_unmap_single(xdp_ring->dev, dma_unmap_addr(tx_buf, dma),
> + dma_unmap_len(tx_buf, len), DMA_TO_DEVICE);
> + dma_unmap_len_set(tx_buf, len, 0);
> +}
>
> - tx_buf = &xdp_ring->tx_buf[xdp_ring->next_to_use];
> +/**
> + * ice_clean_xdp_irq_zc - Reclaim resources after transmit completes on XDP ring
> + * @xdp_ring: XDP ring to clean
> + * @napi_budget: amount of descriptors that NAPI allows us to clean
> + *
> + * Returns count of cleaned descriptors
> + */
> +static u16 ice_clean_xdp_irq_zc(struct ice_tx_ring *xdp_ring, int napi_budget)
> +{
> + u16 tx_thresh = xdp_ring->tx_thresh;
> + int budget = napi_budget / tx_thresh;
> + u16 ntc = xdp_ring->next_to_clean;
> + struct ice_tx_desc *next_dd_desc;
@next_dd_desc is used only inside the `do { } while`, can be moved
there the reduce the scope.
> + u16 next_dd = xdp_ring->next_dd;
> + u16 desc_cnt = xdp_ring->count;
> + struct ice_tx_buf *tx_buf;
> + u16 cleared_dds = 0;
> + u32 xsk_frames = 0;
> + u16 i;
Same with these 5, from @desc_cnt to @i.
>
> - if (!xsk_tx_peek_desc(xdp_ring->xsk_pool, &desc))
> + do {
> + next_dd_desc = ICE_TX_DESC(xdp_ring, next_dd);
> + if (!(next_dd_desc->cmd_type_offset_bsz &
> + cpu_to_le64(ICE_TX_DESC_DTYPE_DESC_DONE)))
> break;
>
> - dma = xsk_buff_raw_get_dma(xdp_ring->xsk_pool, desc.addr);
> - xsk_buff_raw_dma_sync_for_device(xdp_ring->xsk_pool, dma,
> - desc.len);
> + cleared_dds++;
> + xsk_frames = 0;
>
> - tx_buf->bytecount = desc.len;
> + for (i = 0; i < tx_thresh; i++) {
> + tx_buf = &xdp_ring->tx_buf[ntc];
>
> - tx_desc = ICE_TX_DESC(xdp_ring, xdp_ring->next_to_use);
> - tx_desc->buf_addr = cpu_to_le64(dma);
> - tx_desc->cmd_type_offset_bsz =
> - ice_build_ctob(ICE_TXD_LAST_DESC_CMD, 0, desc.len, 0);
> + if (tx_buf->raw_buf) {
> + ice_clean_xdp_tx_buf(xdp_ring, tx_buf);
> + tx_buf->raw_buf = NULL;
> + } else {
> + xsk_frames++;
> + }
>
> - xdp_ring->next_to_use++;
> - if (xdp_ring->next_to_use == xdp_ring->count)
> - xdp_ring->next_to_use = 0;
> - }
> + ntc++;
> + if (ntc >= xdp_ring->count)
> + ntc = 0;
> + }
> + if (xsk_frames)
> + xsk_tx_completed(xdp_ring->xsk_pool, xsk_frames);
> + next_dd_desc->cmd_type_offset_bsz = 0;
> + next_dd = next_dd + tx_thresh;
> + if (next_dd >= desc_cnt)
> + next_dd = tx_thresh - 1;
> + } while (budget--);
>
> - if (tx_desc) {
> - ice_xdp_ring_update_tail(xdp_ring);
> - xsk_tx_release(xdp_ring->xsk_pool);
> - }
> + xdp_ring->next_to_clean = ntc;
> + xdp_ring->next_dd = next_dd;
>
> - return budget > 0 && work_done;
> + return cleared_dds * tx_thresh;
> }
>
> /**
> - * ice_clean_xdp_tx_buf - Free and unmap XDP Tx buffer
> - * @xdp_ring: XDP Tx ring
> - * @tx_buf: Tx buffer to clean
> + * ice_xmit_pkt - produce a single HW Tx descriptor out of AF_XDP descriptor
> + * @xdp_ring: XDP ring to produce the HW Tx descriptor on
> + * @desc: AF_XDP descriptor to pull the DMA address and length from
> + * @total_bytes: bytes accumulator that will be used for stats update
> */
> -static void
> -ice_clean_xdp_tx_buf(struct ice_tx_ring *xdp_ring, struct ice_tx_buf *tx_buf)
> +static void ice_xmit_pkt(struct ice_tx_ring *xdp_ring, struct xdp_desc *desc,
> + unsigned int *total_bytes)
> {
> - xdp_return_frame((struct xdp_frame *)tx_buf->raw_buf);
> - dma_unmap_single(xdp_ring->dev, dma_unmap_addr(tx_buf, dma),
> - dma_unmap_len(tx_buf, len), DMA_TO_DEVICE);
> - dma_unmap_len_set(tx_buf, len, 0);
> + struct ice_tx_desc *tx_desc;
> + dma_addr_t dma;
> +
> + dma = xsk_buff_raw_get_dma(xdp_ring->xsk_pool, desc->addr);
> + xsk_buff_raw_dma_sync_for_device(xdp_ring->xsk_pool, dma, desc->len);
> +
> + tx_desc = ICE_TX_DESC(xdp_ring, xdp_ring->next_to_use++);
> + tx_desc->buf_addr = cpu_to_le64(dma);
> + tx_desc->cmd_type_offset_bsz = ice_build_ctob(ICE_TX_DESC_CMD_EOP,
> + 0, desc->len, 0);
> +
> + *total_bytes += desc->len;
> }
>
> /**
> - * ice_clean_tx_irq_zc - Completes AF_XDP entries, and cleans XDP entries
> - * @xdp_ring: XDP Tx ring
> - * @budget: NAPI budget
> - *
> - * Returns true if cleanup/tranmission is done.
> + * ice_xmit_pkt_batch - produce a batch of HW Tx descriptors out of AF_XDP descriptors
> + * @xdp_ring: XDP ring to produce the HW Tx descriptors on
> + * @descs: AF_XDP descriptors to pull the DMA addresses and lengths from
> + * @total_bytes: bytes accumulator that will be used for stats update
> */
> -bool ice_clean_tx_irq_zc(struct ice_tx_ring *xdp_ring, int budget)
> +static void ice_xmit_pkt_batch(struct ice_tx_ring *xdp_ring, struct xdp_desc *descs,
> + unsigned int *total_bytes)
> {
> - int total_packets = 0, total_bytes = 0;
> - s16 ntc = xdp_ring->next_to_clean;
> + u16 tx_thresh = xdp_ring->tx_thresh;
> + u16 ntu = xdp_ring->next_to_use;
> struct ice_tx_desc *tx_desc;
> - struct ice_tx_buf *tx_buf;
> - u32 xsk_frames = 0;
> - bool xmit_done;
> + dma_addr_t dma;
Same with @dma here.
> + u32 i;
>
> - tx_desc = ICE_TX_DESC(xdp_ring, ntc);
> - tx_buf = &xdp_ring->tx_buf[ntc];
> - ntc -= xdp_ring->count;
> + loop_unrolled_for(i = 0; i < PKTS_PER_BATCH; i++) {
> + dma = xsk_buff_raw_get_dma(xdp_ring->xsk_pool, descs[i].addr);
> + xsk_buff_raw_dma_sync_for_device(xdp_ring->xsk_pool, dma, descs[i].len);
>
> - do {
> - if (!(tx_desc->cmd_type_offset_bsz &
> - cpu_to_le64(ICE_TX_DESC_DTYPE_DESC_DONE)))
> - break;
> + tx_desc = ICE_TX_DESC(xdp_ring, ntu++);
> + tx_desc->buf_addr = cpu_to_le64(dma);
> + tx_desc->cmd_type_offset_bsz = ice_build_ctob(ICE_TX_DESC_CMD_EOP,
> + 0, descs[i].len, 0);
>
> - total_bytes += tx_buf->bytecount;
> - total_packets++;
> + *total_bytes += descs[i].len;
> + }
>
> - if (tx_buf->raw_buf) {
> - ice_clean_xdp_tx_buf(xdp_ring, tx_buf);
> - tx_buf->raw_buf = NULL;
> - } else {
> - xsk_frames++;
> - }
> + xdp_ring->next_to_use = ntu;
>
> - tx_desc->cmd_type_offset_bsz = 0;
> - tx_buf++;
> - tx_desc++;
> - ntc++;
> + if (xdp_ring->next_to_use > xdp_ring->next_rs) {
> + tx_desc = ICE_TX_DESC(xdp_ring, xdp_ring->next_rs);
> + tx_desc->cmd_type_offset_bsz |=
> + cpu_to_le64(ICE_TX_DESC_CMD_RS << ICE_TXD_QW1_CMD_S);
> + xdp_ring->next_rs += tx_thresh;
> + }
> +}
>
> - if (unlikely(!ntc)) {
> - ntc -= xdp_ring->count;
> - tx_buf = xdp_ring->tx_buf;
> - tx_desc = ICE_TX_DESC(xdp_ring, 0);
> - }
> +/**
> + * ice_fill_tx_hw_ring - produce the number of Tx descriptors onto ring
> + * @xdp_ring: XDP ring to produce the HW Tx descriptors on
> + * @descs: AF_XDP descriptors to pull the DMA addresses and lengths from
> + * @nb_pkts: count of packets to be send
> + * @total_bytes: bytes accumulator that will be used for stats update
> + */
> +static void ice_fill_tx_hw_ring(struct ice_tx_ring *xdp_ring, struct xdp_desc *descs,
> + u32 nb_pkts, unsigned int *total_bytes)
> +{
> + u16 tx_thresh = xdp_ring->tx_thresh;
> + struct ice_tx_desc *tx_desc;
And @tx_desc as well.
> + u32 batched, leftover, i;
> +
> + batched = nb_pkts & ~(PKTS_PER_BATCH - 1);
> + leftover = nb_pkts & (PKTS_PER_BATCH - 1);
> + for (i = 0; i < batched; i += PKTS_PER_BATCH)
> + ice_xmit_pkt_batch(xdp_ring, &descs[i], total_bytes);
> + for (i = batched; i < batched + leftover; i++)
> + ice_xmit_pkt(xdp_ring, &descs[i], total_bytes);
> +
> + if (xdp_ring->next_to_use > xdp_ring->next_rs) {
> + tx_desc = ICE_TX_DESC(xdp_ring, xdp_ring->next_rs);
> + tx_desc->cmd_type_offset_bsz |=
> + cpu_to_le64(ICE_TX_DESC_CMD_RS << ICE_TXD_QW1_CMD_S);
> + xdp_ring->next_rs += tx_thresh;
> + }
> +}
>
> - prefetch(tx_desc);
> +/**
> + * ice_xmit_zc - take entries from XSK Tx ring and place them onto HW Tx ring
> + * @xdp_ring: XDP ring to produce the HW Tx descriptors on
> + * @budget: number of free descriptors on HW Tx ring that can be used
> + * @napi_budget: amount of descriptors that NAPI allows us to clean
> + *
> + * Returns true if there is no more work that needs to be done, false otherwise
> + */
> +bool ice_xmit_zc(struct ice_tx_ring *xdp_ring, u32 budget, int napi_budget)
> +{
> + struct xdp_desc *descs = xdp_ring->xsk_pool->tx_descs;
> + u16 tx_thresh = xdp_ring->tx_thresh;
> + u32 nb_pkts, nb_processed = 0;
> + unsigned int total_bytes = 0;
> + struct ice_tx_desc *tx_desc;
And this @tx_desc.
>
> - } while (likely(--budget));
> + if (budget < tx_thresh)
> + budget += ice_clean_xdp_irq_zc(xdp_ring, napi_budget);
> +
> + nb_pkts = xsk_tx_peek_release_desc_batch(xdp_ring->xsk_pool, budget);
> + if (!nb_pkts)
> + return true;
> +
> + if (xdp_ring->next_to_use + nb_pkts >= xdp_ring->count) {
> + nb_processed = xdp_ring->count - xdp_ring->next_to_use;
> + ice_fill_tx_hw_ring(xdp_ring, descs, nb_processed, &total_bytes);
> + tx_desc = ICE_TX_DESC(xdp_ring, xdp_ring->next_rs);
> + tx_desc->cmd_type_offset_bsz |=
> + cpu_to_le64(ICE_TX_DESC_CMD_RS << ICE_TXD_QW1_CMD_S);
> + xdp_ring->next_rs = tx_thresh - 1;
> + xdp_ring->next_to_use = 0;
> + }
>
> - ntc += xdp_ring->count;
> - xdp_ring->next_to_clean = ntc;
> + ice_fill_tx_hw_ring(xdp_ring, &descs[nb_processed], nb_pkts - nb_processed,
> + &total_bytes);
>
> - if (xsk_frames)
> - xsk_tx_completed(xdp_ring->xsk_pool, xsk_frames);
> + ice_xdp_ring_update_tail(xdp_ring);
> + ice_update_tx_ring_stats(xdp_ring, nb_pkts, total_bytes);
>
> if (xsk_uses_need_wakeup(xdp_ring->xsk_pool))
> xsk_set_tx_need_wakeup(xdp_ring->xsk_pool);
>
> - ice_update_tx_ring_stats(xdp_ring, total_packets, total_bytes);
> - xmit_done = ice_xmit_zc(xdp_ring, ICE_DFLT_IRQ_WORK);
> -
> - return budget > 0 && xmit_done;
> + return nb_pkts < budget;
> }
>
> /**
> diff --git a/drivers/net/ethernet/intel/ice/ice_xsk.h b/drivers/net/ethernet/intel/ice/ice_xsk.h
> index 4c7bd8e9dfc4..0cbb5793b5b8 100644
> --- a/drivers/net/ethernet/intel/ice/ice_xsk.h
> +++ b/drivers/net/ethernet/intel/ice/ice_xsk.h
> @@ -6,19 +6,37 @@
> #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
> +
> 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, int napi_budget);
> #else
> +static inline bool
> +ice_xmit_zc(struct ice_tx_ring __always_unused *xdp_ring,
> + u32 __always_unused budget,
> + int __always_unused napi_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 +52,6 @@ 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
