On Sun, Jul 20, 2025 at 05:11:22PM +0800, Jason Xing wrote:
> From: Jason Xing <kernelxing@xxxxxxxxxxx>
>
> Like what i40e driver initially did in commit 3106c580fb7cf
> ("i40e: Use batched xsk Tx interfaces to increase performance"), use
> the batched xsk feature to transmit packets.
>
> Signed-off-by: Jason Xing <kernelxing@xxxxxxxxxxx>
> ---
> drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c | 106 +++++++++++++------
> 1 file changed, 72 insertions(+), 34 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
> index f3d3f5c1cdc7..9fe2c4bf8bc5 100644
> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_xsk.c
> @@ -2,12 +2,15 @@
> /* Copyright(c) 2018 Intel Corporation. */
>
> #include <linux/bpf_trace.h>
> +#include <linux/unroll.h>
> #include <net/xdp_sock_drv.h>
> #include <net/xdp.h>
>
> #include "ixgbe.h"
> #include "ixgbe_txrx_common.h"
>
> +#define PKTS_PER_BATCH 4
> +
> struct xsk_buff_pool *ixgbe_xsk_pool(struct ixgbe_adapter *adapter,
> struct ixgbe_ring *ring)
> {
> @@ -388,58 +391,93 @@ void ixgbe_xsk_clean_rx_ring(struct ixgbe_ring *rx_ring)
> }
> }
>
> -static bool ixgbe_xmit_zc(struct ixgbe_ring *xdp_ring, unsigned int budget)
> +static void ixgbe_set_rs_bit(struct ixgbe_ring *xdp_ring)
> +{
> + u16 ntu = xdp_ring->next_to_use ? xdp_ring->next_to_use - 1 : xdp_ring->count - 1;
> + union ixgbe_adv_tx_desc *tx_desc;
> +
> + tx_desc = IXGBE_TX_DESC(xdp_ring, ntu);
> + tx_desc->read.cmd_type_len |= cpu_to_le32(IXGBE_TXD_CMD_RS);
> +}
> +
> +static void ixgbe_xmit_pkt(struct ixgbe_ring *xdp_ring, struct xdp_desc *desc,
> + int i)
> +
`i` parameter seems redundant here, why not just pass desc + i as a parameter?
> {
> struct xsk_buff_pool *pool = xdp_ring->xsk_pool;
> union ixgbe_adv_tx_desc *tx_desc = NULL;
> struct ixgbe_tx_buffer *tx_bi;
> - struct xdp_desc desc;
> dma_addr_t dma;
> u32 cmd_type;
>
> - if (!budget)
> - return true;
> + dma = xsk_buff_raw_get_dma(pool, desc[i].addr);
> + xsk_buff_raw_dma_sync_for_device(pool, dma, desc[i].len);
>
> - while (likely(budget)) {
> - if (!netif_carrier_ok(xdp_ring->netdev))
> - break;
> + tx_bi = &xdp_ring->tx_buffer_info[xdp_ring->next_to_use];
> + tx_bi->bytecount = desc[i].len;
> + tx_bi->xdpf = NULL;
> + tx_bi->gso_segs = 1;
>
> - if (!xsk_tx_peek_desc(pool, &desc))
> - break;
> + tx_desc = IXGBE_TX_DESC(xdp_ring, xdp_ring->next_to_use);
> + tx_desc->read.buffer_addr = cpu_to_le64(dma);
>
> - dma = xsk_buff_raw_get_dma(pool, desc.addr);
> - xsk_buff_raw_dma_sync_for_device(pool, dma, desc.len);
> + cmd_type = IXGBE_ADVTXD_DTYP_DATA |
> + IXGBE_ADVTXD_DCMD_DEXT |
> + IXGBE_ADVTXD_DCMD_IFCS;
> + cmd_type |= desc[i].len | IXGBE_TXD_CMD_EOP;
> + tx_desc->read.cmd_type_len = cpu_to_le32(cmd_type);
> + tx_desc->read.olinfo_status =
> + cpu_to_le32(desc[i].len << IXGBE_ADVTXD_PAYLEN_SHIFT);
>
> - tx_bi = &xdp_ring->tx_buffer_info[xdp_ring->next_to_use];
> - tx_bi->bytecount = desc.len;
> - tx_bi->xdpf = NULL;
> - tx_bi->gso_segs = 1;
> + xdp_ring->next_to_use++;
> +}
>
> - tx_desc = IXGBE_TX_DESC(xdp_ring, xdp_ring->next_to_use);
> - tx_desc->read.buffer_addr = cpu_to_le64(dma);
> +static void ixgbe_xmit_pkt_batch(struct ixgbe_ring *xdp_ring, struct xdp_desc *desc)
> +{
> + u32 i;
>
> - /* put descriptor type bits */
> - cmd_type = IXGBE_ADVTXD_DTYP_DATA |
> - IXGBE_ADVTXD_DCMD_DEXT |
> - IXGBE_ADVTXD_DCMD_IFCS;
> - cmd_type |= desc.len | IXGBE_TXD_CMD;
> - tx_desc->read.cmd_type_len = cpu_to_le32(cmd_type);
> - tx_desc->read.olinfo_status =
> - cpu_to_le32(desc.len << IXGBE_ADVTXD_PAYLEN_SHIFT);
> + unrolled_count(PKTS_PER_BATCH)
> + for (i = 0; i < PKTS_PER_BATCH; i++)
> + ixgbe_xmit_pkt(xdp_ring, desc, i);
> +}
>
> - xdp_ring->next_to_use++;
> - if (xdp_ring->next_to_use == xdp_ring->count)
> - xdp_ring->next_to_use = 0;
> +static void ixgbe_fill_tx_hw_ring(struct ixgbe_ring *xdp_ring,
> + struct xdp_desc *descs, u32 nb_pkts)
> +{
> + 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)
> + ixgbe_xmit_pkt_batch(xdp_ring, &descs[i]);
> + for (i = batched; i < batched + leftover; i++)
> + ixgbe_xmit_pkt(xdp_ring, &descs[i], 0);
> +}
>
> - budget--;
> - }
> +static bool ixgbe_xmit_zc(struct ixgbe_ring *xdp_ring, unsigned int budget)
> +{
> + struct xdp_desc *descs = xdp_ring->xsk_pool->tx_descs;
> + u32 nb_pkts, nb_processed = 0;
>
> - if (tx_desc) {
> - ixgbe_xdp_ring_update_tail(xdp_ring);
> - xsk_tx_release(pool);
> + if (!netif_carrier_ok(xdp_ring->netdev))
> + return true;
> +
> + 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;
> + ixgbe_fill_tx_hw_ring(xdp_ring, descs, nb_processed);
> + xdp_ring->next_to_use = 0;
> }
>
> - return !!budget;
> + ixgbe_fill_tx_hw_ring(xdp_ring, &descs[nb_processed], nb_pkts - nb_processed);
> +
> + ixgbe_set_rs_bit(xdp_ring);
> + ixgbe_xdp_ring_update_tail(xdp_ring);
> +
> + return nb_pkts < budget;
> }
>
> static void ixgbe_clean_xdp_tx_buffer(struct ixgbe_ring *tx_ring,
> --
> 2.41.3
>
>
