On 11/17/20 11:06 AM, Joyce Kong wrote:
> Optimize packed ring Rx batch path with NEON instructions.
>
> Signed-off-by: Joyce Kong <joyce.k...@arm.com>
> Reviewed-by: Ruifeng Wang <ruifeng.w...@arm.com>
> ---
> drivers/net/virtio/virtio_rxtx_packed.h | 15 ++
> drivers/net/virtio/virtio_rxtx_packed_neon.h | 150 +++++++++++++++++++
> 2 files changed, 165 insertions(+)
> create mode 100644 drivers/net/virtio/virtio_rxtx_packed_neon.h
>
> diff --git a/drivers/net/virtio/virtio_rxtx_packed.h
> b/drivers/net/virtio/virtio_rxtx_packed.h
> index b0b1d63ec..8f5198ad7 100644
> --- a/drivers/net/virtio/virtio_rxtx_packed.h
> +++ b/drivers/net/virtio/virtio_rxtx_packed.h
> @@ -19,9 +19,16 @@
> #include "virtqueue.h"
>
> #define BYTE_SIZE 8
> +
> +#ifdef CC_AVX512_SUPPORT
> /* flag bits offset in packed ring desc higher 64bits */
> #define FLAGS_BITS_OFFSET ((offsetof(struct vring_packed_desc, flags) - \
> offsetof(struct vring_packed_desc, len)) * BYTE_SIZE)
> +#elif defined(RTE_ARCH_ARM)
> +/* flag bits offset in packed ring desc from ID */
> +#define FLAGS_BITS_OFFSET ((offsetof(struct vring_packed_desc, flags) - \
> + offsetof(struct vring_packed_desc, id)) * BYTE_SIZE)
> +#endif
>
> #define PACKED_FLAGS_MASK ((0ULL | VRING_PACKED_DESC_F_AVAIL_USED) << \
> FLAGS_BITS_OFFSET)
> @@ -44,8 +51,16 @@
> /* net hdr short size mask */
> #define NET_HDR_MASK 0x3F
>
> +#ifdef RTE_ARCH_ARM
> +/* The cache line size on different Arm platforms are different, so
> + * put a four batch size here to match with the minimum cache line
> + * size and accommodate NEON register size.
> + */
> +#define PACKED_BATCH_SIZE 4
> +#else
> #define PACKED_BATCH_SIZE (RTE_CACHE_LINE_SIZE / \
> sizeof(struct vring_packed_desc))
> +#endif
> #define PACKED_BATCH_MASK (PACKED_BATCH_SIZE - 1)
>
> #ifdef VIRTIO_GCC_UNROLL_PRAGMA
> diff --git a/drivers/net/virtio/virtio_rxtx_packed_neon.h
> b/drivers/net/virtio/virtio_rxtx_packed_neon.h
> new file mode 100644
> index 000000000..fb1e49909
> --- /dev/null
> +++ b/drivers/net/virtio/virtio_rxtx_packed_neon.h
> @@ -0,0 +1,150 @@
> +/* SPDX-License-Identifier: BSD-3-Clause
> + * Copyright(c) 2020 Arm Corporation
> + */
> +
> +#include <stdlib.h>
> +#include <stdint.h>
> +#include <stdio.h>
> +#include <string.h>
> +#include <errno.h>
> +
> +#include <rte_net.h>
> +#include <rte_vect.h>
> +
> +#include "virtio_ethdev.h"
> +#include "virtio_pci.h"
> +#include "virtio_rxtx_packed.h"
> +#include "virtqueue.h"
> +
> +static inline uint16_t
> +virtqueue_dequeue_batch_packed_vec(struct virtnet_rx *rxvq,
> + struct rte_mbuf **rx_pkts)
> +{
> + struct virtqueue *vq = rxvq->vq;
> + struct virtio_hw *hw = vq->hw;
> + uint16_t head_size = hw->vtnet_hdr_size;
> + uint16_t id = vq->vq_used_cons_idx;
> + struct vring_packed_desc *p_desc;
> + uint16_t i;
> +
> + if (id & PACKED_BATCH_MASK)
> + return -1;
> +
> + if (unlikely((id + PACKED_BATCH_SIZE) > vq->vq_nentries))
> + return -1;
This function returns an unsigned short, I think you should return 0
here since it failed to dequeue packets.
> + /* Map packed descriptor to mbuf fields. */
> + uint8x16_t shuf_msk1 = {
> + 0xFF, 0xFF, 0xFF, 0xFF, /* pkt_type set as unknown */
> + 0, 1, /* octet 1~0, low 16 bits pkt_len */
> + 0xFF, 0xFF, /* skip high 16 bits of pkt_len, zero
> out */
> + 0, 1, /* octet 1~0, 16 bits data_len */
> + 0xFF, 0xFF, /* vlan tci set as unknown */
> + 0xFF, 0xFF, 0xFF, 0xFF
> + };
> +
> + uint8x16_t shuf_msk2 = {
> + 0xFF, 0xFF, 0xFF, 0xFF, /* pkt_type set as unknown */
> + 8, 9, /* octet 9~8, low 16 bits pkt_len */
> + 0xFF, 0xFF, /* skip high 16 bits of pkt_len, zero
> out */
> + 8, 9, /* octet 9~8, 16 bits data_len */
> + 0xFF, 0xFF, /* vlan tci set as unknown */
> + 0xFF, 0xFF, 0xFF, 0xFF
> + };
> +
> + /* Subtract the header length. */
> + uint16x8_t len_adjust = {
> + 0, 0, /* ignore pkt_type field */
> + head_size, /* sub head_size on pkt_len */
> + 0, /* ignore high 16 bits of pkt_len */
> + head_size, /* sub head_size on data_len */
> + 0, 0, 0 /* ignore non-length fields */
> + };
> +
> + uint64x2_t desc[PACKED_BATCH_SIZE / 2];
> + uint64x2x2_t mbp[PACKED_BATCH_SIZE / 2];
> + uint64x2_t pkt_mb[PACKED_BATCH_SIZE];
> +
> + p_desc = &vq->vq_packed.ring.desc[id];
> + /* Load high 64 bits of packed descriptor 0,1. */
> + desc[0] = vld2q_u64((uint64_t *)(p_desc)).val[1];
> + /* Load high 64 bits of packed descriptor 2,3. */
> + desc[1] = vld2q_u64((uint64_t *)(p_desc + 2)).val[1];
> +
> + /* Only care avail/used bits. */
> + uint32x4_t v_mask = vdupq_n_u32(PACKED_FLAGS_MASK);
> + /* Extract high 32 bits of packed descriptor (id, flags). */
> + uint32x4_t v_desc = vuzp2q_u32(vreinterpretq_u32_u64(desc[0]),
> + vreinterpretq_u32_u64(desc[1]));
> + uint32x4_t v_flag = vandq_u32(v_desc, v_mask);
> +
> + uint32x4_t v_used_flag = vdupq_n_u32(0);
> + if (vq->vq_packed.used_wrap_counter)
> + v_used_flag = vdupq_n_u32(PACKED_FLAGS_MASK);
> +
> + poly128_t desc_stats = vreinterpretq_p128_u32(~vceqq_u32(v_flag,
> v_used_flag));
> +
> + /* Check all descs are used. */
> + if (desc_stats)
> + return -1;
Same here. You should return 0 here as the queue is full.
> +
> + /* Load 2 mbuf pointers per time. */
> + mbp[0] = vld2q_u64((uint64_t *)&vq->vq_descx[id]);
> + vst1q_u64((uint64_t *)&rx_pkts[0], mbp[0].val[0]);
> +
> + mbp[1] = vld2q_u64((uint64_t *)&vq->vq_descx[id + 2]);
> + vst1q_u64((uint64_t *)&rx_pkts[2], mbp[1].val[0]);
> +
> + /**
> + * Update data length and packet length for descriptor.
> + * structure of pkt_mb:
> + * --------------------------------------------------------------------
> + * |32 bits pkt_type|32 bits pkt_len|16 bits data_len|16 bits vlan_tci|
> + * --------------------------------------------------------------------
> + */
> + pkt_mb[0] = vreinterpretq_u64_u8(vqtbl1q_u8(
> + vreinterpretq_u8_u64(desc[0]), shuf_msk1));
> + pkt_mb[1] = vreinterpretq_u64_u8(vqtbl1q_u8(
> + vreinterpretq_u8_u64(desc[0]), shuf_msk2));
> + pkt_mb[2] = vreinterpretq_u64_u8(vqtbl1q_u8(
> + vreinterpretq_u8_u64(desc[1]), shuf_msk1))'
> + pkt_mb[3] = vreinterpretq_u64_u8(vqtbl1q_u8(
> + vreinterpretq_u8_u64(desc[1]), shuf_msk2));
> +
> + pkt_mb[0] = vreinterpretq_u64_u16(vsubq_u16(
> + vreinterpretq_u16_u64(pkt_mb[0]), len_adjust));
> + pkt_mb[1] = vreinterpretq_u64_u16(vsubq_u16(
> + vreinterpretq_u16_u64(pkt_mb[1]), len_adjust));
> + pkt_mb[2] = vreinterpretq_u64_u16(vsubq_u16(
> + vreinterpretq_u16_u64(pkt_mb[2]), len_adjust));
> + pkt_mb[3] = vreinterpretq_u64_u16(vsubq_u16(
> + vreinterpretq_u16_u64(pkt_mb[3]), len_adjust));
> +
> + vst1q_u64((void *)&rx_pkts[0]->rx_descriptor_fields1, pkt_mb[0]);
> + vst1q_u64((void *)&rx_pkts[1]->rx_descriptor_fields1, pkt_mb[1]);
> + vst1q_u64((void *)&rx_pkts[2]->rx_descriptor_fields1, pkt_mb[2]);
> + vst1q_u64((void *)&rx_pkts[3]->rx_descriptor_fields1, pkt_mb[3]);
> +
> + if (hw->has_rx_offload) {
> + virtio_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
> + char *addr = (char *)rx_pkts[i]->buf_addr +
> + RTE_PKTMBUF_HEADROOM - head_size;
> + virtio_vec_rx_offload(rx_pkts[i],
> + (struct virtio_net_hdr *)addr);
> + }
> + }
> +
> + virtio_update_batch_stats(&rxvq->stats, rx_pkts[0]->pkt_len,
> + rx_pkts[1]->pkt_len, rx_pkts[2]->pkt_len,
> + rx_pkts[3]->pkt_len);
> +
> + vq->vq_free_cnt += PACKED_BATCH_SIZE;
> +
> + vq->vq_used_cons_idx += PACKED_BATCH_SIZE;
> + if (vq->vq_used_cons_idx >= vq->vq_nentries) {
> + vq->vq_used_cons_idx -= vq->vq_nentries;
> + vq->vq_packed.used_wrap_counter ^= 1;
> + }
> +
> + return 0;
> +}
>
