On 1/5/21 3:16 PM, Maxime Coquelin wrote:
>
>
> 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.
Just looked again at the code and at AVX implementation.
It should not return 0 here, but any positive value.
Maybe the cleanest way would change the function prototype to int.
0: success
-1: failure
>> +
>> + /* 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;
>> +}
>>
>
