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numam-dpdk/drivers/net/mlx5/mlx5_rxtx_vec.c
Alexander Kozyrev 0f20acbf5e net/mlx5: implement vectorized MPRQ burst 
MPRQ (Multi-Packet Rx Queue) processes one packet at a time using
simple scalar instructions. MPRQ works by posting a single large buffer
(consisted of multiple fixed-size strides) in order to receive multiple
packets at once on this buffer. A Rx packet is then copied to a
user-provided mbuf or PMD attaches the Rx packet to the mbuf by the
pointer to an external buffer.

There is an opportunity to speed up the packet receiving by processing
4 packets simultaneously using SIMD (single instruction, multiple data)
extensions. Allocate mbufs in batches for every MPRQ buffer and process
the packets in groups of 4 until all the strides are exhausted. Then
switch to another MPRQ buffer and repeat the process over again.

The vectorized MPRQ burst routine is engaged automatically in case
the mprq_en=1 devarg is specified and the vectorization is not disabled
explicitly by providing rx_vec_en=0 devarg. There is a limitation:
LRO is not supported and scalar MPRQ is selected if it is on.

Signed-off-by: Alexander Kozyrev <akozyrev@nvidia.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
2020-11-03 23:24:25 +01:00

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/* SPDX-License-Identifier: BSD-3-Clause
* Copyright 2017 6WIND S.A.
* Copyright 2017 Mellanox Technologies, Ltd
*/
#include <stdint.h>
#include <string.h>
#include <stdlib.h>
#include <rte_mbuf.h>
#include <rte_mempool.h>
#include <rte_prefetch.h>
#include <rte_vect.h>
#include <mlx5_glue.h>
#include <mlx5_prm.h>
#include "mlx5_defs.h"
#include "mlx5.h"
#include "mlx5_utils.h"
#include "mlx5_rxtx.h"
#include "mlx5_rxtx_vec.h"
#include "mlx5_autoconf.h"
#if defined RTE_ARCH_X86_64
#include "mlx5_rxtx_vec_sse.h"
#elif defined RTE_ARCH_ARM64
#include "mlx5_rxtx_vec_neon.h"
#elif defined RTE_ARCH_PPC_64
#include "mlx5_rxtx_vec_altivec.h"
#else
#error "This should not be compiled if SIMD instructions are not supported."
#endif
/**
* Skip error packets.
*
* @param rxq
* Pointer to RX queue structure.
* @param[out] pkts
* Array to store received packets.
* @param pkts_n
* Maximum number of packets in array.
*
* @return
* Number of packets successfully received (<= pkts_n).
*/
static uint16_t
rxq_handle_pending_error(struct mlx5_rxq_data *rxq, struct rte_mbuf **pkts,
uint16_t pkts_n)
{
uint16_t n = 0;
unsigned int i;
#ifdef MLX5_PMD_SOFT_COUNTERS
uint32_t err_bytes = 0;
#endif
for (i = 0; i < pkts_n; ++i) {
struct rte_mbuf *pkt = pkts[i];
if (pkt->packet_type == RTE_PTYPE_ALL_MASK || rxq->err_state) {
#ifdef MLX5_PMD_SOFT_COUNTERS
err_bytes += PKT_LEN(pkt);
#endif
rte_pktmbuf_free_seg(pkt);
} else {
pkts[n++] = pkt;
}
}
rxq->stats.idropped += (pkts_n - n);
#ifdef MLX5_PMD_SOFT_COUNTERS
/* Correct counters of errored completions. */
rxq->stats.ipackets -= (pkts_n - n);
rxq->stats.ibytes -= err_bytes;
#endif
mlx5_rx_err_handle(rxq, 1);
return n;
}
/**
* Replenish buffers for RX in bulk.
*
* @param rxq
* Pointer to RX queue structure.
*/
static inline void
mlx5_rx_replenish_bulk_mbuf(struct mlx5_rxq_data *rxq)
{
const uint16_t q_n = 1 << rxq->elts_n;
const uint16_t q_mask = q_n - 1;
uint16_t n = q_n - (rxq->rq_ci - rxq->rq_pi);
uint16_t elts_idx = rxq->rq_ci & q_mask;
struct rte_mbuf **elts = &(*rxq->elts)[elts_idx];
volatile struct mlx5_wqe_data_seg *wq =
&((volatile struct mlx5_wqe_data_seg *)rxq->wqes)[elts_idx];
unsigned int i;
if (n >= rxq->rq_repl_thresh) {
MLX5_ASSERT(n >= MLX5_VPMD_RXQ_RPLNSH_THRESH(q_n));
MLX5_ASSERT(MLX5_VPMD_RXQ_RPLNSH_THRESH(q_n) >
MLX5_VPMD_DESCS_PER_LOOP);
/* Not to cross queue end. */
n = RTE_MIN(n - MLX5_VPMD_DESCS_PER_LOOP, q_n - elts_idx);
if (rte_mempool_get_bulk(rxq->mp, (void *)elts, n) < 0) {
rxq->stats.rx_nombuf += n;
return;
}
for (i = 0; i < n; ++i) {
void *buf_addr;
/*
* In order to support the mbufs with external attached
* data buffer we should use the buf_addr pointer
* instead of rte_mbuf_buf_addr(). It touches the mbuf
* itself and may impact the performance.
*/
buf_addr = elts[i]->buf_addr;
wq[i].addr = rte_cpu_to_be_64((uintptr_t)buf_addr +
RTE_PKTMBUF_HEADROOM);
/* If there's a single MR, no need to replace LKey. */
if (unlikely(mlx5_mr_btree_len(&rxq->mr_ctrl.cache_bh)
> 1))
wq[i].lkey = mlx5_rx_mb2mr(rxq, elts[i]);
}
rxq->rq_ci += n;
/* Prevent overflowing into consumed mbufs. */
elts_idx = rxq->rq_ci & q_mask;
for (i = 0; i < MLX5_VPMD_DESCS_PER_LOOP; ++i)
(*rxq->elts)[elts_idx + i] = &rxq->fake_mbuf;
rte_io_wmb();
*rxq->rq_db = rte_cpu_to_be_32(rxq->rq_ci);
}
}
/**
* Replenish buffers for MPRQ RX in bulk.
*
* @param rxq
* Pointer to RX queue structure.
*/
static inline void
mlx5_rx_mprq_replenish_bulk_mbuf(struct mlx5_rxq_data *rxq)
{
const uint16_t wqe_n = 1 << rxq->elts_n;
const uint32_t strd_n = 1 << rxq->strd_num_n;
const uint32_t elts_n = wqe_n * strd_n;
const uint32_t wqe_mask = elts_n - 1;
uint32_t n = elts_n - (rxq->elts_ci - rxq->rq_pi);
uint32_t elts_idx = rxq->elts_ci & wqe_mask;
struct rte_mbuf **elts = &(*rxq->elts)[elts_idx];
/* Not to cross queue end. */
if (n >= rxq->rq_repl_thresh) {
MLX5_ASSERT(n >= MLX5_VPMD_RXQ_RPLNSH_THRESH(elts_n));
MLX5_ASSERT(MLX5_VPMD_RXQ_RPLNSH_THRESH(elts_n) >
MLX5_VPMD_DESCS_PER_LOOP);
n = RTE_MIN(n, elts_n - elts_idx);
if (rte_mempool_get_bulk(rxq->mp, (void *)elts, n) < 0) {
rxq->stats.rx_nombuf += n;
return;
}
rxq->elts_ci += n;
}
}
/**
* Copy or attach MPRQ buffers to RX SW ring.
*
* @param rxq
* Pointer to RX queue structure.
* @param pkts
* Pointer to array of packets to be stored.
* @param pkts_n
* Number of packets to be stored.
*
* @return
* Number of packets successfully copied/attached (<= pkts_n).
*/
static inline uint16_t
rxq_copy_mprq_mbuf_v(struct mlx5_rxq_data *rxq,
struct rte_mbuf **pkts, uint16_t pkts_n)
{
const uint16_t wqe_n = 1 << rxq->elts_n;
const uint16_t wqe_mask = wqe_n - 1;
const uint16_t strd_sz = 1 << rxq->strd_sz_n;
const uint32_t strd_n = 1 << rxq->strd_num_n;
const uint32_t elts_n = wqe_n * strd_n;
const uint32_t elts_mask = elts_n - 1;
uint32_t elts_idx = rxq->rq_pi & elts_mask;
struct rte_mbuf **elts = &(*rxq->elts)[elts_idx];
uint32_t rq_ci = rxq->rq_ci;
struct mlx5_mprq_buf *buf = (*rxq->mprq_bufs)[rq_ci & wqe_mask];
uint16_t copied = 0;
uint16_t i = 0;
for (i = 0; i < pkts_n; ++i) {
uint16_t strd_cnt;
enum mlx5_rqx_code rxq_code;
if (rxq->consumed_strd == strd_n) {
/* Replace WQE if the buffer is still in use. */
mprq_buf_replace(rxq, rq_ci & wqe_mask);
/* Advance to the next WQE. */
rxq->consumed_strd = 0;
rq_ci++;
buf = (*rxq->mprq_bufs)[rq_ci & wqe_mask];
}
if (!elts[i]->pkt_len) {
rxq->consumed_strd = strd_n;
rte_pktmbuf_free_seg(elts[i]);
#ifdef MLX5_PMD_SOFT_COUNTERS
rxq->stats.ipackets -= 1;
#endif
continue;
}
strd_cnt = (elts[i]->pkt_len / strd_sz) +
((elts[i]->pkt_len % strd_sz) ? 1 : 0);
rxq_code = mprq_buf_to_pkt(rxq, elts[i], elts[i]->pkt_len,
buf, rxq->consumed_strd, strd_cnt);
rxq->consumed_strd += strd_cnt;
if (unlikely(rxq_code != MLX5_RXQ_CODE_EXIT)) {
rte_pktmbuf_free_seg(elts[i]);
#ifdef MLX5_PMD_SOFT_COUNTERS
rxq->stats.ipackets -= 1;
rxq->stats.ibytes -= elts[i]->pkt_len;
#endif
if (rxq_code == MLX5_RXQ_CODE_NOMBUF) {
++rxq->stats.rx_nombuf;
break;
}
if (rxq_code == MLX5_RXQ_CODE_DROPPED) {
++rxq->stats.idropped;
continue;
}
}
pkts[copied++] = elts[i];
}
rxq->rq_pi += i;
rxq->cq_ci += i;
rte_io_wmb();
*rxq->cq_db = rte_cpu_to_be_32(rxq->cq_ci);
if (rq_ci != rxq->rq_ci) {
rxq->rq_ci = rq_ci;
rte_io_wmb();
*rxq->rq_db = rte_cpu_to_be_32(rxq->rq_ci);
}
return copied;
}
/**
* Receive burst of packets. An errored completion also consumes a mbuf, but the
* packet_type is set to be RTE_PTYPE_ALL_MASK. Marked mbufs should be freed
* before returning to application.
*
* @param rxq
* Pointer to RX queue structure.
* @param[out] pkts
* Array to store received packets.
* @param pkts_n
* Maximum number of packets in array.
* @param[out] err
* Pointer to a flag. Set non-zero value if pkts array has at least one error
* packet to handle.
* @param[out] no_cq
* Pointer to a boolean. Set true if no new CQE seen.
*
* @return
* Number of packets received including errors (<= pkts_n).
*/
static inline uint16_t
rxq_burst_v(struct mlx5_rxq_data *rxq, struct rte_mbuf **pkts,
uint16_t pkts_n, uint64_t *err, bool *no_cq)
{
const uint16_t q_n = 1 << rxq->cqe_n;
const uint16_t q_mask = q_n - 1;
const uint16_t e_n = 1 << rxq->elts_n;
const uint16_t e_mask = e_n - 1;
volatile struct mlx5_cqe *cq;
struct rte_mbuf **elts;
uint64_t comp_idx = MLX5_VPMD_DESCS_PER_LOOP;
uint16_t nocmp_n = 0;
uint16_t rcvd_pkt = 0;
unsigned int cq_idx = rxq->cq_ci & q_mask;
unsigned int elts_idx;
MLX5_ASSERT(rxq->sges_n == 0);
MLX5_ASSERT(rxq->cqe_n == rxq->elts_n);
cq = &(*rxq->cqes)[cq_idx];
rte_prefetch0(cq);
rte_prefetch0(cq + 1);
rte_prefetch0(cq + 2);
rte_prefetch0(cq + 3);
pkts_n = RTE_MIN(pkts_n, MLX5_VPMD_RX_MAX_BURST);
mlx5_rx_replenish_bulk_mbuf(rxq);
/* See if there're unreturned mbufs from compressed CQE. */
rcvd_pkt = rxq->decompressed;
if (rcvd_pkt > 0) {
rcvd_pkt = RTE_MIN(rcvd_pkt, pkts_n);
rxq_copy_mbuf_v(&(*rxq->elts)[rxq->rq_pi & e_mask],
pkts, rcvd_pkt);
rxq->rq_pi += rcvd_pkt;
rxq->decompressed -= rcvd_pkt;
pkts += rcvd_pkt;
}
elts_idx = rxq->rq_pi & e_mask;
elts = &(*rxq->elts)[elts_idx];
/* Not to overflow pkts array. */
pkts_n = RTE_ALIGN_FLOOR(pkts_n - rcvd_pkt, MLX5_VPMD_DESCS_PER_LOOP);
/* Not to cross queue end. */
pkts_n = RTE_MIN(pkts_n, q_n - elts_idx);
pkts_n = RTE_MIN(pkts_n, q_n - cq_idx);
if (!pkts_n) {
*no_cq = !rcvd_pkt;
return rcvd_pkt;
}
/* At this point, there shouldn't be any remaining packets. */
MLX5_ASSERT(rxq->decompressed == 0);
/* Process all the CQEs */
nocmp_n = rxq_cq_process_v(rxq, cq, elts, pkts, pkts_n, err, &comp_idx);
/* If no new CQE seen, return without updating cq_db. */
if (unlikely(!nocmp_n && comp_idx == MLX5_VPMD_DESCS_PER_LOOP)) {
*no_cq = true;
return rcvd_pkt;
}
/* Update the consumer indexes for non-compressed CQEs. */
MLX5_ASSERT(nocmp_n <= pkts_n);
rxq->cq_ci += nocmp_n;
rxq->rq_pi += nocmp_n;
rcvd_pkt += nocmp_n;
/* Decompress the last CQE if compressed. */
if (comp_idx < MLX5_VPMD_DESCS_PER_LOOP) {
MLX5_ASSERT(comp_idx == (nocmp_n % MLX5_VPMD_DESCS_PER_LOOP));
rxq->decompressed = rxq_cq_decompress_v(rxq, &cq[nocmp_n],
&elts[nocmp_n]);
rxq->cq_ci += rxq->decompressed;
/* Return more packets if needed. */
if (nocmp_n < pkts_n) {
uint16_t n = rxq->decompressed;
n = RTE_MIN(n, pkts_n - nocmp_n);
rxq_copy_mbuf_v(&(*rxq->elts)[rxq->rq_pi & e_mask],
&pkts[nocmp_n], n);
rxq->rq_pi += n;
rcvd_pkt += n;
rxq->decompressed -= n;
}
}
rte_io_wmb();
*rxq->cq_db = rte_cpu_to_be_32(rxq->cq_ci);
*no_cq = !rcvd_pkt;
return rcvd_pkt;
}
/**
* DPDK callback for vectorized RX.
*
* @param dpdk_rxq
* Generic pointer to RX queue structure.
* @param[out] pkts
* Array to store received packets.
* @param pkts_n
* Maximum number of packets in array.
*
* @return
* Number of packets successfully received (<= pkts_n).
*/
uint16_t
mlx5_rx_burst_vec(void *dpdk_rxq, struct rte_mbuf **pkts, uint16_t pkts_n)
{
struct mlx5_rxq_data *rxq = dpdk_rxq;
uint16_t nb_rx = 0;
uint16_t tn = 0;
uint64_t err = 0;
bool no_cq = false;
do {
nb_rx = rxq_burst_v(rxq, pkts + tn, pkts_n - tn,
&err, &no_cq);
if (unlikely(err | rxq->err_state))
nb_rx = rxq_handle_pending_error(rxq, pkts + tn, nb_rx);
tn += nb_rx;
if (unlikely(no_cq))
break;
} while (tn != pkts_n);
return tn;
}
/**
* Receive burst of packets. An errored completion also consumes a mbuf, but the
* packet_type is set to be RTE_PTYPE_ALL_MASK. Marked mbufs should be freed
* before returning to application.
*
* @param rxq
* Pointer to RX queue structure.
* @param[out] pkts
* Array to store received packets.
* @param pkts_n
* Maximum number of packets in array.
* @param[out] err
* Pointer to a flag. Set non-zero value if pkts array has at least one error
* packet to handle.
* @param[out] no_cq
* Pointer to a boolean. Set true if no new CQE seen.
*
* @return
* Number of packets received including errors (<= pkts_n).
*/
static inline uint16_t
rxq_burst_mprq_v(struct mlx5_rxq_data *rxq, struct rte_mbuf **pkts,
uint16_t pkts_n, uint64_t *err, bool *no_cq)
{
const uint16_t q_n = 1 << rxq->cqe_n;
const uint16_t q_mask = q_n - 1;
const uint16_t wqe_n = 1 << rxq->elts_n;
const uint32_t strd_n = 1 << rxq->strd_num_n;
const uint32_t elts_n = wqe_n * strd_n;
const uint32_t elts_mask = elts_n - 1;
volatile struct mlx5_cqe *cq;
struct rte_mbuf **elts;
uint64_t comp_idx = MLX5_VPMD_DESCS_PER_LOOP;
uint16_t nocmp_n = 0;
uint16_t rcvd_pkt = 0;
uint16_t cp_pkt = 0;
unsigned int cq_idx = rxq->cq_ci & q_mask;
unsigned int elts_idx;
MLX5_ASSERT(rxq->sges_n == 0);
cq = &(*rxq->cqes)[cq_idx];
rte_prefetch0(cq);
rte_prefetch0(cq + 1);
rte_prefetch0(cq + 2);
rte_prefetch0(cq + 3);
pkts_n = RTE_MIN(pkts_n, MLX5_VPMD_RX_MAX_BURST);
mlx5_rx_mprq_replenish_bulk_mbuf(rxq);
/* See if there're unreturned mbufs from compressed CQE. */
rcvd_pkt = rxq->decompressed;
if (rcvd_pkt > 0) {
rcvd_pkt = RTE_MIN(rcvd_pkt, pkts_n);
cp_pkt = rxq_copy_mprq_mbuf_v(rxq, pkts, rcvd_pkt);
rxq->decompressed -= rcvd_pkt;
pkts += cp_pkt;
}
elts_idx = rxq->rq_pi & elts_mask;
elts = &(*rxq->elts)[elts_idx];
/* Not to overflow pkts array. */
pkts_n = RTE_ALIGN_FLOOR(pkts_n - cp_pkt, MLX5_VPMD_DESCS_PER_LOOP);
/* Not to cross queue end. */
pkts_n = RTE_MIN(pkts_n, elts_n - elts_idx);
pkts_n = RTE_MIN(pkts_n, q_n - cq_idx);
/* Not to move past the allocated mbufs. */
pkts_n = RTE_MIN(pkts_n, rxq->elts_ci - rxq->rq_pi);
if (!pkts_n) {
*no_cq = !cp_pkt;
return cp_pkt;
}
/* At this point, there shouldn't be any remaining packets. */
MLX5_ASSERT(rxq->decompressed == 0);
/* Process all the CQEs */
nocmp_n = rxq_cq_process_v(rxq, cq, elts, pkts, pkts_n, err, &comp_idx);
/* If no new CQE seen, return without updating cq_db. */
if (unlikely(!nocmp_n && comp_idx == MLX5_VPMD_DESCS_PER_LOOP)) {
*no_cq = true;
return cp_pkt;
}
/* Update the consumer indexes for non-compressed CQEs. */
MLX5_ASSERT(nocmp_n <= pkts_n);
cp_pkt = rxq_copy_mprq_mbuf_v(rxq, pkts, nocmp_n);
rcvd_pkt += cp_pkt;
/* Decompress the last CQE if compressed. */
if (comp_idx < MLX5_VPMD_DESCS_PER_LOOP) {
MLX5_ASSERT(comp_idx == (nocmp_n % MLX5_VPMD_DESCS_PER_LOOP));
rxq->decompressed = rxq_cq_decompress_v(rxq, &cq[nocmp_n],
&elts[nocmp_n]);
/* Return more packets if needed. */
if (nocmp_n < pkts_n) {
uint16_t n = rxq->decompressed;
n = RTE_MIN(n, pkts_n - nocmp_n);
cp_pkt = rxq_copy_mprq_mbuf_v(rxq, &pkts[cp_pkt], n);
rcvd_pkt += cp_pkt;
rxq->decompressed -= n;
}
}
*no_cq = !rcvd_pkt;
return rcvd_pkt;
}
/**
* DPDK callback for vectorized MPRQ RX.
*
* @param dpdk_rxq
* Generic pointer to RX queue structure.
* @param[out] pkts
* Array to store received packets.
* @param pkts_n
* Maximum number of packets in array.
*
* @return
* Number of packets successfully received (<= pkts_n).
*/
uint16_t
mlx5_rx_burst_mprq_vec(void *dpdk_rxq, struct rte_mbuf **pkts, uint16_t pkts_n)
{
struct mlx5_rxq_data *rxq = dpdk_rxq;
uint16_t nb_rx = 0;
uint16_t tn = 0;
uint64_t err = 0;
bool no_cq = false;
do {
nb_rx = rxq_burst_mprq_v(rxq, pkts + tn, pkts_n - tn,
&err, &no_cq);
if (unlikely(err | rxq->err_state))
nb_rx = rxq_handle_pending_error(rxq, pkts + tn, nb_rx);
tn += nb_rx;
if (unlikely(no_cq))
break;
} while (tn != pkts_n);
return tn;
}
/**
* Check a RX queue can support vectorized RX.
*
* @param rxq
* Pointer to RX queue.
*
* @return
* 1 if supported, negative errno value if not.
*/
int __rte_cold
mlx5_rxq_check_vec_support(struct mlx5_rxq_data *rxq)
{
struct mlx5_rxq_ctrl *ctrl =
container_of(rxq, struct mlx5_rxq_ctrl, rxq);
if (!ctrl->priv->config.rx_vec_en || rxq->sges_n != 0)
return -ENOTSUP;
if (rxq->lro)
return -ENOTSUP;
return 1;
}
/**
* Check a device can support vectorized RX.
*
* @param dev
* Pointer to Ethernet device.
*
* @return
* 1 if supported, negative errno value if not.
*/
int __rte_cold
mlx5_check_vec_rx_support(struct rte_eth_dev *dev)
{
struct mlx5_priv *priv = dev->data->dev_private;
uint32_t i;
if (rte_vect_get_max_simd_bitwidth() < RTE_VECT_SIMD_128)
return -ENOTSUP;
if (!priv->config.rx_vec_en)
return -ENOTSUP;
/* All the configured queues should support. */
for (i = 0; i < priv->rxqs_n; ++i) {
struct mlx5_rxq_data *rxq = (*priv->rxqs)[i];
if (!rxq)
continue;
if (mlx5_rxq_check_vec_support(rxq) < 0)
break;
}
if (i != priv->rxqs_n)
return -ENOTSUP;
return 1;
}
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