[dpdk-dev] [PATCH v2 1/3] net/af_xdp: enable zero copy by extbuf
William Tu
u9012063 at gmail.com
Tue Jun 11 18:16:45 CEST 2019
On Thu, May 30, 2019 at 2:16 AM Xiaolong Ye <xiaolong.ye at intel.com> wrote:
>
> Implement zero copy of af_xdp pmd through mbuf's external memory
> mechanism to achieve high performance.
>
> This patch also provides a new parameter "pmd_zero_copy" for user, so they
> can choose to enable zero copy of af_xdp pmd or not.
>
> To be clear, "zero copy" here is different from the "zero copy mode" of
> AF_XDP, it is about zero copy between af_xdp umem and mbuf used in dpdk
> application.
>
> Suggested-by: Varghese Vipin <vipin.varghese at intel.com>
> Suggested-by: Tummala Sivaprasad <sivaprasad.tummala at intel.com>
> Suggested-by: Olivier Matz <olivier.matz at 6wind.com>
> Signed-off-by: Xiaolong Ye <xiaolong.ye at intel.com>
> ---
> doc/guides/nics/af_xdp.rst | 1 +
> drivers/net/af_xdp/rte_eth_af_xdp.c | 104 +++++++++++++++++++++-------
> 2 files changed, 79 insertions(+), 26 deletions(-)
>
> diff --git a/doc/guides/nics/af_xdp.rst b/doc/guides/nics/af_xdp.rst
> index 175038153..0bd4239fe 100644
> --- a/doc/guides/nics/af_xdp.rst
> +++ b/doc/guides/nics/af_xdp.rst
> @@ -28,6 +28,7 @@ The following options can be provided to set up an af_xdp port in DPDK.
>
> * ``iface`` - name of the Kernel interface to attach to (required);
> * ``queue`` - netdev queue id (optional, default 0);
> +* ``pmd_zero_copy`` - enable zero copy or not (optional, default 0);
>
> Prerequisites
> -------------
> diff --git a/drivers/net/af_xdp/rte_eth_af_xdp.c b/drivers/net/af_xdp/rte_eth_af_xdp.c
> index 35c72272c..014cd5691 100644
> --- a/drivers/net/af_xdp/rte_eth_af_xdp.c
> +++ b/drivers/net/af_xdp/rte_eth_af_xdp.c
> @@ -70,6 +70,7 @@ struct xsk_umem_info {
> struct xsk_umem *umem;
> struct rte_ring *buf_ring;
> const struct rte_memzone *mz;
> + int pmd_zc;
> };
>
> struct rx_stats {
> @@ -109,8 +110,8 @@ struct pmd_internals {
> int if_index;
> char if_name[IFNAMSIZ];
> uint16_t queue_idx;
> + int pmd_zc;
> struct ether_addr eth_addr;
> - struct xsk_umem_info *umem;
> struct rte_mempool *mb_pool_share;
>
> struct pkt_rx_queue rx_queues[ETH_AF_XDP_MAX_QUEUE_PAIRS];
> @@ -119,10 +120,12 @@ struct pmd_internals {
>
> #define ETH_AF_XDP_IFACE_ARG "iface"
> #define ETH_AF_XDP_QUEUE_IDX_ARG "queue"
> +#define ETH_AF_XDP_PMD_ZC_ARG "pmd_zero_copy"
>
> static const char * const valid_arguments[] = {
> ETH_AF_XDP_IFACE_ARG,
> ETH_AF_XDP_QUEUE_IDX_ARG,
> + ETH_AF_XDP_PMD_ZC_ARG,
> NULL
> };
>
> @@ -166,6 +169,15 @@ reserve_fill_queue(struct xsk_umem_info *umem, uint16_t reserve_size)
> return 0;
> }
>
> +static void
> +umem_buf_release_to_fq(void *addr, void *opaque)
> +{
> + struct xsk_umem_info *umem = (struct xsk_umem_info *)opaque;
> + uint64_t umem_addr = (uint64_t)addr - umem->mz->addr_64;
> +
> + rte_ring_enqueue(umem->buf_ring, (void *)umem_addr);
> +}
> +
> static uint16_t
> eth_af_xdp_rx(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
> {
> @@ -175,6 +187,7 @@ eth_af_xdp_rx(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
> struct xsk_ring_prod *fq = &umem->fq;
> uint32_t idx_rx = 0;
> uint32_t free_thresh = fq->size >> 1;
> + int pmd_zc = umem->pmd_zc;
> struct rte_mbuf *mbufs[ETH_AF_XDP_RX_BATCH_SIZE];
> unsigned long dropped = 0;
> unsigned long rx_bytes = 0;
> @@ -197,19 +210,29 @@ eth_af_xdp_rx(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
> uint64_t addr;
> uint32_t len;
> void *pkt;
> + uint16_t buf_len = ETH_AF_XDP_FRAME_SIZE;
> + struct rte_mbuf_ext_shared_info *shinfo;
>
> desc = xsk_ring_cons__rx_desc(rx, idx_rx++);
> addr = desc->addr;
> len = desc->len;
> pkt = xsk_umem__get_data(rxq->umem->mz->addr, addr);
>
> - rte_memcpy(rte_pktmbuf_mtod(mbufs[i], void *), pkt, len);
> + if (pmd_zc) {
> + shinfo = rte_pktmbuf_ext_shinfo_init_helper(pkt,
> + &buf_len, umem_buf_release_to_fq, umem);
> +
> + rte_pktmbuf_attach_extbuf(mbufs[i], pkt, 0, buf_len,
> + shinfo);
> + } else {
> + rte_memcpy(rte_pktmbuf_mtod(mbufs[i], void *),
> + pkt, len);
> + rte_ring_enqueue(umem->buf_ring, (void *)addr);
> + }
> rte_pktmbuf_pkt_len(mbufs[i]) = len;
> rte_pktmbuf_data_len(mbufs[i]) = len;
> rx_bytes += len;
> bufs[i] = mbufs[i];
> -
> - rte_ring_enqueue(umem->buf_ring, (void *)addr);
> }
>
> xsk_ring_cons__release(rx, rcvd);
> @@ -262,12 +285,21 @@ kick_tx(struct pkt_tx_queue *txq)
> pull_umem_cq(umem, ETH_AF_XDP_TX_BATCH_SIZE);
> }
>
> +static inline bool
> +in_umem_range(struct xsk_umem_info *umem, uint64_t addr)
> +{
> + uint64_t mz_base_addr = umem->mz->addr_64;
> +
> + return addr >= mz_base_addr && addr < mz_base_addr + umem->mz->len;
> +}
> +
> static uint16_t
> eth_af_xdp_tx(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
> {
> struct pkt_tx_queue *txq = queue;
> struct xsk_umem_info *umem = txq->pair->umem;
> struct rte_mbuf *mbuf;
> + int pmd_zc = umem->pmd_zc;
> void *addrs[ETH_AF_XDP_TX_BATCH_SIZE];
> unsigned long tx_bytes = 0;
> int i;
> @@ -294,16 +326,26 @@ eth_af_xdp_tx(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
>
> desc = xsk_ring_prod__tx_desc(&txq->tx, idx_tx + i);
> mbuf = bufs[i];
> -
> - desc->addr = (uint64_t)addrs[i];
> desc->len = mbuf->pkt_len;
> - pkt = xsk_umem__get_data(umem->mz->addr,
> - desc->addr);
> - rte_memcpy(pkt, rte_pktmbuf_mtod(mbuf, void *),
> - desc->len);
> - tx_bytes += mbuf->pkt_len;
>
> - rte_pktmbuf_free(mbuf);
> + /*
> + * We need to make sure the external mbuf address is within
> + * current port's umem memzone range
> + */
> + if (pmd_zc && RTE_MBUF_HAS_EXTBUF(mbuf) &&
> + in_umem_range(umem, (uint64_t)mbuf->buf_addr)) {
> + desc->addr = (uint64_t)mbuf->buf_addr -
> + umem->mz->addr_64;
> + mbuf->buf_addr = xsk_umem__get_data(umem->mz->addr,
> + (uint64_t)addrs[i]);
> + } else {
> + desc->addr = (uint64_t)addrs[i];
> + pkt = xsk_umem__get_data(umem->mz->addr,
> + desc->addr);
> + rte_memcpy(pkt, rte_pktmbuf_mtod(mbuf, void *),
> + desc->len);
> + }
> + tx_bytes += mbuf->pkt_len;
> }
>
> xsk_ring_prod__submit(&txq->tx, nb_pkts);
> @@ -313,6 +355,9 @@ eth_af_xdp_tx(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
> txq->stats.tx_pkts += nb_pkts;
> txq->stats.tx_bytes += tx_bytes;
>
> + for (i = 0; i < nb_pkts; i++)
> + rte_pktmbuf_free(bufs[i]);
> +
Is it ok to free the mbuf here?
If the AF_XDP is running pmd_zc=true, the packet mbuf is still in the tx
ring and might not be sent out yet.
Regards,
William
> return nb_pkts;
> }
>
> @@ -454,18 +499,16 @@ eth_dev_close(struct rte_eth_dev *dev)
> if (rxq->umem == NULL)
> break;
> xsk_socket__delete(rxq->xsk);
> + (void)xsk_umem__delete(rxq->umem->umem);
> + xdp_umem_destroy(rxq->umem);
> }
>
> - (void)xsk_umem__delete(internals->umem->umem);
> -
> /*
> * MAC is not allocated dynamically, setting it to NULL would prevent
> * from releasing it in rte_eth_dev_release_port.
> */
> dev->data->mac_addrs = NULL;
>
> - xdp_umem_destroy(internals->umem);
> -
> remove_xdp_program(internals);
> }
>
> @@ -639,7 +682,7 @@ eth_rx_queue_setup(struct rte_eth_dev *dev,
> goto err;
> }
>
> - internals->umem = rxq->umem;
> + rxq->umem->pmd_zc = internals->pmd_zc;
>
> dev->data->rx_queues[rx_queue_id] = rxq;
> return 0;
> @@ -775,9 +818,8 @@ parse_name_arg(const char *key __rte_unused,
> }
>
> static int
> -parse_parameters(struct rte_kvargs *kvlist,
> - char *if_name,
> - int *queue_idx)
> +parse_parameters(struct rte_kvargs *kvlist, char *if_name, int *queue_idx,
> + int *pmd_zc)
> {
> int ret;
>
> @@ -791,6 +833,11 @@ parse_parameters(struct rte_kvargs *kvlist,
> if (ret < 0)
> goto free_kvlist;
>
> + ret = rte_kvargs_process(kvlist, ETH_AF_XDP_PMD_ZC_ARG,
> + &parse_integer_arg, pmd_zc);
> + if (ret < 0)
> + goto free_kvlist;
> +
> free_kvlist:
> rte_kvargs_free(kvlist);
> return ret;
> @@ -827,9 +874,8 @@ get_iface_info(const char *if_name,
> }
>
> static struct rte_eth_dev *
> -init_internals(struct rte_vdev_device *dev,
> - const char *if_name,
> - int queue_idx)
> +init_internals(struct rte_vdev_device *dev, const char *if_name, int queue_idx,
> + int pmd_zc)
> {
> const char *name = rte_vdev_device_name(dev);
> const unsigned int numa_node = dev->device.numa_node;
> @@ -843,6 +889,7 @@ init_internals(struct rte_vdev_device *dev,
> return NULL;
>
> internals->queue_idx = queue_idx;
> + internals->pmd_zc = pmd_zc;
> strlcpy(internals->if_name, if_name, IFNAMSIZ);
>
> for (i = 0; i < ETH_AF_XDP_MAX_QUEUE_PAIRS; i++) {
> @@ -868,6 +915,9 @@ init_internals(struct rte_vdev_device *dev,
> /* Let rte_eth_dev_close() release the port resources. */
> eth_dev->data->dev_flags |= RTE_ETH_DEV_CLOSE_REMOVE;
>
> + if (internals->pmd_zc)
> + AF_XDP_LOG(INFO, "Zero copy between umem and mbuf enabled.\n");
> +
> return eth_dev;
>
> err:
> @@ -883,6 +933,7 @@ rte_pmd_af_xdp_probe(struct rte_vdev_device *dev)
> int xsk_queue_idx = ETH_AF_XDP_DFLT_QUEUE_IDX;
> struct rte_eth_dev *eth_dev = NULL;
> const char *name;
> + int pmd_zc = 0;
>
> AF_XDP_LOG(INFO, "Initializing pmd_af_xdp for %s\n",
> rte_vdev_device_name(dev));
> @@ -909,7 +960,7 @@ rte_pmd_af_xdp_probe(struct rte_vdev_device *dev)
> if (dev->device.numa_node == SOCKET_ID_ANY)
> dev->device.numa_node = rte_socket_id();
>
> - if (parse_parameters(kvlist, if_name, &xsk_queue_idx) < 0) {
> + if (parse_parameters(kvlist, if_name, &xsk_queue_idx, &pmd_zc) < 0) {
> AF_XDP_LOG(ERR, "Invalid kvargs value\n");
> return -EINVAL;
> }
> @@ -919,7 +970,7 @@ rte_pmd_af_xdp_probe(struct rte_vdev_device *dev)
> return -EINVAL;
> }
>
> - eth_dev = init_internals(dev, if_name, xsk_queue_idx);
> + eth_dev = init_internals(dev, if_name, xsk_queue_idx, pmd_zc);
> if (eth_dev == NULL) {
> AF_XDP_LOG(ERR, "Failed to init internals\n");
> return -1;
> @@ -961,7 +1012,8 @@ static struct rte_vdev_driver pmd_af_xdp_drv = {
> RTE_PMD_REGISTER_VDEV(net_af_xdp, pmd_af_xdp_drv);
> RTE_PMD_REGISTER_PARAM_STRING(net_af_xdp,
> "iface=<string> "
> - "queue=<int> ");
> + "queue=<int> "
> + "pmd_zero_copy=<0|1>");
>
> RTE_INIT(af_xdp_init_log)
> {
> --
> 2.17.1
>
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