From: Intel Date: Wed, 19 Dec 2012 23:00:00 +0000 (+0100) Subject: ixgbe: add an optimised "simple" TX function X-Git-Tag: spdx-start~11340 X-Git-Url: http://git.droids-corp.org/?a=commitdiff_plain;h=39944fdce049f61ea8afef7e6a94837b328f7e82;p=dpdk.git ixgbe: add an optimised "simple" TX function Signed-off-by: Intel --- diff --git a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c old mode 100644 new mode 100755 index ea519735a1..66f3c808d9 --- a/lib/librte_pmd_ixgbe/ixgbe_rxtx.c +++ b/lib/librte_pmd_ixgbe/ixgbe_rxtx.c @@ -79,6 +79,9 @@ #include "ixgbe_ethdev.h" #include "ixgbe/ixgbe_dcb.h" + +#define RTE_PMD_IXGBE_TX_MAX_BURST 32 + #ifdef RTE_LIBRTE_IXGBE_RX_ALLOW_BULK_ALLOC #define RTE_PMD_IXGBE_RX_MAX_BURST 32 #endif @@ -186,11 +189,14 @@ struct igb_tx_queue { uint16_t last_desc_cleaned; /** Total number of TX descriptors ready to be allocated. */ uint16_t nb_tx_free; + uint16_t tx_next_dd; /**< next desc to scan for DD bit */ + uint16_t tx_next_rs; /**< next desc to set RS bit */ uint16_t queue_id; /**< TX queue index. */ uint8_t port_id; /**< Device port identifier. */ uint8_t pthresh; /**< Prefetch threshold register. */ uint8_t hthresh; /**< Host threshold register. */ uint8_t wthresh; /**< Write-back threshold reg. */ + uint32_t txq_flags; /**< Holds flags for this TXq */ uint32_t ctx_curr; /**< Hardware context states. */ /** Hardware context0 history. */ struct ixgbe_advctx_info ctx_cache[IXGBE_CTX_NUM]; @@ -221,6 +227,268 @@ struct igb_tx_queue { * TX functions * **********************************************************************/ + +/* + * The "simple" TX queue functions require that the following + * flags are set when the TX queue is configured: + * - ETH_TXQ_FLAGS_NOMULTSEGS + * - ETH_TXQ_FLAGS_NOVLANOFFL + * - ETH_TXQ_FLAGS_NOXSUMSCTP + * - ETH_TXQ_FLAGS_NOXSUMUDP + * - ETH_TXQ_FLAGS_NOXSUMTCP + * and that the RS bit threshold (tx_rs_thresh) is at least equal to + * RTE_PMD_IXGBE_TX_MAX_BURST. + */ +#define IXGBE_SIMPLE_FLAGS ((uint32_t)ETH_TXQ_FLAGS_NOMULTSEGS | \ + ETH_TXQ_FLAGS_NOOFFLOADS) + +/* + * Check for descriptors with their DD bit set and free mbufs. + * Return the total number of buffers freed. + */ +static inline int +ixgbe_tx_free_bufs(struct igb_tx_queue *txq) +{ + struct igb_tx_entry *txep; + uint32_t status; + int i; + + /* check DD bit on threshold descriptor */ + status = txq->tx_ring[txq->tx_next_dd].wb.status; + if (! (status & IXGBE_ADVTXD_STAT_DD)) + return 0; + + /* + * first buffer to free from S/W ring is at index + * tx_next_dd - (tx_rs_thresh-1) + */ + txep = &(txq->sw_ring[txq->tx_next_dd - (txq->tx_rs_thresh - 1)]); + + /* prefetch the mbufs that are about to be freed */ + for (i = 0; i < txq->tx_rs_thresh; ++i) + rte_prefetch0((txep + i)->mbuf); + + /* free buffers one at a time */ + if ((txq->txq_flags & (uint32_t)ETH_TXQ_FLAGS_NOREFCOUNT) != 0) { + for (i = 0; i < txq->tx_rs_thresh; ++i, ++txep) { + rte_mempool_put(txep->mbuf->pool, txep->mbuf); + txep->mbuf = NULL; + } + } else { + for (i = 0; i < txq->tx_rs_thresh; ++i, ++txep) { + rte_pktmbuf_free_seg(txep->mbuf); + txep->mbuf = NULL; + } + } + + /* buffers were freed, update counters */ + txq->nb_tx_free += txq->tx_rs_thresh; + txq->tx_next_dd += txq->tx_rs_thresh; + if (txq->tx_next_dd >= txq->nb_tx_desc) + txq->tx_next_dd = txq->tx_rs_thresh - 1; + + return txq->tx_rs_thresh; +} + +/* + * Populate descriptors with the following info: + * 1.) buffer_addr = phys_addr + headroom + * 2.) cmd_type_len = DCMD_DTYP_FLAGS | pkt_len + * 3.) olinfo_status = pkt_len << PAYLEN_SHIFT + */ + +/* Defines for Tx descriptor */ +#define DCMD_DTYP_FLAGS (IXGBE_ADVTXD_DTYP_DATA |\ + IXGBE_ADVTXD_DCMD_IFCS |\ + IXGBE_ADVTXD_DCMD_DEXT |\ + IXGBE_ADVTXD_DCMD_EOP) + +/* Populate 4 descriptors with data from 4 mbufs */ +static inline void +tx4(volatile union ixgbe_adv_tx_desc *txdp, struct rte_mbuf **pkts) +{ + uint64_t buf_dma_addr; + uint32_t pkt_len; + int i; + + for (i = 0; i < 4; ++i, ++txdp, ++pkts) { + buf_dma_addr = RTE_MBUF_DATA_DMA_ADDR(*pkts); + pkt_len = (*pkts)->pkt.data_len; + + /* write data to descriptor */ + txdp->read.buffer_addr = buf_dma_addr; + txdp->read.cmd_type_len = + ((uint32_t)DCMD_DTYP_FLAGS | pkt_len); + txdp->read.olinfo_status = + (pkt_len << IXGBE_ADVTXD_PAYLEN_SHIFT); + } +} + +/* Populate 1 descriptor with data from 1 mbuf */ +static inline void +tx1(volatile union ixgbe_adv_tx_desc *txdp, struct rte_mbuf **pkts) +{ + uint64_t buf_dma_addr; + uint32_t pkt_len; + + buf_dma_addr = RTE_MBUF_DATA_DMA_ADDR(*pkts); + pkt_len = (*pkts)->pkt.data_len; + + /* write data to descriptor */ + txdp->read.buffer_addr = buf_dma_addr; + txdp->read.cmd_type_len = + ((uint32_t)DCMD_DTYP_FLAGS | pkt_len); + txdp->read.olinfo_status = + (pkt_len << IXGBE_ADVTXD_PAYLEN_SHIFT); +} + +/* + * Fill H/W descriptor ring with mbuf data. + * Copy mbuf pointers to the S/W ring. + */ +static inline void +ixgbe_tx_fill_hw_ring(struct igb_tx_queue *txq, struct rte_mbuf **pkts, + uint16_t nb_pkts) +{ + volatile union ixgbe_adv_tx_desc *txdp = &(txq->tx_ring[txq->tx_tail]); + struct igb_tx_entry *txep = &(txq->sw_ring[txq->tx_tail]); + const int N_PER_LOOP = 4; + const int N_PER_LOOP_MASK = N_PER_LOOP-1; + int mainpart, leftover; + int i, j; + + /* + * Process most of the packets in chunks of N pkts. Any + * leftover packets will get processed one at a time. + */ + mainpart = (nb_pkts & ((uint32_t) ~N_PER_LOOP_MASK)); + leftover = (nb_pkts & ((uint32_t) N_PER_LOOP_MASK)); + for (i = 0; i < mainpart; i += N_PER_LOOP) { + /* Copy N mbuf pointers to the S/W ring */ + for (j = 0; j < N_PER_LOOP; ++j) { + (txep + i + j)->mbuf = *(pkts + i + j); + } + tx4(txdp + i, pkts + i); + } + + if (unlikely(leftover > 0)) { + for (i = 0; i < leftover; ++i) { + (txep + mainpart + i)->mbuf = *(pkts + mainpart + i); + tx1(txdp + mainpart + i, pkts + mainpart + i); + } + } +} + +static inline uint16_t +tx_xmit_pkts(void *tx_queue, struct rte_mbuf **tx_pkts, + uint16_t nb_pkts) +{ + struct igb_tx_queue *txq = (struct igb_tx_queue *)tx_queue; + volatile union ixgbe_adv_tx_desc *tx_r = txq->tx_ring; + uint16_t n = 0; + + /* + * Begin scanning the H/W ring for done descriptors when the + * number of available descriptors drops below tx_free_thresh. For + * each done descriptor, free the associated buffer. + */ + if (txq->nb_tx_free < txq->tx_free_thresh) + ixgbe_tx_free_bufs(txq); + + /* Only use descriptors that are available */ + nb_pkts = RTE_MIN(txq->nb_tx_free, nb_pkts); + if (unlikely(nb_pkts == 0)) + return 0; + + /* Use exactly nb_pkts descriptors */ + txq->nb_tx_free -= nb_pkts; + + /* + * At this point, we know there are enough descriptors in the + * ring to transmit all the packets. This assumes that each + * mbuf contains a single segment, and that no new offloads + * are expected, which would require a new context descriptor. + */ + + /* + * See if we're going to wrap-around. If so, handle the top + * of the descriptor ring first, then do the bottom. If not, + * the processing looks just like the "bottom" part anyway... + */ + if ((txq->tx_tail + nb_pkts) > txq->nb_tx_desc) { + n = txq->nb_tx_desc - txq->tx_tail; + ixgbe_tx_fill_hw_ring(txq, tx_pkts, n); + + /* + * We know that the last descriptor in the ring will need to + * have its RS bit set because tx_rs_thresh has to be + * a divisor of the ring size + */ + tx_r[txq->tx_next_rs].read.cmd_type_len |= + rte_cpu_to_le_32(IXGBE_ADVTXD_DCMD_RS); + txq->tx_next_rs = txq->tx_rs_thresh - 1; + + txq->tx_tail = 0; + } + + /* Fill H/W descriptor ring with mbuf data */ + ixgbe_tx_fill_hw_ring(txq, tx_pkts + n, nb_pkts - n); + txq->tx_tail += (nb_pkts - n); + + /* + * Determine if RS bit should be set + * This is what we actually want: + * if ((txq->tx_tail - 1) >= txq->tx_next_rs) + * but instead of subtracting 1 and doing >=, we can just do + * greater than without subtracting. + */ + if (txq->tx_tail > txq->tx_next_rs) { + tx_r[txq->tx_next_rs].read.cmd_type_len |= + rte_cpu_to_le_32(IXGBE_ADVTXD_DCMD_RS); + txq->tx_next_rs += txq->tx_rs_thresh; + if (txq->tx_next_rs >= txq->nb_tx_desc) + txq->tx_next_rs = txq->tx_rs_thresh - 1; + } + + /* + * Check for wrap-around. This would only happen if we used + * up to the last descriptor in the ring, no more, no less. + */ + if (txq->tx_tail >= txq->nb_tx_desc) + txq->tx_tail = 0; + + /* update tail pointer */ + rte_wmb(); + IXGBE_PCI_REG_WRITE(txq->tdt_reg_addr, txq->tx_tail); + + return nb_pkts; +} + +uint16_t +ixgbe_xmit_pkts_simple(void *tx_queue, struct rte_mbuf **tx_pkts, + uint16_t nb_pkts) +{ + uint16_t nb_tx; + + /* Try to transmit at least chunks of TX_MAX_BURST pkts */ + if (likely(nb_pkts <= RTE_PMD_IXGBE_TX_MAX_BURST)) + return tx_xmit_pkts(tx_queue, tx_pkts, nb_pkts); + + /* transmit more than the max burst, in chunks of TX_MAX_BURST */ + nb_tx = 0; + while (nb_pkts) { + uint16_t ret, n; + n = RTE_MIN(nb_pkts, RTE_PMD_IXGBE_TX_MAX_BURST); + ret = tx_xmit_pkts(tx_queue, &(tx_pkts[nb_tx]), n); + nb_tx += ret; + nb_pkts -= ret; + if (ret < n) + break; + } + + return nb_tx; +} + static inline void ixgbe_set_xmit_ctx(struct igb_tx_queue* txq, volatile struct ixgbe_adv_tx_context_desc *ctx_txd, @@ -1532,6 +1800,9 @@ ixgbe_reset_tx_queue(struct igb_tx_queue *txq) prev = i; } + txq->tx_next_dd = txq->tx_rs_thresh - 1; + txq->tx_next_rs = txq->tx_rs_thresh - 1; + txq->tx_tail = 0; txq->nb_tx_used = 0; /* @@ -1584,6 +1855,7 @@ ixgbe_dev_tx_queue_setup(struct rte_eth_dev *dev, * tx_rs_thresh must be greater than 0. * tx_rs_thresh must be less than the size of the ring minus 2. * tx_rs_thresh must be less than or equal to tx_free_thresh. + * tx_rs_thresh must be a divisor of the ring size. * tx_free_thresh must be greater than 0. * tx_free_thresh must be less than the size of the ring minus 3. * One descriptor in the TX ring is used as a sentinel to avoid a @@ -1616,11 +1888,19 @@ ixgbe_dev_tx_queue_setup(struct rte_eth_dev *dev, "tx_rs_thresh must be less than or equal to " "tx_free_thresh. " "(tx_free_thresh=%u tx_rs_thresh=%u " - "port=%d queue=%d)", + "port=%d queue=%d)\n", tx_free_thresh, tx_rs_thresh, dev->data->port_id, queue_idx); return -(EINVAL); } + if ((nb_desc % tx_rs_thresh) != 0) { + RTE_LOG(ERR, PMD, + "tx_rs_thresh must be a divisor of the" + "number of TX descriptors. " + "(tx_rs_thresh=%u port=%d queue=%d)\n", + tx_rs_thresh, dev->data->port_id, queue_idx); + return -(EINVAL); + } /* * If rs_bit_thresh is greater than 1, then TX WTHRESH should be @@ -1670,6 +1950,7 @@ ixgbe_dev_tx_queue_setup(struct rte_eth_dev *dev, txq->wthresh = tx_conf->tx_thresh.wthresh; txq->queue_id = queue_idx; txq->port_id = dev->data->port_id; + txq->txq_flags = tx_conf->txq_flags; /* * Modification to set VFTDT for virtual function if vf is detected @@ -1697,6 +1978,11 @@ ixgbe_dev_tx_queue_setup(struct rte_eth_dev *dev, dev->data->tx_queues[queue_idx] = txq; + /* Use a simple Tx queue (no offloads, no multi segs) if possible */ + if (((txq->txq_flags & IXGBE_SIMPLE_FLAGS) == IXGBE_SIMPLE_FLAGS) && + (txq->tx_rs_thresh >= RTE_PMD_IXGBE_TX_MAX_BURST)) + dev->tx_pkt_burst = ixgbe_xmit_pkts_simple; + else dev->tx_pkt_burst = ixgbe_xmit_pkts; return (0);