Date: Fri, 20 May 2016 06:54:58 +0000 (UTC) From: Hans Petter Selasky <hselasky@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r300277 - head/sys/dev/mlx5/mlx5_en Message-ID: <201605200654.u4K6swd0090981@repo.freebsd.org>
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Author: hselasky Date: Fri May 20 06:54:58 2016 New Revision: 300277 URL: https://svnweb.freebsd.org/changeset/base/300277 Log: Implement TX completion event interleaving. This patch implements a sysctl which allows setting a factor, N, for how many work queue elements can be generated before requiring a completion event. When a completion event happens the code simulates N completion events instead of only one. When draining a transmit queue, N-1 NOPs are transmitted at most, to force generation of the final completion event. Further a timer is running every HZ ticks to flush any remaining data off the transmit queue when the tx_completion_fact > 1. The goal of this feature is to reduce the PCI bandwidth needed when transmitting data. Sponsored by: Mellanox Technologies Tested by: Netflix MFC after: 1 week Modified: head/sys/dev/mlx5/mlx5_en/en.h head/sys/dev/mlx5/mlx5_en/mlx5_en_ethtool.c head/sys/dev/mlx5/mlx5_en/mlx5_en_main.c head/sys/dev/mlx5/mlx5_en/mlx5_en_tx.c Modified: head/sys/dev/mlx5/mlx5_en/en.h ============================================================================== --- head/sys/dev/mlx5/mlx5_en/en.h Fri May 20 06:47:42 2016 (r300276) +++ head/sys/dev/mlx5/mlx5_en/en.h Fri May 20 06:54:58 2016 (r300277) @@ -391,6 +391,8 @@ struct mlx5e_params { m(+1, u64 tx_coalesce_usecs, "tx_coalesce_usecs", "Limit in usec for joining tx packets") \ m(+1, u64 tx_coalesce_pkts, "tx_coalesce_pkts", "Maximum number of tx packets to join") \ m(+1, u64 tx_coalesce_mode, "tx_coalesce_mode", "0: EQE mode 1: CQE mode") \ + m(+1, u64 tx_completion_fact, "tx_completion_fact", "1..MAX: Completion event ratio") \ + m(+1, u64 tx_completion_fact_max, "tx_completion_fact_max", "Maximum completion event ratio") \ m(+1, u64 hw_lro, "hw_lro", "set to enable hw_lro") \ m(+1, u64 cqe_zipping, "cqe_zipping", "0 : CQE zipping disabled") @@ -496,6 +498,13 @@ struct mlx5e_sq { /* dirtied @xmit */ u16 pc __aligned(MLX5E_CACHELINE_SIZE); u16 bf_offset; + u16 cev_counter; /* completion event counter */ + u16 cev_factor; /* completion event factor */ + u32 cev_next_state; /* next completion event state */ +#define MLX5E_CEV_STATE_INITIAL 0 /* timer not started */ +#define MLX5E_CEV_STATE_SEND_NOPS 1 /* send NOPs */ +#define MLX5E_CEV_STATE_HOLD_NOPS 2 /* don't send NOPs yet */ + struct callout cev_callout; struct mlx5e_sq_stats stats; struct mlx5e_cq cq; @@ -787,6 +796,7 @@ void mlx5e_create_stats(struct sysctl_ct struct sysctl_oid_list *, const char *, const char **, unsigned, u64 *); void mlx5e_send_nop(struct mlx5e_sq *, u32, bool); +void mlx5e_sq_cev_timeout(void *); int mlx5e_refresh_channel_params(struct mlx5e_priv *); #endif /* _MLX5_EN_H_ */ Modified: head/sys/dev/mlx5/mlx5_en/mlx5_en_ethtool.c ============================================================================== --- head/sys/dev/mlx5/mlx5_en/mlx5_en_ethtool.c Fri May 20 06:47:42 2016 (r300276) +++ head/sys/dev/mlx5/mlx5_en/mlx5_en_ethtool.c Fri May 20 06:54:58 2016 (r300277) @@ -48,6 +48,42 @@ mlx5e_create_stats(struct sysctl_ctx_lis } } +static void +mlx5e_ethtool_sync_tx_completion_fact(struct mlx5e_priv *priv) +{ + /* + * Limit the maximum distance between completion events to + * half of the currently set TX queue size. + * + * The maximum number of queue entries a single IP packet can + * consume is given by MLX5_SEND_WQE_MAX_WQEBBS. + * + * The worst case max value is then given as below: + */ + uint64_t max = priv->params_ethtool.tx_queue_size / + (2 * MLX5_SEND_WQE_MAX_WQEBBS); + + /* + * Update the maximum completion factor value in case the + * tx_queue_size field changed. Ensure we don't overflow + * 16-bits. + */ + if (max < 1) + max = 1; + else if (max > 65535) + max = 65535; + priv->params_ethtool.tx_completion_fact_max = max; + + /* + * Verify that the current TX completion factor is within the + * given limits: + */ + if (priv->params_ethtool.tx_completion_fact < 1) + priv->params_ethtool.tx_completion_fact = 1; + else if (priv->params_ethtool.tx_completion_fact > max) + priv->params_ethtool.tx_completion_fact = max; +} + static int mlx5e_ethtool_handler(SYSCTL_HANDLER_ARGS) { @@ -206,6 +242,14 @@ mlx5e_ethtool_handler(SYSCTL_HANDLER_ARG priv->params_ethtool.cqe_zipping = 0; } } + + if (&priv->params_ethtool.arg[arg2] == + &priv->params_ethtool.tx_completion_fact || + &priv->params_ethtool.arg[arg2] == + &priv->params_ethtool.tx_queue_size) { + /* verify parameter */ + mlx5e_ethtool_sync_tx_completion_fact(priv); + } if (was_opened) mlx5e_open_locked(priv->ifp); done: @@ -475,6 +519,7 @@ mlx5e_create_ethtool(struct mlx5e_priv * priv->params_ethtool.tx_coalesce_pkts = priv->params.tx_cq_moderation_pkts; priv->params_ethtool.hw_lro = priv->params.hw_lro_en; priv->params_ethtool.cqe_zipping = priv->params.cqe_zipping_en; + mlx5e_ethtool_sync_tx_completion_fact(priv); /* create root node */ node = SYSCTL_ADD_NODE(&priv->sysctl_ctx, Modified: head/sys/dev/mlx5/mlx5_en/mlx5_en_main.c ============================================================================== --- head/sys/dev/mlx5/mlx5_en/mlx5_en_main.c Fri May 20 06:47:42 2016 (r300276) +++ head/sys/dev/mlx5/mlx5_en/mlx5_en_main.c Fri May 20 06:54:58 2016 (r300277) @@ -1185,24 +1185,82 @@ err_destroy_sq: } static void -mlx5e_close_sq(struct mlx5e_sq *sq) +mlx5e_sq_send_nops_locked(struct mlx5e_sq *sq, int can_sleep) { - - /* ensure hw is notified of all pending wqes */ - if (mlx5e_sq_has_room_for(sq, 1)) + /* fill up remainder with NOPs */ + while (sq->cev_counter != 0) { + while (!mlx5e_sq_has_room_for(sq, 1)) { + if (can_sleep != 0) { + mtx_unlock(&sq->lock); + msleep(4); + mtx_lock(&sq->lock); + } else { + goto done; + } + } mlx5e_send_nop(sq, 1, true); + } +done: + return; +} - mlx5e_modify_sq(sq, MLX5_SQC_STATE_RDY, MLX5_SQC_STATE_ERR); +void +mlx5e_sq_cev_timeout(void *arg) +{ + struct mlx5e_sq *sq = arg; + + mtx_assert(&sq->lock, MA_OWNED); + + /* check next state */ + switch (sq->cev_next_state) { + case MLX5E_CEV_STATE_SEND_NOPS: + /* fill TX ring with NOPs, if any */ + mlx5e_sq_send_nops_locked(sq, 0); + + /* check if completed */ + if (sq->cev_counter == 0) { + sq->cev_next_state = MLX5E_CEV_STATE_INITIAL; + return; + } + break; + default: + /* send NOPs on next timeout */ + sq->cev_next_state = MLX5E_CEV_STATE_SEND_NOPS; + break; + } + + /* restart timer */ + callout_reset_curcpu(&sq->cev_callout, hz, mlx5e_sq_cev_timeout, sq); } static void mlx5e_close_sq_wait(struct mlx5e_sq *sq) { + + mtx_lock(&sq->lock); + /* teardown event factor timer, if any */ + sq->cev_next_state = MLX5E_CEV_STATE_HOLD_NOPS; + callout_stop(&sq->cev_callout); + + /* send dummy NOPs in order to flush the transmit ring */ + mlx5e_sq_send_nops_locked(sq, 1); + mtx_unlock(&sq->lock); + + /* make sure it is safe to free the callout */ + callout_drain(&sq->cev_callout); + + /* error out remaining requests */ + mlx5e_modify_sq(sq, MLX5_SQC_STATE_RDY, MLX5_SQC_STATE_ERR); + /* wait till SQ is empty */ + mtx_lock(&sq->lock); while (sq->cc != sq->pc) { + mtx_unlock(&sq->lock); msleep(4); sq->cq.mcq.comp(&sq->cq.mcq); + mtx_lock(&sq->lock); } + mtx_unlock(&sq->lock); mlx5e_disable_sq(sq); mlx5e_destroy_sq(sq); @@ -1412,24 +1470,13 @@ mlx5e_open_sqs(struct mlx5e_channel *c, return (0); err_close_sqs: - for (tc--; tc >= 0; tc--) { - mlx5e_close_sq(&c->sq[tc]); + for (tc--; tc >= 0; tc--) mlx5e_close_sq_wait(&c->sq[tc]); - } return (err); } static void -mlx5e_close_sqs(struct mlx5e_channel *c) -{ - int tc; - - for (tc = 0; tc < c->num_tc; tc++) - mlx5e_close_sq(&c->sq[tc]); -} - -static void mlx5e_close_sqs_wait(struct mlx5e_channel *c) { int tc; @@ -1446,9 +1493,19 @@ mlx5e_chan_mtx_init(struct mlx5e_channel mtx_init(&c->rq.mtx, "mlx5rx", MTX_NETWORK_LOCK, MTX_DEF); for (tc = 0; tc < c->num_tc; tc++) { - mtx_init(&c->sq[tc].lock, "mlx5tx", MTX_NETWORK_LOCK, MTX_DEF); - mtx_init(&c->sq[tc].comp_lock, "mlx5comp", MTX_NETWORK_LOCK, + struct mlx5e_sq *sq = c->sq + tc; + + mtx_init(&sq->lock, "mlx5tx", MTX_NETWORK_LOCK, MTX_DEF); + mtx_init(&sq->comp_lock, "mlx5comp", MTX_NETWORK_LOCK, MTX_DEF); + + callout_init_mtx(&sq->cev_callout, &sq->lock, 0); + + sq->cev_factor = c->priv->params_ethtool.tx_completion_fact; + + /* ensure the TX completion event factor is not zero */ + if (sq->cev_factor == 0) + sq->cev_factor = 1; } } @@ -1529,7 +1586,6 @@ mlx5e_open_channel(struct mlx5e_priv *pr return (0); err_close_sqs: - mlx5e_close_sqs(c); mlx5e_close_sqs_wait(c); err_close_rx_cq: @@ -1554,7 +1610,6 @@ mlx5e_close_channel(struct mlx5e_channel if (c == NULL) return; mlx5e_close_rq(&c->rq); - mlx5e_close_sqs(c); } static void Modified: head/sys/dev/mlx5/mlx5_en/mlx5_en_tx.c ============================================================================== --- head/sys/dev/mlx5/mlx5_en/mlx5_en_tx.c Fri May 20 06:47:42 2016 (r300276) +++ head/sys/dev/mlx5/mlx5_en/mlx5_en_tx.c Fri May 20 06:54:58 2016 (r300277) @@ -28,6 +28,18 @@ #include "en.h" #include <machine/atomic.h> +static inline bool +mlx5e_do_send_cqe(struct mlx5e_sq *sq) +{ + sq->cev_counter++; + /* interleave the CQEs */ + if (sq->cev_counter >= sq->cev_factor) { + sq->cev_counter = 0; + return (1); + } + return (0); +} + void mlx5e_send_nop(struct mlx5e_sq *sq, u32 ds_cnt, bool notify_hw) { @@ -38,7 +50,10 @@ mlx5e_send_nop(struct mlx5e_sq *sq, u32 wqe->ctrl.opmod_idx_opcode = cpu_to_be32((sq->pc << 8) | MLX5_OPCODE_NOP); wqe->ctrl.qpn_ds = cpu_to_be32((sq->sqn << 8) | ds_cnt); - wqe->ctrl.fm_ce_se = MLX5_WQE_CTRL_CQ_UPDATE; + if (mlx5e_do_send_cqe(sq)) + wqe->ctrl.fm_ce_se = MLX5_WQE_CTRL_CQ_UPDATE; + else + wqe->ctrl.fm_ce_se = 0; sq->mbuf[pi].mbuf = NULL; sq->mbuf[pi].num_bytes = 0; @@ -340,7 +355,10 @@ skip_dma: wqe->ctrl.opmod_idx_opcode = cpu_to_be32((sq->pc << 8) | opcode); wqe->ctrl.qpn_ds = cpu_to_be32((sq->sqn << 8) | ds_cnt); - wqe->ctrl.fm_ce_se = MLX5_WQE_CTRL_CQ_UPDATE; + if (mlx5e_do_send_cqe(sq)) + wqe->ctrl.fm_ce_se = MLX5_WQE_CTRL_CQ_UPDATE; + else + wqe->ctrl.fm_ce_se = 0; /* Store pointer to mbuf */ sq->mbuf[pi].mbuf = mb; @@ -374,9 +392,10 @@ mlx5e_poll_tx_cq(struct mlx5e_sq *sq, in */ sqcc = sq->cc; - while (budget--) { + while (budget > 0) { struct mlx5_cqe64 *cqe; struct mbuf *mb; + u16 x; u16 ci; cqe = mlx5e_get_cqe(&sq->cq); @@ -385,24 +404,29 @@ mlx5e_poll_tx_cq(struct mlx5e_sq *sq, in mlx5_cqwq_pop(&sq->cq.wq); - ci = sqcc & sq->wq.sz_m1; - mb = sq->mbuf[ci].mbuf; - sq->mbuf[ci].mbuf = NULL; /* Safety clear */ + /* update budget according to the event factor */ + budget -= sq->cev_factor; - if (mb == NULL) { - if (sq->mbuf[ci].num_bytes == 0) { - /* NOP */ - sq->stats.nop++; - } - } else { - bus_dmamap_sync(sq->dma_tag, sq->mbuf[ci].dma_map, - BUS_DMASYNC_POSTWRITE); - bus_dmamap_unload(sq->dma_tag, sq->mbuf[ci].dma_map); + for (x = 0; x != sq->cev_factor; x++) { + ci = sqcc & sq->wq.sz_m1; + mb = sq->mbuf[ci].mbuf; + sq->mbuf[ci].mbuf = NULL; /* Safety clear */ + + if (mb == NULL) { + if (sq->mbuf[ci].num_bytes == 0) { + /* NOP */ + sq->stats.nop++; + } + } else { + bus_dmamap_sync(sq->dma_tag, sq->mbuf[ci].dma_map, + BUS_DMASYNC_POSTWRITE); + bus_dmamap_unload(sq->dma_tag, sq->mbuf[ci].dma_map); - /* Free transmitted mbuf */ - m_freem(mb); + /* Free transmitted mbuf */ + m_freem(mb); + } + sqcc += sq->mbuf[ci].num_wqebbs; } - sqcc += sq->mbuf[ci].num_wqebbs; } mlx5_cqwq_update_db_record(&sq->cq.wq); @@ -450,6 +474,18 @@ mlx5e_xmit_locked(struct ifnet *ifp, str if ((ifp->if_drv_flags & IFF_DRV_RUNNING) == 0) break; } + /* + * Check if we need to start the event timer which flushes the + * transmit ring on timeout: + */ + if (unlikely(sq->cev_next_state == MLX5E_CEV_STATE_INITIAL && + sq->cev_factor != 1)) { + /* start the timer */ + mlx5e_sq_cev_timeout(sq); + } else { + /* don't send NOPs yet */ + sq->cev_next_state = MLX5E_CEV_STATE_HOLD_NOPS; + } return (err); }
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