Author: hselasky
Date: Fri Jan 20 15:45:21 2017
New Revision: 312536
URL: https://svnweb.freebsd.org/changeset/base/312536
Log:
Allow transmit packet bufring in software to be disabled.
- Add new sysctl node to control the transmit packet bufring.
- Add optimised version of the transmit routine which output packets
directly to the DMA ring instead of using bufring in case the transmit
lock is congested. This can reduce the number of taskswitches which in
turn influence the overall system CPU usage, depending on the
workload.
- Add " TX" suffix to debug name for transmit mutexes to silence some
witness warnings about aquiring duplicate locks having same name.
MFC after: 1 week
Sponsored by: Mellanox Technologies
Suggested by: gallatin @
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 Jan 20 15:01:04 2017
(r312535)
+++ head/sys/dev/mlx5/mlx5_en/en.h Fri Jan 20 15:45:21 2017
(r312536)
@@ -402,6 +402,7 @@ 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_bufring_disable, "tx_bufring_disable", "0: Enable bufring 1:
Disable bufring") \
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") \
Modified: head/sys/dev/mlx5/mlx5_en/mlx5_en_ethtool.c
==============================================================================
--- head/sys/dev/mlx5/mlx5_en/mlx5_en_ethtool.c Fri Jan 20 15:01:04 2017
(r312535)
+++ head/sys/dev/mlx5/mlx5_en/mlx5_en_ethtool.c Fri Jan 20 15:45:21 2017
(r312536)
@@ -352,6 +352,18 @@ mlx5e_ethtool_handler(SYSCTL_HANDLER_ARG
mlx5e_open_locked(priv->ifp);
break;
+ case MLX5_PARAM_OFFSET(tx_bufring_disable):
+ /* rangecheck input value */
+ priv->params_ethtool.tx_bufring_disable =
+ priv->params_ethtool.tx_bufring_disable ? 1 : 0;
+
+ /* reconfigure the sendqueues, if any */
+ if (was_opened) {
+ mlx5e_close_locked(priv->ifp);
+ mlx5e_open_locked(priv->ifp);
+ }
+ break;
+
case MLX5_PARAM_OFFSET(tx_completion_fact):
/* network interface must be down */
if (was_opened)
Modified: head/sys/dev/mlx5/mlx5_en/mlx5_en_main.c
==============================================================================
--- head/sys/dev/mlx5/mlx5_en/mlx5_en_main.c Fri Jan 20 15:01:04 2017
(r312535)
+++ head/sys/dev/mlx5/mlx5_en/mlx5_en_main.c Fri Jan 20 15:45:21 2017
(r312536)
@@ -439,7 +439,8 @@ mlx5e_update_stats_work(struct work_stru
tso_packets += sq_stats->tso_packets;
tso_bytes += sq_stats->tso_bytes;
tx_queue_dropped += sq_stats->dropped;
- tx_queue_dropped += sq_br->br_drops;
+ if (sq_br != NULL)
+ tx_queue_dropped += sq_br->br_drops;
tx_defragged += sq_stats->defragged;
tx_offload_none += sq_stats->csum_offload_none;
}
@@ -987,34 +988,37 @@ mlx5e_create_sq(struct mlx5e_channel *c,
sq->priv = priv;
sq->tc = tc;
- sq->br = buf_ring_alloc(MLX5E_SQ_TX_QUEUE_SIZE, M_MLX5EN,
- M_WAITOK, &sq->lock);
- if (sq->br == NULL) {
- if_printf(c->ifp, "%s: Failed allocating sq drbr buffer\n",
- __func__);
- err = -ENOMEM;
- goto err_free_sq_db;
- }
-
- sq->sq_tq = taskqueue_create_fast("mlx5e_que", M_WAITOK,
- taskqueue_thread_enqueue, &sq->sq_tq);
- if (sq->sq_tq == NULL) {
- if_printf(c->ifp, "%s: Failed allocating taskqueue\n",
- __func__);
- err = -ENOMEM;
- goto err_free_drbr;
- }
+ /* check if we should allocate a second packet buffer */
+ if (priv->params_ethtool.tx_bufring_disable == 0) {
+ sq->br = buf_ring_alloc(MLX5E_SQ_TX_QUEUE_SIZE, M_MLX5EN,
+ M_WAITOK, &sq->lock);
+ if (sq->br == NULL) {
+ if_printf(c->ifp, "%s: Failed allocating sq drbr
buffer\n",
+ __func__);
+ err = -ENOMEM;
+ goto err_free_sq_db;
+ }
+
+ sq->sq_tq = taskqueue_create_fast("mlx5e_que", M_WAITOK,
+ taskqueue_thread_enqueue, &sq->sq_tq);
+ if (sq->sq_tq == NULL) {
+ if_printf(c->ifp, "%s: Failed allocating taskqueue\n",
+ __func__);
+ err = -ENOMEM;
+ goto err_free_drbr;
+ }
- TASK_INIT(&sq->sq_task, 0, mlx5e_tx_que, sq);
+ TASK_INIT(&sq->sq_task, 0, mlx5e_tx_que, sq);
#ifdef RSS
- cpu_id = rss_getcpu(c->ix % rss_getnumbuckets());
- CPU_SETOF(cpu_id, &cpu_mask);
- taskqueue_start_threads_cpuset(&sq->sq_tq, 1, PI_NET, &cpu_mask,
- "%s TX SQ%d.%d CPU%d", c->ifp->if_xname, c->ix, tc, cpu_id);
+ cpu_id = rss_getcpu(c->ix % rss_getnumbuckets());
+ CPU_SETOF(cpu_id, &cpu_mask);
+ taskqueue_start_threads_cpuset(&sq->sq_tq, 1, PI_NET, &cpu_mask,
+ "%s TX SQ%d.%d CPU%d", c->ifp->if_xname, c->ix, tc, cpu_id);
#else
- taskqueue_start_threads(&sq->sq_tq, 1, PI_NET,
- "%s TX SQ%d.%d", c->ifp->if_xname, c->ix, tc);
+ taskqueue_start_threads(&sq->sq_tq, 1, PI_NET,
+ "%s TX SQ%d.%d", c->ifp->if_xname, c->ix, tc);
#endif
+ }
snprintf(buffer, sizeof(buffer), "txstat%dtc%d", c->ix, tc);
mlx5e_create_stats(&sq->stats.ctx, SYSCTL_CHILDREN(priv->sysctl_ifnet),
buffer, mlx5e_sq_stats_desc, MLX5E_SQ_STATS_NUM,
@@ -1047,9 +1051,12 @@ mlx5e_destroy_sq(struct mlx5e_sq *sq)
mlx5e_free_sq_db(sq);
mlx5_wq_destroy(&sq->wq_ctrl);
mlx5_unmap_free_uar(sq->priv->mdev, &sq->uar);
- taskqueue_drain(sq->sq_tq, &sq->sq_task);
- taskqueue_free(sq->sq_tq);
- buf_ring_free(sq->br, M_MLX5EN);
+ if (sq->sq_tq != NULL) {
+ taskqueue_drain(sq->sq_tq, &sq->sq_task);
+ taskqueue_free(sq->sq_tq);
+ }
+ if (sq->br != NULL)
+ buf_ring_free(sq->br, M_MLX5EN);
}
int
@@ -1497,9 +1504,10 @@ mlx5e_chan_mtx_init(struct mlx5e_channel
for (tc = 0; tc < c->num_tc; tc++) {
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);
+ mtx_init(&sq->lock, "mlx5tx",
+ MTX_NETWORK_LOCK " TX", MTX_DEF);
+ mtx_init(&sq->comp_lock, "mlx5comp",
+ MTX_NETWORK_LOCK " TX", MTX_DEF);
callout_init_mtx(&sq->cev_callout, &sq->lock, 0);
Modified: head/sys/dev/mlx5/mlx5_en/mlx5_en_tx.c
==============================================================================
--- head/sys/dev/mlx5/mlx5_en/mlx5_en_tx.c Fri Jan 20 15:01:04 2017
(r312535)
+++ head/sys/dev/mlx5/mlx5_en/mlx5_en_tx.c Fri Jan 20 15:45:21 2017
(r312536)
@@ -439,7 +439,8 @@ mlx5e_poll_tx_cq(struct mlx5e_sq *sq, in
sq->cc = sqcc;
- if (atomic_cmpset_int(&sq->queue_state, MLX5E_SQ_FULL, MLX5E_SQ_READY))
+ if (sq->sq_tq != NULL &&
+ atomic_cmpset_int(&sq->queue_state, MLX5E_SQ_FULL, MLX5E_SQ_READY))
taskqueue_enqueue(sq->sq_tq, &sq->sq_task);
}
@@ -498,6 +499,45 @@ mlx5e_xmit_locked(struct ifnet *ifp, str
return (err);
}
+static int
+mlx5e_xmit_locked_no_br(struct ifnet *ifp, struct mlx5e_sq *sq, struct mbuf
*mb)
+{
+ int err = 0;
+
+ if (unlikely((ifp->if_drv_flags & IFF_DRV_RUNNING) == 0 ||
+ sq->stopped != 0)) {
+ m_freem(mb);
+ return (ENETDOWN);
+ }
+
+ /* Do transmit */
+ if (mlx5e_sq_xmit(sq, &mb) != 0) {
+ /* NOTE: m_freem() is NULL safe */
+ m_freem(mb);
+ err = ENOBUFS;
+ }
+
+ /* Check if we need to write the doorbell */
+ if (likely(sq->doorbell.d64 != 0)) {
+ mlx5e_tx_notify_hw(sq, sq->doorbell.d32, 0);
+ sq->doorbell.d64 = 0;
+ }
+
+ /*
+ * 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);
+}
+
int
mlx5e_xmit(struct ifnet *ifp, struct mbuf *mb)
{
@@ -510,7 +550,13 @@ mlx5e_xmit(struct ifnet *ifp, struct mbu
m_freem(mb);
return (ENXIO);
}
- if (mtx_trylock(&sq->lock)) {
+
+ if (unlikely(sq->br == NULL)) {
+ /* rate limited traffic */
+ mtx_lock(&sq->lock);
+ ret = mlx5e_xmit_locked_no_br(ifp, sq, mb);
+ mtx_unlock(&sq->lock);
+ } else if (mtx_trylock(&sq->lock)) {
ret = mlx5e_xmit_locked(ifp, sq, mb);
mtx_unlock(&sq->lock);
} else {
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