ping.
On 06.08.2015 17:32, Ilya Maximets wrote:
> Currently tx_qid is equal to pmd->core_id. This leads to unexpected
> behavior if pmd-cpu-mask different from '/(0*)(1|3|7)?(f*)/',
> e.g. if core_ids are not sequential, or doesn't start from 0, or both.
>
> Example:
> starting 2 pmd threads with 1 port, 2 rxqs per port,
> pmd-cpu-mask = 00000014 and let dev->real_n_txq = 2
>
> It that case pmd_1->tx_qid = 2, pmd_2->tx_qid = 4 and
> txq_needs_locking = true (if device hasn't ovs_numa_get_n_cores()+1
> queues).
>
> In that case, after truncating in netdev_dpdk_send__():
> 'qid = qid % dev->real_n_txq;'
> pmd_1: qid = 2 % 2 = 0
> pmd_2: qid = 4 % 2 = 0
>
> So, both threads will call dpdk_queue_pkts() with same qid = 0.
> This is unexpected behavior if there is 2 tx queues in device.
> Queue #1 will not be used and both threads will lock queue #0
> on each send.
>
> Fix that by introducing per pmd thread hash map 'tx_queues', where will
> be stored all available tx queues for that pmd thread with
> port_no as a key(hash). All tx_qid-s will be unique per port and
> sequential to prevent described unexpected mapping after truncating.
>
> Implemented infrastructure can be used in the future to choose
> between all tx queues available for that pmd thread.
>
> Signed-off-by: Ilya Maximets <i.maxim...@samsung.com>
> ---
> lib/dpif-netdev.c | 110
> ++++++++++++++++++++++++++++++++++++++++++++----------
> 1 file changed, 91 insertions(+), 19 deletions(-)
>
> diff --git a/lib/dpif-netdev.c b/lib/dpif-netdev.c
> index c144352..309994c 100644
> --- a/lib/dpif-netdev.c
> +++ b/lib/dpif-netdev.c
> @@ -365,6 +365,13 @@ struct dp_netdev_pmd_cycles {
> atomic_ullong n[PMD_N_CYCLES];
> };
>
> +struct dp_netdev_pmd_txq {
> + struct cmap_node node; /* In owning dp_netdev_pmd_thread's */
> + /* 'tx_queues'. */
> + struct dp_netdev_port *port;
> + int tx_qid;
> +};
> +
> /* PMD: Poll modes drivers. PMD accesses devices via polling to eliminate
> * the performance overhead of interrupt processing. Therefore netdev can
> * not implement rx-wait for these devices. dpif-netdev needs to poll
> @@ -420,8 +427,8 @@ struct dp_netdev_pmd_thread {
> /* threads on same numa node. */
> unsigned core_id; /* CPU core id of this pmd thread. */
> int numa_id; /* numa node id of this pmd thread. */
> - int tx_qid; /* Queue id used by this pmd thread to
> - * send packets on all netdevs */
> + struct cmap tx_queues; /* Queue ids used by this pmd thread to
> + * send packets to ports */
>
> /* Only a pmd thread can write on its own 'cycles' and 'stats'.
> * The main thread keeps 'stats_zero' and 'cycles_zero' as base
> @@ -2602,6 +2609,46 @@ dpif_netdev_wait(struct dpif *dpif)
> seq_wait(tnl_conf_seq, dp->last_tnl_conf_seq);
> }
>
> +static void
> +pmd_flush_tx_queues(struct dp_netdev_pmd_thread *pmd)
> +{
> + struct dp_netdev_pmd_txq *txq;
> +
> + CMAP_FOR_EACH (txq, node, &pmd->tx_queues) {
> + cmap_remove(&pmd->tx_queues, &txq->node,
> + hash_port_no(txq->port->port_no));
> + port_unref(txq->port);
> + free(txq);
> + }
> +}
> +
> +static void OVS_UNUSED
> +pmd_tx_queues_print(struct dp_netdev_pmd_thread *pmd)
> +{
> + struct dp_netdev_pmd_txq *txq;
> +
> + CMAP_FOR_EACH (txq, node, &pmd->tx_queues) {
> + VLOG_INFO("Core_id: %d, Port: %s, tx_qid: %d\n",
> + pmd->core_id, netdev_get_name(txq->port->netdev),
> + txq->tx_qid);
> + }
> +}
> +
> +static struct dp_netdev_pmd_txq *
> +pmd_lookup_txq(const struct dp_netdev_pmd_thread *pmd,
> + const struct dp_netdev_port *port)
> +{
> + struct dp_netdev_pmd_txq *txq;
> +
> + CMAP_FOR_EACH_WITH_HASH (txq, node, hash_port_no(port->port_no),
> + &pmd->tx_queues) {
> + if (txq->port == port) {
> + return txq;
> + }
> + }
> + return NULL;
> +}
> +
> struct rxq_poll {
> struct dp_netdev_port *port;
> struct netdev_rxq *rx;
> @@ -2613,16 +2660,20 @@ pmd_load_queues(struct dp_netdev_pmd_thread *pmd,
> {
> struct rxq_poll *poll_list = *ppoll_list;
> struct dp_netdev_port *port;
> - int n_pmds_on_numa, index, i;
> + struct dp_netdev_pmd_txq *txq;
> + int n_pmds_on_numa, rx_index, tx_index, i;
>
> /* Simple scheduler for netdev rx polling. */
> + pmd_flush_tx_queues(pmd);
> +
> for (i = 0; i < poll_cnt; i++) {
> port_unref(poll_list[i].port);
> }
>
> poll_cnt = 0;
> n_pmds_on_numa = get_n_pmd_threads_on_numa(pmd->dp, pmd->numa_id);
> - index = 0;
> + rx_index = 0;
> + tx_index = 0;
>
> CMAP_FOR_EACH (port, node, &pmd->dp->ports) {
> /* Calls port_try_ref() to prevent the main thread
> @@ -2633,7 +2684,7 @@ pmd_load_queues(struct dp_netdev_pmd_thread *pmd,
> int i;
>
> for (i = 0; i < netdev_n_rxq(port->netdev); i++) {
> - if ((index % n_pmds_on_numa) == pmd->index) {
> + if ((rx_index % n_pmds_on_numa) == pmd->index) {
> poll_list = xrealloc(poll_list,
> sizeof *poll_list * (poll_cnt + 1));
>
> @@ -2642,7 +2693,20 @@ pmd_load_queues(struct dp_netdev_pmd_thread *pmd,
> poll_list[poll_cnt].rx = port->rxq[i];
> poll_cnt++;
> }
> - index++;
> + rx_index++;
> + }
> +
> + /* Last queue reserved for non pmd threads */
> + for (i = 0; i < netdev_n_txq(port->netdev) - 1; i++) {
> + if ((tx_index % n_pmds_on_numa) == pmd->index) {
> + txq = xmalloc(sizeof *txq);
> + port_ref(port);
> + txq->port = port;
> + txq->tx_qid = i;
> + cmap_insert(&pmd->tx_queues, &txq->node,
> + hash_port_no(port->port_no));
> + }
> + tx_index++;
> }
> }
> /* Unrefs the port_try_ref(). */
> @@ -2712,6 +2776,8 @@ reload:
> goto reload;
> }
>
> + pmd_flush_tx_queues(pmd);
> +
> for (i = 0; i < poll_cnt; i++) {
> port_unref(poll_list[i].port);
> }
> @@ -2825,16 +2891,6 @@ dp_netdev_pmd_get_next(struct dp_netdev *dp, struct
> cmap_position *pos)
> return next;
> }
>
> -static int
> -core_id_to_qid(unsigned core_id)
> -{
> - if (core_id != NON_PMD_CORE_ID) {
> - return core_id;
> - } else {
> - return ovs_numa_get_n_cores();
> - }
> -}
> -
> /* Configures the 'pmd' based on the input argument. */
> static void
> dp_netdev_configure_pmd(struct dp_netdev_pmd_thread *pmd, struct dp_netdev
> *dp,
> @@ -2843,7 +2899,6 @@ dp_netdev_configure_pmd(struct dp_netdev_pmd_thread
> *pmd, struct dp_netdev *dp,
> pmd->dp = dp;
> pmd->index = index;
> pmd->core_id = core_id;
> - pmd->tx_qid = core_id_to_qid(core_id);
> pmd->numa_id = numa_id;
>
> ovs_refcount_init(&pmd->ref_cnt);
> @@ -2854,9 +2909,20 @@ dp_netdev_configure_pmd(struct dp_netdev_pmd_thread
> *pmd, struct dp_netdev *dp,
> ovs_mutex_init(&pmd->flow_mutex);
> dpcls_init(&pmd->cls);
> cmap_init(&pmd->flow_table);
> - /* init the 'flow_cache' since there is no
> + cmap_init(&pmd->tx_queues);
> + /* init the 'flow_cache' and 'tx_queues' since there is no
> * actual thread created for NON_PMD_CORE_ID. */
> if (core_id == NON_PMD_CORE_ID) {
> + struct dp_netdev_port *port;
> + CMAP_FOR_EACH (port, node, &pmd->dp->ports) {
> + if (port_try_ref(port)) {
> + struct dp_netdev_pmd_txq * txq = xmalloc(sizeof *txq);
> + txq->port = port;
> + txq->tx_qid = ovs_numa_get_n_cores();
> + cmap_insert(&pmd->tx_queues, &txq->node,
> + hash_port_no(port->port_no));
> + }
> + }
> emc_cache_init(&pmd->flow_cache);
> }
> cmap_insert(&dp->poll_threads, CONST_CAST(struct cmap_node *,
> &pmd->node),
> @@ -2869,6 +2935,7 @@ dp_netdev_destroy_pmd(struct dp_netdev_pmd_thread *pmd)
> dp_netdev_pmd_flow_flush(pmd);
> dpcls_destroy(&pmd->cls);
> cmap_destroy(&pmd->flow_table);
> + cmap_destroy(&pmd->tx_queues);
> ovs_mutex_destroy(&pmd->flow_mutex);
> latch_destroy(&pmd->exit_latch);
> xpthread_cond_destroy(&pmd->cond);
> @@ -2885,6 +2952,7 @@ dp_netdev_del_pmd(struct dp_netdev_pmd_thread *pmd)
> * no actual thread uninit it for NON_PMD_CORE_ID. */
> if (pmd->core_id == NON_PMD_CORE_ID) {
> emc_cache_uninit(&pmd->flow_cache);
> + pmd_flush_tx_queues(pmd);
> } else {
> latch_set(&pmd->exit_latch);
> dp_netdev_reload_pmd__(pmd);
> @@ -3480,13 +3548,17 @@ dp_execute_cb(void *aux_, struct dp_packet **packets,
> int cnt,
> struct dp_netdev *dp = pmd->dp;
> int type = nl_attr_type(a);
> struct dp_netdev_port *p;
> + struct dp_netdev_pmd_txq *txq;
> int i;
>
> switch ((enum ovs_action_attr)type) {
> case OVS_ACTION_ATTR_OUTPUT:
> p = dp_netdev_lookup_port(dp, u32_to_odp(nl_attr_get_u32(a)));
> if (OVS_LIKELY(p)) {
> - netdev_send(p->netdev, pmd->tx_qid, packets, cnt, may_steal);
> + txq = pmd_lookup_txq(pmd, p);
> + if (OVS_UNLIKELY(!txq))
> + break;
> + netdev_send(p->netdev, txq->tx_qid, packets, cnt, may_steal);
> return;
> }
> break;
>
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