[dpdk-dev] [PATCH] ethdev: check number of queues less than RTE_ETHDEV_QUEUE_STAT_CNTRS

[Alejandro Lucero]

From: Bert van Leeuwen <bert.vanleeu...@netronome.com>

A device can have more than RTE_ETHDEV_QUEUE_STAT_CNTRS queues which
is used inside struct rte_eth_stats. Ideally, DPDK should be built with
RTE_ETHDEV_QUEUE_STAT_CNTRS to the maximum number of queues a device
can support, 65536, as uint16_t is used for keeping those values for
RX and TX. But of course, having such big arrays inside struct rte_eth_stats
is not a good idea.

Current default value is 16, which could likely be changed to 32 or 64
without too much opposition. And maybe it would be a good idea to modify
struct rte_eth_stats for allowing dynamically allocated arrays and maybe
some extra fields for keeping the array sizes.

Signed-off-by: Alejandro Lucero <alejandro.lucero at netronome.com>
---
 lib/librte_ether/rte_ethdev.c | 25 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/lib/librte_ether/rte_ethdev.c b/lib/librte_ether/rte_ethdev.c
index fde8112..4209ad0 100644
--- a/lib/librte_ether/rte_ethdev.c
+++ b/lib/librte_ether/rte_ethdev.c
@@ -1343,8 +1343,10 @@ get_xstats_count(uint8_t port_id)
        } else
                count = 0;
        count += RTE_NB_STATS;
-       count += dev->data->nb_rx_queues * RTE_NB_RXQ_STATS;
-       count += dev->data->nb_tx_queues * RTE_NB_TXQ_STATS;
+       count += RTE_MIN(dev->data->nb_rx_queues, RTE_ETHDEV_QUEUE_STAT_CNTRS) *
+                RTE_NB_RXQ_STATS;
+       count += RTE_MIN(dev->data->nb_tx_queues, RTE_ETHDEV_QUEUE_STAT_CNTRS) *
+                RTE_NB_TXQ_STATS;
        return count;
 }

@@ -1358,6 +1360,7 @@ rte_eth_xstats_get_names(uint8_t port_id,
        int cnt_expected_entries;
        int cnt_driver_entries;
        uint32_t idx, id_queue;
+       uint16_t num_q;

        cnt_expected_entries = get_xstats_count(port_id);
        if (xstats_names == NULL || cnt_expected_entries < 0 ||
@@ -1374,7 +1377,8 @@ rte_eth_xstats_get_names(uint8_t port_id,
                        "%s", rte_stats_strings[idx].name);
                cnt_used_entries++;
        }
-       for (id_queue = 0; id_queue < dev->data->nb_rx_queues; id_queue++) {
+       num_q = RTE_MIN(dev->data->nb_rx_queues, RTE_ETHDEV_QUEUE_STAT_CNTRS);
+       for (id_queue = 0; id_queue < num_q; id_queue++) {
                for (idx = 0; idx < RTE_NB_RXQ_STATS; idx++) {
                        snprintf(xstats_names[cnt_used_entries].name,
                                sizeof(xstats_names[0].name),
@@ -1384,7 +1388,8 @@ rte_eth_xstats_get_names(uint8_t port_id,
                }

        }
-       for (id_queue = 0; id_queue < dev->data->nb_tx_queues; id_queue++) {
+       num_q = RTE_MIN(dev->data->nb_tx_queues, RTE_ETHDEV_QUEUE_STAT_CNTRS);
+       for (id_queue = 0; id_queue < num_q; id_queue++) {
                for (idx = 0; idx < RTE_NB_TXQ_STATS; idx++) {
                        snprintf(xstats_names[cnt_used_entries].name,
                                sizeof(xstats_names[0].name),
@@ -1420,14 +1425,18 @@ rte_eth_xstats_get(uint8_t port_id, struct 
rte_eth_xstat *xstats,
        unsigned count = 0, i, q;
        signed xcount = 0;
        uint64_t val, *stats_ptr;
+       uint16_t nb_rxqs, nb_txqs;

        RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -EINVAL);

        dev = &rte_eth_devices[port_id];

+       nb_rxqs = RTE_MIN(dev->data->nb_rx_queues, RTE_ETHDEV_QUEUE_STAT_CNTRS);
+       nb_txqs = RTE_MIN(dev->data->nb_tx_queues, RTE_ETHDEV_QUEUE_STAT_CNTRS);
+
        /* Return generic statistics */
-       count = RTE_NB_STATS + (dev->data->nb_rx_queues * RTE_NB_RXQ_STATS) +
-               (dev->data->nb_tx_queues * RTE_NB_TXQ_STATS);
+       count = RTE_NB_STATS + (nb_rxqs * RTE_NB_RXQ_STATS) +
+               (nb_txqs * RTE_NB_TXQ_STATS);

        /* implemented by the driver */
        if (dev->dev_ops->xstats_get != NULL) {
@@ -1458,7 +1467,7 @@ rte_eth_xstats_get(uint8_t port_id, struct rte_eth_xstat 
*xstats,
        }

        /* per-rxq stats */
-       for (q = 0; q < dev->data->nb_rx_queues; q++) {
+       for (q = 0; q < nb_rxqs; q++) {
                for (i = 0; i < RTE_NB_RXQ_STATS; i++) {
                        stats_ptr = RTE_PTR_ADD(&eth_stats,
                                        rte_rxq_stats_strings[i].offset +
@@ -1469,7 +1478,7 @@ rte_eth_xstats_get(uint8_t port_id, struct rte_eth_xstat 
*xstats,
        }

        /* per-txq stats */
-       for (q = 0; q < dev->data->nb_tx_queues; q++) {
+       for (q = 0; q < nb_txqs; q++) {
                for (i = 0; i < RTE_NB_TXQ_STATS; i++) {
                        stats_ptr = RTE_PTR_ADD(&eth_stats,
                                        rte_txq_stats_strings[i].offset +
-- 
1.9.1