[dpdk-dev] [PATCH 3/3] null: add xstats to provide the number of rx polls

[Paul Atkins]

When using the null driver and passing in packets via
the rx ring, it is useful to know that the driver has
polled the ring. Add a count of rx polls to the xstats
to provide this information.

Signed-off-by: Paul Atkins <patkins at brocade.com>
---
 drivers/net/null/rte_eth_null.c |   70 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)

diff --git a/drivers/net/null/rte_eth_null.c b/drivers/net/null/rte_eth_null.c
index 176f477..3feab44 100644
--- a/drivers/net/null/rte_eth_null.c
+++ b/drivers/net/null/rte_eth_null.c
@@ -65,6 +65,15 @@ static const char *valid_arguments[] = {

 struct pmd_internals;

+struct eth_null_xstats {
+       rte_atomic64_t rx_polls;
+       rte_atomic64_t tx_polls;
+};
+
+struct eth_null_hw_stats {
+       uint64_t rx_polls;
+};
+
 struct null_queue {
        struct pmd_internals *internals;

@@ -74,6 +83,7 @@ struct null_queue {
        rte_atomic64_t rx_pkts;
        rte_atomic64_t tx_pkts;
        rte_atomic64_t err_pkts;
+       struct eth_null_xstats xstats;
 };

 struct pmd_internals {
@@ -109,6 +119,19 @@ static struct rte_eth_link pmd_link = {
        .link_status = 0
 };

+/* store statistics names and its offset in stats structure */
+struct eth_null_xstats_name_off {
+       char name[RTE_ETH_XSTATS_NAME_SIZE];
+       unsigned offset;
+};
+
+static const struct eth_null_xstats_name_off eth_null_stats_strings[] = {
+       {"rx_polls", offsetof(struct eth_null_xstats, rx_polls)},
+};
+
+#define ETH_NULL_NB_XSTATS_PER_Q (sizeof(eth_null_stats_strings) /     \
+                                 sizeof(eth_null_stats_strings[0]))
+
 static uint16_t
 eth_null_rx(void *q, struct rte_mbuf **bufs, uint16_t nb_bufs)
 {
@@ -175,6 +198,7 @@ eth_null_copy_rx_from_ring(void *q, struct rte_mbuf **bufs, 
uint16_t nb_bufs)
        i = rte_ring_mc_dequeue_burst(h->internals->rx_ring, (void **)bufs,
                                      nb_bufs);
        rte_atomic64_add(&h->rx_pkts, 1);
+       rte_atomic64_add(&h->xstats.rx_polls, 1);

        return i;
 }
@@ -231,6 +255,7 @@ eth_null_copy_tx_to_ring(void *q, struct rte_mbuf **bufs, 
uint16_t nb_bufs)
                                   nb_bufs);

        rte_atomic64_add(&h->tx_pkts, 1);
+       rte_atomic64_add(&h->tx_pkts, i);

        return i;
 }
@@ -410,6 +435,49 @@ eth_stats_reset(struct rte_eth_dev *dev)
        }
 }

+static int
+eth_xstats_get(struct rte_eth_dev *dev, struct rte_eth_xstats *xstats,
+              unsigned n)
+{
+       struct pmd_internals *internal;
+       unsigned count = ETH_NULL_NB_XSTATS_PER_Q * dev->data->nb_rx_queues;
+       unsigned q, i = 0;
+       uint64_t val, *stats_ptr;
+
+       if (n < count)
+               return count;
+
+       internal = dev->data->dev_private;
+
+       /* Extended stats */
+       count = 0;
+       for (q = 0; q < ETH_NULL_NB_XSTATS_PER_Q; q++) {
+               for (i = 0; i < dev->data->nb_rx_queues; i++) {
+                       stats_ptr = RTE_PTR_ADD(
+                               &internal->rx_null_queues[q].xstats,
+                               eth_null_stats_strings[i].offset +
+                               q * sizeof(uint64_t));
+                       val = *stats_ptr;
+                       snprintf(xstats[count].name, sizeof(xstats[count].name),
+                                "rx_queue_%u_%s", q,
+                                eth_null_stats_strings[count].name);
+                       xstats[count++].value = val;
+               }
+       }
+       return count;
+}
+
+static void
+eth_xstats_reset(struct rte_eth_dev *dev)
+{
+       struct pmd_internals *internal;
+       unsigned i;
+
+       internal = dev->data->dev_private;
+       for (i = 0; i < dev->data->nb_rx_queues; i++)
+               internal->rx_null_queues[i].xstats.rx_polls.cnt = 0;
+}
+
 static void
 eth_queue_release(void *q)
 {
@@ -523,6 +591,8 @@ static const struct eth_dev_ops ops = {
        .link_update = eth_link_update,
        .stats_get = eth_stats_get,
        .stats_reset = eth_stats_reset,
+       .xstats_get = eth_xstats_get,
+       .xstats_reset = eth_xstats_reset,
        .reta_update = eth_rss_reta_update,
        .reta_query = eth_rss_reta_query,
        .rss_hash_update = eth_rss_hash_update,
-- 
1.7.10.4