[PATCH 03/33] net/ena: update imissed stat with Rx overruns

[shaibran at amazon.com]

From: Shai Brandes <shaibran at amazon.com>

Depending on its acceleration support, the device updates
a different statistic when an ingress packet is dropped
because no buffers are available to hold it.
- In AWS instance types from later generations
'rx_overruns' is updated.
- Otherwise, in legacy instance types,
'rx_dropped_cnt' is updated.

That is, there is no need to report rx_overruns separately
as an xstat and the driver can simply sum up the two
self-contained counters as the 'imissed' statistic.

Signed-off-by: Shai Brandes <shaibran at amazon.com>
Reviewed-by: Amit Bernstein <amitbern at amazon.com>
---
 doc/guides/rel_notes/release_24_03.rst | 4 ++++
 drivers/net/ena/ena_ethdev.c           | 8 +++++---
 drivers/net/ena/ena_ethdev.h           | 1 -
 3 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/doc/guides/rel_notes/release_24_03.rst b/doc/guides/rel_notes/release_24_03.rst
index 879bb4944c..fb66d67d32 100644
--- a/doc/guides/rel_notes/release_24_03.rst
+++ b/doc/guides/rel_notes/release_24_03.rst
@@ -101,6 +101,10 @@ New Features
   * ``rte_flow_template_table_resize_complete()``.
     Complete table resize.
 
+* **Updated Amazon ena (Elastic Network Adapter) net driver.**
+
+  * Removed the reporting of `rx_overruns` errors from xstats and instead updated `imissed` stat with its value.
+
 * **Updated Atomic Rules' Arkville driver.**
 
   * Added support for Atomic Rules' TK242 packet-capture family of devices
diff --git a/drivers/net/ena/ena_ethdev.c b/drivers/net/ena/ena_ethdev.c
index b1e7de0541..d3f395a832 100644
--- a/drivers/net/ena/ena_ethdev.c
+++ b/drivers/net/ena/ena_ethdev.c
@@ -93,7 +93,6 @@ static const struct ena_stats ena_stats_global_strings[] = {
 	ENA_STAT_GLOBAL_ENTRY(dev_start),
 	ENA_STAT_GLOBAL_ENTRY(dev_stop),
 	ENA_STAT_GLOBAL_ENTRY(tx_drops),
-	ENA_STAT_GLOBAL_ENTRY(rx_overruns),
 };
 
 /*
@@ -4014,9 +4013,12 @@ static void ena_keep_alive(void *adapter_data,
 	tx_drops = ((uint64_t)desc->tx_drops_high << 32) | desc->tx_drops_low;
 	rx_overruns = ((uint64_t)desc->rx_overruns_high << 32) | desc->rx_overruns_low;
 
-	adapter->drv_stats->rx_drops = rx_drops;
+	/*
+	 * Depending on its acceleration support, the device updates a different statistic when
+	 * Rx packet is dropped because there are no available buffers to accommodate it.
+	 */
+	adapter->drv_stats->rx_drops = rx_drops + rx_overruns;
 	adapter->dev_stats.tx_drops = tx_drops;
-	adapter->dev_stats.rx_overruns = rx_overruns;
 }
 
 /**
diff --git a/drivers/net/ena/ena_ethdev.h b/drivers/net/ena/ena_ethdev.h
index 4988fbffb5..20b8307836 100644
--- a/drivers/net/ena/ena_ethdev.h
+++ b/drivers/net/ena/ena_ethdev.h
@@ -219,7 +219,6 @@ struct ena_stats_dev {
 	 * As a workaround it is being published as an extended statistic.
 	 */
 	u64 tx_drops;
-	u64 rx_overruns;
 };
 
 struct ena_stats_metrics {
-- 
2.17.1