net/sfc: fix Rx packets counter reported by basic stats
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Commit Message
Errors, missed and pauses should not be included in delivered
good Rx packets reported by ipackets.
Fixes: 1caab2f1e684 ("net/sfc: add basic statistics")
Cc: stable@dpdk.org
Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>
---
drivers/net/sfc/sfc.h | 2 ++
drivers/net/sfc/sfc_ethdev.c | 31 ++++++++++++++++++++++++++++++-
drivers/net/sfc/sfc_port.c | 14 ++++++++++++++
3 files changed, 46 insertions(+), 1 deletion(-)
Comments
On 1/17/2019 6:17 AM, Andrew Rybchenko wrote:
> Errors, missed and pauses should not be included in delivered
> good Rx packets reported by ipackets.
>
> Fixes: 1caab2f1e684 ("net/sfc: add basic statistics")
> Cc: stable@dpdk.org
>
> Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>
Applied to dpdk-next-net/master, thanks.
@@ -149,6 +149,8 @@ struct sfc_port {
uint64_t mac_stats_last_request_timestamp;
uint32_t mac_stats_mask[EFX_MAC_STATS_MASK_NPAGES];
+
+ uint64_t ipackets;
};
struct sfc_rss_hf_rte_to_efx {
@@ -503,6 +503,29 @@ sfc_tx_queue_release(void *queue)
sfc_adapter_unlock(sa);
}
+/*
+ * Some statistics are computed as A - B where A and B each increase
+ * monotonically with some hardware counter(s) and the counters are read
+ * asynchronously.
+ *
+ * If packet X is counted in A, but not counted in B yet, computed value is
+ * greater than real.
+ *
+ * If packet X is not counted in A at the moment of reading the counter,
+ * but counted in B at the moment of reading the counter, computed value
+ * is less than real.
+ *
+ * However, counter which grows backward is worse evil than slightly wrong
+ * value. So, let's try to guarantee that it never happens except may be
+ * the case when the MAC stats are zeroed as a result of a NIC reset.
+ */
+static void
+sfc_update_diff_stat(uint64_t *stat, uint64_t newval)
+{
+ if ((int64_t)(newval - *stat) > 0 || newval == 0)
+ *stat = newval;
+}
+
static int
sfc_stats_get(struct rte_eth_dev *dev, struct rte_eth_stats *stats)
{
@@ -540,7 +563,6 @@ sfc_stats_get(struct rte_eth_dev *dev, struct rte_eth_stats *stats)
stats->imissed = mac_stats[EFX_MAC_VADAPTER_RX_BAD_PACKETS];
stats->oerrors = mac_stats[EFX_MAC_VADAPTER_TX_BAD_PACKETS];
} else {
- stats->ipackets = mac_stats[EFX_MAC_RX_PKTS];
stats->opackets = mac_stats[EFX_MAC_TX_PKTS];
stats->ibytes = mac_stats[EFX_MAC_RX_OCTETS];
stats->obytes = mac_stats[EFX_MAC_TX_OCTETS];
@@ -566,6 +588,13 @@ sfc_stats_get(struct rte_eth_dev *dev, struct rte_eth_stats *stats)
mac_stats[EFX_MAC_RX_ALIGN_ERRORS] +
mac_stats[EFX_MAC_RX_JABBER_PKTS];
/* no oerrors counters supported on EF10 */
+
+ /* Exclude missed, errors and pauses from Rx packets */
+ sfc_update_diff_stat(&port->ipackets,
+ mac_stats[EFX_MAC_RX_PKTS] -
+ mac_stats[EFX_MAC_RX_PAUSE_PKTS] -
+ stats->imissed - stats->ierrors);
+ stats->ipackets = port->ipackets;
}
unlock:
@@ -87,6 +87,18 @@ sfc_port_update_mac_stats(struct sfc_adapter *sa)
return 0;
}
+static void
+sfc_port_reset_sw_stats(struct sfc_adapter *sa)
+{
+ struct sfc_port *port = &sa->port;
+
+ /*
+ * Reset diff stats explicitly since check which does not allow
+ * the statistics to grow backward could deny it.
+ */
+ port->ipackets = 0;
+}
+
int
sfc_port_reset_mac_stats(struct sfc_adapter *sa)
{
@@ -95,6 +107,8 @@ sfc_port_reset_mac_stats(struct sfc_adapter *sa)
rte_spinlock_lock(&port->mac_stats_lock);
rc = efx_mac_stats_clear(sa->nic);
+ if (rc == 0)
+ sfc_port_reset_sw_stats(sa);
rte_spinlock_unlock(&port->mac_stats_lock);
return rc;