[PATCH FIX net v2] forcedeth: fix stats on hardware without extended stats support

From: David Decotigny
Date: Fri Nov 11 2011 - 21:28:25 EST


This change makes sure that tx_packets/rx_bytes ifconfig counters are
updated even on NICs that don't provide hardware support for these
stats: they are now updated in software. For the sake of consistency,
we also now have tx_bytes updated in software (hardware counters
include ethernet CRC, and software doesn't account for it).

This reverts parts of:
- "forcedeth: statistics optimization" (21828163b2)
- "forcedeth: Improve stats counters" (0bdfea8ba8)
- "forcedeth: remove unneeded stats updates" (4687f3f364)

Tested:
pktgen + loopback (http://patchwork.ozlabs.org/patch/124698/)
reports identical tx_packets/rx_packets and tx_bytes/rx_bytes.



Signed-off-by: David Decotigny <david.decotigny@xxxxxxxxxx>
---
drivers/net/ethernet/nvidia/forcedeth.c | 36 +++++++++++++++++++++++-------
1 files changed, 27 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/nvidia/forcedeth.c b/drivers/net/ethernet/nvidia/forcedeth.c
index 1dca570..1c61d36 100644
--- a/drivers/net/ethernet/nvidia/forcedeth.c
+++ b/drivers/net/ethernet/nvidia/forcedeth.c
@@ -609,7 +609,7 @@ struct nv_ethtool_str {
};

static const struct nv_ethtool_str nv_estats_str[] = {
- { "tx_bytes" },
+ { "tx_bytes" }, /* includes Ethernet FCS CRC */
{ "tx_zero_rexmt" },
{ "tx_one_rexmt" },
{ "tx_many_rexmt" },
@@ -637,7 +637,7 @@ static const struct nv_ethtool_str nv_estats_str[] = {
/* version 2 stats */
{ "tx_deferral" },
{ "tx_packets" },
- { "rx_bytes" },
+ { "rx_bytes" }, /* includes Ethernet FCS CRC */
{ "tx_pause" },
{ "rx_pause" },
{ "rx_drop_frame" },
@@ -649,7 +649,7 @@ static const struct nv_ethtool_str nv_estats_str[] = {
};

struct nv_ethtool_stats {
- u64 tx_bytes;
+ u64 tx_bytes; /* should be ifconfig->tx_bytes + 4*tx_packets */
u64 tx_zero_rexmt;
u64 tx_one_rexmt;
u64 tx_many_rexmt;
@@ -670,14 +670,14 @@ struct nv_ethtool_stats {
u64 rx_unicast;
u64 rx_multicast;
u64 rx_broadcast;
- u64 rx_packets;
+ u64 rx_packets; /* should be ifconfig->rx_packets */
u64 rx_errors_total;
u64 tx_errors_total;

/* version 2 stats */
u64 tx_deferral;
- u64 tx_packets;
- u64 rx_bytes;
+ u64 tx_packets; /* should be ifconfig->tx_packets */
+ u64 rx_bytes; /* should be ifconfig->rx_bytes + 4*rx_packets */
u64 tx_pause;
u64 rx_pause;
u64 rx_drop_frame;
@@ -1706,10 +1706,17 @@ static struct net_device_stats *nv_get_stats(struct net_device *dev)
if (np->driver_data & (DEV_HAS_STATISTICS_V1|DEV_HAS_STATISTICS_V2|DEV_HAS_STATISTICS_V3)) {
nv_get_hw_stats(dev);

+ /*
+ * Note: because HW stats are not always available and
+ * for consistency reasons, the following ifconfig
+ * stats are managed by software: rx_bytes, tx_bytes,
+ * rx_packets and tx_packets. The related hardware
+ * stats reported by ethtool should be equivalent to
+ * these ifconfig stats, with 4 additional bytes per
+ * packet (Ethernet FCS CRC).
+ */
+
/* copy to net_device stats */
- dev->stats.tx_packets = np->estats.tx_packets;
- dev->stats.rx_bytes = np->estats.rx_bytes;
- dev->stats.tx_bytes = np->estats.tx_bytes;
dev->stats.tx_fifo_errors = np->estats.tx_fifo_errors;
dev->stats.tx_carrier_errors = np->estats.tx_carrier_errors;
dev->stats.rx_crc_errors = np->estats.rx_crc_errors;
@@ -2380,6 +2387,9 @@ static int nv_tx_done(struct net_device *dev, int limit)
if (flags & NV_TX_ERROR) {
if ((flags & NV_TX_RETRYERROR) && !(flags & NV_TX_RETRYCOUNT_MASK))
nv_legacybackoff_reseed(dev);
+ } else {
+ dev->stats.tx_packets++;
+ dev->stats.tx_bytes += np->get_tx_ctx->skb->len;
}
dev_kfree_skb_any(np->get_tx_ctx->skb);
np->get_tx_ctx->skb = NULL;
@@ -2390,6 +2400,9 @@ static int nv_tx_done(struct net_device *dev, int limit)
if (flags & NV_TX2_ERROR) {
if ((flags & NV_TX2_RETRYERROR) && !(flags & NV_TX2_RETRYCOUNT_MASK))
nv_legacybackoff_reseed(dev);
+ } else {
+ dev->stats.tx_packets++;
+ dev->stats.tx_bytes += np->get_tx_ctx->skb->len;
}
dev_kfree_skb_any(np->get_tx_ctx->skb);
np->get_tx_ctx->skb = NULL;
@@ -2429,6 +2442,9 @@ static int nv_tx_done_optimized(struct net_device *dev, int limit)
else
nv_legacybackoff_reseed(dev);
}
+ } else {
+ dev->stats.tx_packets++;
+ dev->stats.tx_bytes += np->get_tx_ctx->skb->len;
}

dev_kfree_skb_any(np->get_tx_ctx->skb);
@@ -2678,6 +2694,7 @@ static int nv_rx_process(struct net_device *dev, int limit)
skb->protocol = eth_type_trans(skb, dev);
napi_gro_receive(&np->napi, skb);
dev->stats.rx_packets++;
+ dev->stats.rx_bytes += len;
next_pkt:
if (unlikely(np->get_rx.orig++ == np->last_rx.orig))
np->get_rx.orig = np->first_rx.orig;
@@ -2761,6 +2778,7 @@ static int nv_rx_process_optimized(struct net_device *dev, int limit)
}
napi_gro_receive(&np->napi, skb);
dev->stats.rx_packets++;
+ dev->stats.rx_bytes += len;
} else {
dev_kfree_skb(skb);
}
--
1.7.3.1

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