On 18/09/2025 01:41, Jakub Kicinski wrote:
On Tue, 16 Sep 2025 19:12:54 +0000 Vadim Fedorenko wrote:
IEEE 802.3ck-2022 defines counters for FEC bins and 802.3df-2024
clarifies it a bit further. Implement reporting interface through as
addition to FEC stats available in ethtool.
diff --git a/Documentation/netlink/specs/ethtool.yaml
b/Documentation/netlink/specs/ethtool.yaml
index 7a7594713f1f..de5008266884 100644
--- a/Documentation/netlink/specs/ethtool.yaml
+++ b/Documentation/netlink/specs/ethtool.yaml
@@ -1219,6 +1219,23 @@ attribute-sets:
name: udp-ports
type: nest
nested-attributes: tunnel-udp
+ -
+ name: fec-hist
+ attr-cnt-name: __ethtool-a-fec-hist-cnt
s/__/--/
That will bring strong inconsistency in schema. All other attributes
have counter attribute with __ in the beginning:
name: fec-stat
attr-cnt-name: __ethtool-a-fec-stat-cnt
name: stats-grp
attr-cnt-name: __ethtool-a-stats-grp-cnt
name: stats
attr-cnt-name: __ethtool-a-stats-cnt
+ attributes:
+ -
+ name: bin-low
+ type: u32
+ -
+ name: bin-high
+ type: u32
We should add some doc: strings here so that the important info like
which one is inclusive is rendered right in the API reference
Yep, will add some doc
+ -
+ name: bin-val
+ type: uint
+ -
+ name: bin-val-per-lane
+ type: binary
probably good to doc this too
ack
+ sub-type: u64
-
name: fec-stat
attr-cnt-name: __ethtool-a-fec-stat-cnt
@@ -1242,6 +1259,11 @@ attribute-sets:
name: corr-bits
type: binary
sub-type: u64
+ -
+ name: hist
+ type: nest
+ multi-attr: True
+ nested-attributes: fec-hist
-
name: fec
attr-cnt-name: __ethtool-a-fec-cnt
diff --git a/Documentation/networking/ethtool-netlink.rst
b/Documentation/networking/ethtool-netlink.rst
index ab20c644af24..b270886c5f5d 100644
--- a/Documentation/networking/ethtool-netlink.rst
+++ b/Documentation/networking/ethtool-netlink.rst
@@ -1541,6 +1541,11 @@ Drivers fill in the statistics in the following
structure:
.. kernel-doc:: include/linux/ethtool.h
:identifiers: ethtool_fec_stats
+Statistics may have FEC bins histogram attribute ``ETHTOOL_A_FEC_STAT_HIST``
+as defined in IEEE 802.3ck-2022 and 802.3df-2024. Nested attributes will have
+the range of FEC errors in the bin (inclusive) and the amount of error events
+in the bin.
Does this sound better?
Optional ``ETHTOOL_A_FEC_STAT_HIST`` attributes form a FEC error
histogram, as defined in IEEE 802.3ck-2022 and 802.3df-2024
(histogram of number of errors within a single FEC block).
Each ``ETHTOOL_A_FEC_STAT_HIST`` entry contains error count
(optionally also broken down by SerDes lane) as well as metadata
about the bin. Bin range (low, high) is inclusive.
Ack
static void
-nsim_get_fec_stats(struct net_device *dev, struct ethtool_fec_stats *fec_stats)
+nsim_get_fec_stats(struct net_device *dev, struct ethtool_fec_stats *fec_stats,
+ struct ethtool_fec_hist *hist)
{
+ struct ethtool_fec_hist_value *values = hist->values;
+
+ hist->ranges = netdevsim_fec_ranges;
+
fec_stats->corrected_blocks.total = 123;
fec_stats->uncorrectable_blocks.total = 4;
+
+ values[0].bin_value = 445;
Bin 0 had per lane breakdown, can't core add up the lanes for the
driver?
Like it's done for blocks counter? Should we force drivers to keep 'sum'
value equal to ETHTOOL_STAT_NOT_SET when they provide per-lane values?
+ values[1].bin_value = 12;
+ values[2].bin_value = 2;
+ values[0].bin_value_per_lane[0] = 125;
+ values[0].bin_value_per_lane[1] = 120;
+ values[0].bin_value_per_lane[2] = 100;
+ values[0].bin_value_per_lane[3] = 100;
}
+/**
+ * struct ethtool_fec_hist_range - error bits range for FEC bins histogram
Don't say "FEC bin histogram" I think the word histogram implies that
the data is bin'ed up.
Ack
+ * statistics
+ * @low: low bound of the bin (inclusive)
+ * @high: high bound of the bin (inclusive)
+ */
@@ -113,7 +114,11 @@ static int fec_prepare_data(const struct ethnl_req_info
*req_base,
struct ethtool_fec_stats stats;
ethtool_stats_init((u64 *)&stats, sizeof(stats) / 8);
- dev->ethtool_ops->get_fec_stats(dev, &stats);
+ ethtool_stats_init((u64 *)data->fec_stat_hist.values,
+ ETHTOOL_FEC_HIST_MAX *
+ sizeof(struct ethtool_fec_hist_value) / 8);
sizeof(data->fec_stat_hist.values) / 8
would save you the multiplication?
yeah...
+ dev->ethtool_ops->get_fec_stats(dev, &stats,
+ &data->fec_stat_hist);
fec_stats_recalc(&data->corr, &stats.corrected_blocks);
fec_stats_recalc(&data->uncorr, &stats.uncorrectable_blocks);
+static int fec_put_hist(struct sk_buff *skb, const struct ethtool_fec_hist
*hist)
over 80 chars, please wrap (checkpatch --max-line-length=80)
ouch, that's proper strict check! :)
+{
+ const struct ethtool_fec_hist_range *ranges = hist->ranges;
+ const struct ethtool_fec_hist_value *values = hist->values;
+ struct nlattr *nest;
+ int i, j;
+
+ if (!ranges)
+ return 0;
+
+ for (i = 0; i < ETHTOOL_FEC_HIST_MAX; i++) {
+ if (i && !ranges[i].low && !ranges[i].high)
low and high should probably be unsigned now
ack
+ break;
+
+ if (WARN_ON_ONCE(values[i].bin_value == ETHTOOL_STAT_NOT_SET))
+ break;
+
+ nest = nla_nest_start(skb, ETHTOOL_A_FEC_STAT_HIST);
+ if (!nest)
+ return -EMSGSIZE;
+
+ if (nla_put_u32(skb, ETHTOOL_A_FEC_HIST_BIN_LOW,
+ ranges[i].low) ||
+ nla_put_u32(skb, ETHTOOL_A_FEC_HIST_BIN_HIGH,
+ ranges[i].high) ||
+ nla_put_uint(skb, ETHTOOL_A_FEC_HIST_BIN_VAL,
+ values[i].bin_value))
+ goto err_cancel_hist;
+ for (j = 0; j < ETHTOOL_MAX_LANES; j++) {
+ if (values[i].bin_value_per_lane[j] ==
ETHTOOL_STAT_NOT_SET)
You know, bin_value could be 'sum', and bin_value_per_lane could be
simply 'per_lane'.
SG, I'll change it
+ break;
+ }
{} brackets unnecessary
+ if (j && nla_put_64bit(skb, ETHTOOL_A_FEC_HIST_BIN_VAL_PER_LANE,
+ sizeof(u64) * j,
+ values[i].bin_value_per_lane,
+ ETHTOOL_A_FEC_STAT_PAD))
+ goto err_cancel_hist;
+
+ nla_nest_end(skb, nest);
+ }
+
+ return 0;
+
+err_cancel_hist:
+ nla_nest_cancel(skb, nest);
+ return -EMSGSIZE;
+}
We need a selftest. Add a case to stats.py and do basic sanity checking
on what the kernel spits out? Maybe 2 test cases - one for overall and
one for per-lane, cause mlx5 doesn't have per lane and we'd like the
test to pass there.
Yeah, sure, I'll add them as another patch to this series
