Currently the backlog status in not exposed to user-space.
Since long backlogs (or simply not empty ones) can be a
source of noticeable latency, -RT deployments need some way
to inspect it.
Additionally, there isn't a direct match between 'softnet_stat'
lines and the related CPU - sd for offline CPUs are not dumped -
so this patch also includes the CPU id into such entry.
Signed-off-by: Paolo Abeni <pab...@redhat.com>
---
net/core/net-procfs.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/net/core/net-procfs.c b/net/core/net-procfs.c
index 6bbd06f7dc7d..c714e6a9dad4 100644
--- a/net/core/net-procfs.c
+++ b/net/core/net-procfs.c
@@ -116,6 +116,12 @@ static int dev_seq_show(struct seq_file *seq, void *v)
return 0;
}
+static u32 softnet_backlog_len(struct softnet_data *sd)
+{
+ return skb_queue_len_lockless(&sd->input_pkt_queue) +
+ skb_queue_len_lockless(&sd->process_queue);
+}
+
static struct softnet_data *softnet_get_online(loff_t *pos)
{
struct softnet_data *sd = NULL;
@@ -159,12 +165,17 @@ static int softnet_seq_show(struct seq_file *seq, void *v)
rcu_read_unlock();
#endif
+ /* the index is the CPU id owing this sd. Since offline CPUs are not
+ * displayed, it would be othrwise not trivial for the user-space
+ * mapping the data a specific CPU
+ */
seq_printf(seq,
- "%08x %08x %08x %08x %08x %08x %08x %08x %08x %08x %08x\n",
+ "%08x %08x %08x %08x %08x %08x %08x %08x %08x %08x %08x %08x
%08x\n",
sd->processed, sd->dropped, sd->time_squeeze, 0,
0, 0, 0, 0, /* was fastroute */
0, /* was cpu_collision */
- sd->received_rps, flow_limit_count);
+ sd->received_rps, flow_limit_count,
+ softnet_backlog_len(sd), (int)seq->index);
return 0;
}
--
2.26.2
