From 7d58e6555870d01d85b181ba2a16b217a1ea8bdd Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Fri, 18 Sep 2020 18:00:46 +0200 Subject: net-sysfs: add backlog len and CPU id to softnet data 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 Signed-off-by: David S. Miller --- 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; } -- cgit v1.2.3-59-g8ed1b