From e543002f77f463501d47fab43acf7ba881e9dcaf Mon Sep 17 00:00:00 2001 From: Jesper Dangaard Brouer Date: Tue, 15 Aug 2017 21:11:03 +0200 Subject: qdisc: add tracepoint qdisc:qdisc_dequeue for dequeued SKBs The main purpose of this tracepoint is to monitor bulk dequeue in the network qdisc layer, as it cannot be deducted from the existing qdisc stats. The txq_state can be used for determining the reason for zero packet dequeues, see enum netdev_queue_state_t. Notice all packets doesn't necessary activate this tracepoint. As qdiscs with flag TCQ_F_CAN_BYPASS, can directly invoke sch_direct_xmit() when qdisc_qlen is zero. Remember that perf record supports filters like: perf record -e qdisc:qdisc_dequeue \ --filter 'ifindex == 4 && (packets > 1 || txq_state > 0)' Signed-off-by: Jesper Dangaard Brouer Signed-off-by: David S. Miller --- net/sched/sch_generic.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'net/sched/sch_generic.c') diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 57ba406f1437..c6b89a34e8d2 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -29,6 +29,7 @@ #include #include #include +#include /* Qdisc to use by default */ const struct Qdisc_ops *default_qdisc_ops = &pfifo_fast_ops; @@ -126,7 +127,7 @@ static struct sk_buff *dequeue_skb(struct Qdisc *q, bool *validate, q->q.qlen--; } else skb = NULL; - return skb; + goto trace; } *validate = true; skb = q->skb_bad_txq; @@ -139,7 +140,8 @@ static struct sk_buff *dequeue_skb(struct Qdisc *q, bool *validate, q->q.qlen--; goto bulk; } - return NULL; + skb = NULL; + goto trace; } if (!(q->flags & TCQ_F_ONETXQUEUE) || !netif_xmit_frozen_or_stopped(txq)) @@ -151,6 +153,8 @@ bulk: else try_bulk_dequeue_skb_slow(q, skb, packets); } +trace: + trace_qdisc_dequeue(q, txq, *packets, skb); return skb; } -- cgit v1.2.3