From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: [PATCH net-next] net_sched: sch_fq: avoid calling ktime_get_ns() if not needed Date: Mon, 19 Nov 2018 17:30:19 -0800 Message-ID: <20181120013019.236811-1-edumazet@google.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Cc: netdev , Eric Dumazet , Eric Dumazet To: "David S . Miller" Return-path: Received: from mail-pf1-f196.google.com ([209.85.210.196]:39304 "EHLO mail-pf1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726119AbeKTL4z (ORCPT ); Tue, 20 Nov 2018 06:56:55 -0500 Received: by mail-pf1-f196.google.com with SMTP id c72so154900pfc.6 for ; Mon, 19 Nov 2018 17:30:23 -0800 (PST) Sender: netdev-owner@vger.kernel.org List-ID: There are two cases were we can avoid calling ktime_get_ns() : 1) Queue is empty. 2) Internal queue is not empty. Signed-off-by: Eric Dumazet --- net/sched/sch_fq.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/net/sched/sch_fq.c b/net/sched/sch_fq.c index 1da8864502d448cfa93a9c02da504af61a1093e5..1a662f2bb7bb7bb5507107f61657d44fa28ca991 100644 --- a/net/sched/sch_fq.c +++ b/net/sched/sch_fq.c @@ -414,16 +414,21 @@ static void fq_check_throttled(struct fq_sched_data *q, u64 now) static struct sk_buff *fq_dequeue(struct Qdisc *sch) { struct fq_sched_data *q = qdisc_priv(sch); - u64 now = ktime_get_ns(); struct fq_flow_head *head; struct sk_buff *skb; struct fq_flow *f; unsigned long rate; u32 plen; + u64 now; + + if (!sch->q.qlen) + return NULL; skb = fq_dequeue_head(sch, &q->internal); if (skb) goto out; + + now = ktime_get_ns(); fq_check_throttled(q, now); begin: head = &q->new_flows; -- 2.19.1.1215.g8438c0b245-goog