Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753170Ab0GTEyP (ORCPT ); Tue, 20 Jul 2010 00:54:15 -0400 Received: from mail-ww0-f44.google.com ([74.125.82.44]:50033 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752761Ab0GTEyL (ORCPT ); Tue, 20 Jul 2010 00:54:11 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=subject:from:to:cc:in-reply-to:references:content-type:date :message-id:mime-version:x-mailer:content-transfer-encoding; b=cTj/1PC4gqW7IXcNUeydWJshBsqhqiflT360wdkvlGNETQoX8r0fL0KxGirvojP/BQ GLW20FRTjqWPJ5oe7fssj+fEQ/74sJEJyuzGN+/Ogmt1UdkSGBt+RfQySTH7dcecT5wy nIvCJ6Pf0ixWW9JDdJC/+DM42+InGIyQYImns= Subject: Re: [RFC PATCH v3 4/5] skb: add tracepoints to freeing skb From: Eric Dumazet To: Koki Sanagi Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, davem@davemloft.net, kaneshige.kenji@jp.fujitsu.com, izumi.taku@jp.fujitsu.com, kosaki.motohiro@jp.fujitsu.com, nhorman@tuxdriver.com, laijs@cn.fujitsu.com, scott.a.mcmillan@intel.com, rostedt@goodmis.org, fweisbec@gmail.com, mathieu.desnoyers@polymtl.ca In-Reply-To: <4C44F286.1050907@jp.fujitsu.com> References: <4C44F12F.5090908@jp.fujitsu.com> <4C44F286.1050907@jp.fujitsu.com> Content-Type: text/plain; charset="UTF-8" Date: Tue, 20 Jul 2010 06:54:03 +0200 Message-ID: <1279601643.2458.64.camel@edumazet-laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3880 Lines: 135 Le mardi 20 juillet 2010 à 09:49 +0900, Koki Sanagi a écrit : > [RFC PATCH v3 4/5] skb: add tracepoints to freeing skb > This patch adds tracepoint to consume_skb, dev_kfree_skb_irq and > skb_free_datagram_locked. Combinating with tracepoint on dev_hard_start_xmit, > we can check how long it takes to free transmited packets. And using it, we can > calculate how many packets driver had at that time. It is useful when a drop of > transmited packet is a problem. > > -0 [001] 241409.218333: consume_skb: skbaddr=dd6b2fb8 > -0 [001] 241409.490555: dev_kfree_skb_irq: skbaddr=f5e29840 > > udp-recv-302 [001] 515031.206008: skb_free_datagram_locked: skbaddr=f5b1d900 > > > Signed-off-by: Koki Sanagi > --- > include/trace/events/skb.h | 42 ++++++++++++++++++++++++++++++++++++++++++ > net/core/datagram.c | 1 + > net/core/dev.c | 2 ++ > net/core/skbuff.c | 1 + > 4 files changed, 46 insertions(+), 0 deletions(-) > > diff --git a/include/trace/events/skb.h b/include/trace/events/skb.h > index 4b2be6d..84c9041 100644 > --- a/include/trace/events/skb.h > +++ b/include/trace/events/skb.h > @@ -35,6 +35,48 @@ TRACE_EVENT(kfree_skb, > __entry->skbaddr, __entry->protocol, __entry->location) > ); > > +DECLARE_EVENT_CLASS(free_skb, > + > + TP_PROTO(struct sk_buff *skb), > + > + TP_ARGS(skb), > + > + TP_STRUCT__entry( > + __field( void *, skbaddr ) > + ), > + > + TP_fast_assign( > + __entry->skbaddr = skb; > + ), > + > + TP_printk("skbaddr=%p", __entry->skbaddr) > + > +); > + > +DEFINE_EVENT(free_skb, consume_skb, > + > + TP_PROTO(struct sk_buff *skb), > + > + TP_ARGS(skb) > + > +); > + > +DEFINE_EVENT(free_skb, dev_kfree_skb_irq, > + > + TP_PROTO(struct sk_buff *skb), > + > + TP_ARGS(skb) > + > +); > + > +DEFINE_EVENT(free_skb, skb_free_datagram_locked, > + > + TP_PROTO(struct sk_buff *skb), > + > + TP_ARGS(skb) > + > +); > + > TRACE_EVENT(skb_copy_datagram_iovec, > > TP_PROTO(const struct sk_buff *skb, int len), > diff --git a/net/core/datagram.c b/net/core/datagram.c > index f5b6f43..1ea32a0 100644 > --- a/net/core/datagram.c > +++ b/net/core/datagram.c > @@ -231,6 +231,7 @@ void skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb) > { > bool slow; > > + trace_skb_free_datagram_locked(skb); Here you unconditionally trace before the test on skb->users > if (likely(atomic_read(&skb->users) == 1)) > smp_rmb(); > else if (likely(!atomic_dec_and_test(&skb->users))) > diff --git a/net/core/dev.c b/net/core/dev.c > index 4acfec6..d979847 100644 > --- a/net/core/dev.c > +++ b/net/core/dev.c > @@ -131,6 +131,7 @@ > #include > #include > #include > +#include > #include > > #include "net-sysfs.h" > @@ -1581,6 +1582,7 @@ void dev_kfree_skb_irq(struct sk_buff *skb) > struct softnet_data *sd; > unsigned long flags; > > + trace_dev_kfree_skb_irq(skb); > local_irq_save(flags); > sd = &__get_cpu_var(softnet_data); > skb->next = sd->completion_queue; > diff --git a/net/core/skbuff.c b/net/core/skbuff.c > index 34432b4..a7b4036 100644 > --- a/net/core/skbuff.c > +++ b/net/core/skbuff.c > @@ -466,6 +466,7 @@ void consume_skb(struct sk_buff *skb) > smp_rmb(); > else if (likely(!atomic_dec_and_test(&skb->users))) > return; While here you trace _after_ the test on skb->users - and a "return;" , so you miss some consume_skb() calls > + trace_consume_skb(skb); > __kfree_skb(skb); > } > EXPORT_SYMBOL(consume_skb); > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/