Messages in this thread | | | Date | Wed, 21 Jul 2010 16:02:57 +0900 | From | Koki Sanagi <> | Subject | Re: [RFC PATCH v3 4/5] skb: add tracepoints to freeing skb |
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(2010/07/20 20:50), Neil Horman wrote: > On Tue, Jul 20, 2010 at 09:49:10AM +0900, Koki Sanagi wrote: >> [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. >> >> <idle>-0 [001] 241409.218333: consume_skb: skbaddr=dd6b2fb8 >> <idle>-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 <sanagi.koki@jp.fujitsu.com> >> --- >> 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) >> + >> +); >> + > > Why create these last two tracepoints at all? dev_kfree_skb_irq will eventually > pass through kfree_skb anyway, getting picked up by the tracepoint there, the > while the latter won't (since it uses __kfree_skb instead), I think that could > be fixed up by add a call to trace_kfree_skb there directly, saving you two > tracepoints. > > Neil > I think dev_kfree_skb_irq isn't chased by trace_kfree_skb or trace_consume_skb completely. Because net_tx_action frees skb by __kfree_skb. So it is better to add trace_kfree_skb before it. skb_free_datagram_locked is same.
Thanks, Koki Sanagi. >> > >
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