[lttng-dev] Can't receive a lot of functions that i registerd as trace-points

Kienan Stewart kstewart at efficios.com
Tue Oct 24 15:59:45 EDT 2023

Hi Lin,

could you keep the lttng-dev list in CC on your replies in the future?

On 2023-10-24 09:25, Lin ArcX wrote:
> Thanks for your response. i fixed the names. here is new commands:
> # enable event for traced functions
> sudo lttng enable-event --kernel irq_handler_entry,napi_poll,net_dev_queue
> # different name with kernel
> sudo lttng enable-event --kernel 
> net_if_rx_entry,net_if_rx_ni_entry,net_napi_gro_receive_entry,net_if_receive_skb_list_entry,net_if_receive_skb
> Now In new tracefile i can see a lot of new events come. but still can't 
> see any trace from these:
> net_if_rx_ni_entry
> net_napi_gro_receive_entry
> net_if_receive_skb_list_entry
This looks fine to me.

On a linux 4.19 system, I ran a test with using lttng-modules 2.12.14. I 
saw events for "net_napi_gro_receive_entry".

In parallel with the LTTng tracing session, I ran

   perf stat -e 

The above allowed me to confirm that there were 
"net:napi_gro_receive_entry_events", but no "net:netif_rx_ni_entry" or 
"net:netif_receive_skb_list_entry" occurrences in my test.

Are you seeing a situation where another tool is recording occurrences 
of the events that you think aren't being seen during your tracing session?


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