2013/2/18 Kevin Wilson <wkevils@gmail.com>:

Hi, I added a network event trace thus:

echo 1 > /sys/kernel/debug/tracing/events/net/net_dev_xmit/enable

Afterwards I see many lines with net_dev_xmit in /sys/kernel/debug/tracing.

Now, looking in the source code, I see that there are two calls to trace_net_dev_xmit() in dev_hard_start_xmit(). These invocations are identical.

see: http://lxr.free-electrons.com/source/net/core/dev.c?v=2.6.37

Is there a way in which I can make the log say which of these invocations was called ? (without changing the dev_hard_start_xmit() method).

Yeah, you can enable the stacktraces in ftrace: echo stacktrace > /sys/kernel/debug/tracing/trace_options