RE: ftrace trace_raw_pipe format

From: David Laight
Date: Wed Dec 18 2019 - 12:28:19 EST


From: Steven Rostedt
> Sent: 17 December 2019 22:34
>
> > I'm trying to 'grok' the trace_raw_pipe data that ftrace generates.
> > I've some 3rd party code that post-processes it, but doesn't like wrapped traces
> > because (I think) the traces from different cpus start at different times.
> >
> > I can't seem to find any documentation at all...
...
> You may want to use libtraceevent (which will, hopefully, soon
> be in debian!). Attached is a simple program that reads the data using
> it and prints out the format.

The problem is that I don't want to print the trace, I want to fix
some trace files so that another program doesn't barf at them.

I guess I can try to reverse engineer the library code.

It would also be nice if there was a way that some standard program
(like cat) could read out the trace files without blocking at the end
when the trace is inactive.

David

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