Re: [Qemu-devel] [PATCH for-2.8 v1 00/60] Modular build of trace event files

[Lluís Vilanova]

Daniel P Berrange writes:

> On Thu, Sep 08, 2016 at 03:23:26PM +0200, Lluís Vilanova wrote:
>> Daniel P Berrange writes:
>> 
>> > I previously split the global trace-events file up into one file
>> > per-subdirectory to avoid merge conflict hell.
>> [...]
>> 
>> Sorry, I could not find the message where the infrastructure is modified to
>> provide this. But I think there's a more efficient way to provide modular
>> auto-generated tracing code without the hierarchical indexing you proposed.

> NB, the simpletrace backend requires a globally unique 32-bit integer ID
> to be assigned to each trace event, so even with the approach you suggest
> below we still need to be able to assign a global ID for each event.

> So while your suggest below avoids having to pass around the dstate
> arrays, which is nice, we still have to assign event id offsets to
> each trace-event file in some manner TBD.

Corect me if I'm wrong, but if we only require these consecutive IDs for
simpletrace, they don't need to be visible to the tracing headers (these IDs are
only used in "trace/generated-tracers.c"). Therefore, we can get them from the
trace-events-all file, and minimize the complexity of the changes to tracetool.


Cheers,
  Lluis