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Re: [Qemu-devel] [PATCH for-2.8 v1 00/60] Modular build of trace event f
From: |
Lluís Vilanova |
Subject: |
Re: [Qemu-devel] [PATCH for-2.8 v1 00/60] Modular build of trace event files |
Date: |
Wed, 14 Sep 2016 15:26:06 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux) |
Daniel P Berrange writes:
> On Tue, Sep 13, 2016 at 08:36:25PM +0200, Lluís Vilanova wrote:
>> 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.
> The IDs need to be present in the generated tracers files which are split
> up.
I'm not sure if I'm just missing what you mean.
Changing any of the trace-events files will trigger a recompilation of the .c
files specific to the simpletrace backend, but won't trigger a recompile of all
QEMU files including any of the tracing headers (just the files including the
"trace.h" corresponding to the modified "trace-events").
Cheers,
Lluis
Re: [Qemu-devel] [PATCH for-2.8 v1 00/60] Modular build of trace event files, Daniel P. Berrange, 2016/09/13