Re: [Qemu-devel] [PATCH v2 00/47] Switch all subdirs over to modular trace.h file

["Daniel P. Berrange" <berrange@redhat.com>]

On Fri, Jan 06, 2017 at 03:54:56PM +0000, Daniel P. Berrange wrote:
> This is the final part of my trace events refactoring.
> 
> Previously we merged code that split trace-events up
> into one file per sub-directory. We also merged code
> to the code-generator that enables us to generate
> and use multiple independant sets of trace events.
> 
> This is the final glue that makes use of these two
> earlier changes, so that we actually generate a
> separate trace.h & trace.c file per sub-directory.
> 
> The result is that when adding a new trace event to
> a file, only files in that sub-directory get rebuilt.
> Theoretically the build is faster too, since each
> source file includes a much smaller trace.h that
> only contains probes relevant to it. In reality this
> speed benefit is probably marginal & lost in the noise.
> 
> The first patch introduces the new Makefile rules to
> handle modular building.
> 
> The next 43 patches convert over each sub-directory.
> They are totally boring and repetative. The only
> exception is the patch for target/s390x which hit
> a bit of makefile pain, explained in its commit msg.
> 
> The 45th patch removes the old, now unused, Makefile
> rules for non-modular trace building.
> 
> The 46th patch documents the new approach
> 
> The final patch is just a small tweak to error
> reporting, unrelated to the refactoring.

Oh I should say I tested this with

 ./configure --enable-trace-backends=log,simple,ust,nop,dtrace,ftrace,syslog

ie, all user + system emulators enabled and all trace backends
enabled.

Before rebasing to current git master I had also done the
same, testing against each patch in the series, so it should
be fully bisectable. It's also been through the standard travis
tests.

Regards,
Daniel
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