Qpid's move to CMake and effect on performance.

Qpid has now deprecated the automake build process and moved to CMake,
but I've got a nagging feeling.........

I've not *actually* got round to doing any benchmark/performance test
type things since I moved to using CMake myself and I'm wondering to
myself whether as part of Qpid/Proton release cycle anyone is has been
doing regression tests and in particular systematic performance tests?

One of my colleagues mentioned to me that he reckons that there was a
performance drop off between (I think) 0.12 and 0.18 but I've got no
evidence other than anecdotal from him and certainly no reproducer.

It did get me thinking about CMake though (though my colleague insists
he was using automake so there might still be an issue).

Am I correct in thinking that with CMake there are different "build
types" and that in "idiomatic" CMake usage it's "generally" via the use
of different build types that compiler optimisation flags get set?

In the automake build system I think that things were set to "-O3", but
I'm less convinced for CMake, indeed I *think* when at one point I made
Proton using make VERBOSE=1 I made a mental note that I didn't see any
optimisation flags.

The install instructions tend to say things along the lines of

mkdir build
cd build
cmake ..
make all
make install

CMAKE_BUILD_TYPE=Release
But I'm wondering if the third step really should be:
cmake CMAKE_BUILD_TYPE=Release ..

or somesuch.

I'm not much of a CMake expert (barely beyond a N00b) but if we do need
something like that to build with optimisation flags then I reckon we
*really* need to make sure that the Qpid and Proton build/install guides
get updated to reflect this otherwise users might be seeing
unrepresentative performance figures.

This might be second nature to CMake experts, but possibly/probably
isn't for everyone.

Thoughts?

Frase