Currently when loading a session for the first time MidiPatchManager::instance
creates the MidiPatchManager singleton which calls MPM::refresh and all the
midnam files are parsed etc. MPM::set_session is then immediately called and
all the MPM state that has just been set when parsing all the midnam files is
cleared and the parsing of all the files is performed again but this time with
any session specific midnam patch files.
MPM::instance and MPM::set_session consume about 55% of the time spent in the
Session ctor according to kcachegrind and removing the double call to refresh
brings Session construction time for a particular test session down from 7.5s
to 5.5s
Tim Mayberry
9fd75e33fe