Note: The doc is updated with latest findings updated at the top

So sot seems to be the one that is invloved in the processing for the xml files; 
Tracing SotStorage; in sot/source/sdstor/storage.cxx 
So, SotStorage gets invoked once for the top directory, soffice.cfg/ and then UCBStorage_Impl::UCBStorage_Impl in sot/source/sdstor/ucbstorage.cxx gets called for every subdirectory recursively.

So, as noted below the xStorage does the complete xml file processing taking share/config/soffice.cfg/ as the toplevel directory and processes the xml files for everyfile available under soffice.cfg/ which includes the simpress/, global/ and the modules/ directories. So that gives some options as to whether to load all these at this point of execution or go further down and modify the processing. Did a couple of experiments with changed top-level directory name to soffice.cfg/global/ and also with completely skipping this altogether. To my surprise in both these cases, openoffice.org comes up without any issues  - much faster. Ofcourse, the first expecriment just reads the files that are under global/ only and the second experiment doesn't process any of those xml files; so has to be faster. One thing that I notice with these two experiments is that although OOo comes up fast, when you try to browse the menu bar it seems to be taking bit more time to get the menus rendered. Yet to confirm this though.
If so, we may have to look at the possibilities of loading these at a defered point of execution.    

Now, on to sfx2; SfxConfigManager seems to be the one that invoking all the xml process as part of createInstance...
Turns out that the xStorage thing --
 SotStorageRef xStorage( GetStorage( aCfgFileName, STREAM_STD_READ ) ); --
in sfx2\source\config\cfgmgr.cxx::SfxConfigManager() does all the xml storage stuff...

Though initially thought that the code in framework/ is the one handling these, the stuff in framework/  - like Moduleuiconfigurationmanager.cxx under source/configuration - comes in the path only after all the xml processing is done.

After the locale settings and creation of Resource manager, the createInstance invokes a series of library loads, speciafically libsfx and libfwe and like. The sfx and framework libraries.


cmduicollector.cxx - Seems to be handling all the xml files for menu, status toolbar and accelerator stuff.
Though, initially thought this could be the one processing, looks like it's some cmd line stuff.

Needs to explore these...
xml2cmp/source/xcd/filebuff.cxx::loadxmlfile()
xmlwrap.hxx::ScXMLImportWrapper

-----------------gdb-trace5-------------

(gdb) thread apply all bt
 
Thread 3 (Thread 1134947248 (LWP 15511)):
#0  0xffffe410 in ?? ()
#1  0x43a5dfc8 in ?? ()
#2  0x410aff0c in ?? () from /home/mnicel/m66-install-ooo-build/program/libuno_sal.so.3
#3  0x43a5dfb0 in ?? ()
#4  0x4152b138 in accept () from /lib/tls/libpthread.so.0
#5  0x40f177b3 in osl_acceptPipe () from /home/mnicel/m66-install-ooo-build/program/libuno_sal.so.3
#6  0x40e6ddfb in vos::OPipe::accept () from /home/mnicel/m66-install-ooo-build/program/libvos3gcc3.so
#7  0x08098ba4 in desktop::OfficeIPCThread::run (this=0x413e4170)
    at /home/mnicel/ooo-build/build/src680-m66/desktop/source/app/officeipcthread.cxx:535
#8  0x40e68842 in vos::_cpp_OThread_WorkerFunction () from /home/mnicel/m66-install-ooo-build/program/libvos3gcc3.so
#9  0x40e68829 in _OThread_WorkerFunction () from /home/mnicel/m66-install-ooo-build/program/libvos3gcc3.so
#10 0x40f0d900 in osl_getTextEncodingFromLocale () from /home/mnicel/m66-install-ooo-build/program/libuno_sal.so.3
#11 0x415269ed in start_thread () from /lib/tls/libpthread.so.0
#12 0x4178b9ca in clone () from /lib/tls/libc.so.6
 
Thread 2 (Thread 1132698544 (LWP 15510)):
#0  0xffffe410 in ?? ()
#1  0x43839978 in ?? ()
#2  0x00000000 in ?? ()
#3  0x00000000 in ?? ()
#4  0x4152891c in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib/tls/libpthread.so.0
#5  0x40f0a41e in osl_waitCondition () from /home/mnicel/m66-install-ooo-build/program/libuno_sal.so.3
#6  0x40e63701 in vos::OCondition::wait () from /home/mnicel/m66-install-ooo-build/program/libvos3gcc3.so
#7  0x40e6abee in vos::OTimerManager::run () from /home/mnicel/m66-install-ooo-build/program/libvos3gcc3.so
#8  0x40e68842 in vos::_cpp_OThread_WorkerFunction () from /home/mnicel/m66-install-ooo-build/program/libvos3gcc3.so
#9  0x40e68829 in _OThread_WorkerFunction () from /home/mnicel/m66-install-ooo-build/program/libvos3gcc3.so
#10 0x40f0d900 in osl_getTextEncodingFromLocale () from /home/mnicel/m66-install-ooo-build/program/libuno_sal.so.3
#11 0x415269ed in start_thread () from /lib/tls/libpthread.so.0
#12 0x4178b9ca in clone () from /lib/tls/libc.so.6
 
Thread 1 (Thread 1106182432 (LWP 15496)):
#0  0xffffe410 in ?? ()
#1  0xbfffdee8 in ?? ()
#2  0x00000013 in ?? ()
#3  0x4182e85b in UCBStorage_Impl::ReadContent (this=0x44dd10b0)
    at /home/mnicel/ooo-build/build/src680-m66/sot/source/sdstor/ucbstorage.cxx:2059
#4  0x4182dbe6 in UCBStorage_Impl::Init (this=0x44dd10b0)
    at /home/mnicel/ooo-build/build/src680-m66/sot/source/sdstor/ucbstorage.cxx:1952
#5  0x4182b0a8 in UCBStorage (this=0x44dcd310, rContent=@0xbfffe340, rName=@0x44dcd294, nMode=261, bDirect=0 '\0',
    bIsRoot=1 '\001') at /home/mnicel/ooo-build/build/src680-m66/sot/source/sdstor/ucbstorage.cxx:1739
#6  0x4184f6d7 in SotStorage (this=0x44dcd280, rContent=@0xbfffe340, rName=@0xbfffe3f0, nMode=261, nStorageMode=4)
    at /home/mnicel/ooo-build/build/src680-m66/sot/source/sdstor/storage.cxx:570
#7  0x442ff8b4 in GetStorage (rName=@0xbfffe3f0, nMode=261)
    at /home/mnicel/ooo-build/build/src680-m66/sfx2/source/config/cfgmgr.cxx:132
#8  0x44300a24 in SfxConfigManager (this=0x43d132a0, pStorage=0x0)
    at /home/mnicel/ooo-build/build/src680-m66/sfx2/source/config/cfgmgr.cxx:175
#9  0x440629cb in SfxApplication (this=0x43e27f70) at /home/mnicel/ooo-build/build/src680-m66/sfx2/source/appl/app.cxx:496
#10 0x44061e65 in SfxApplication::GetOrCreate () at /home/mnicel/ooo-build/build/src680-m66/sfx2/source/appl/app.cxx:403
#11 0x440263e1 in SfxGetpApp () at app.hxx:690
#12 0x4421ee4d in SfxGlobalEvents_Impl (this=0x43e22ba8, xSmgr=@0xbfffe6b0)
    at /home/mnicel/ooo-build/build/src680-m66/sfx2/source/notify/eventsupplier.cxx:609
#13 0x4421e720 in SfxGlobalEvents_Impl::impl_createInstance (xServiceManager=@0xbfffe6b0)
    at /home/mnicel/ooo-build/build/src680-m66/sfx2/source/notify/eventsupplier.cxx:598
#14 0x40ea05d3 in cppu::createStandardClassWithSequence ()
   from /home/mnicel/m66-install-ooo-build/program/libuno_cppuhelpergcc3.so.3
#15 0x40ea0876 in cppu::createStandardClassWithSequence ()
   from /home/mnicel/m66-install-ooo-build/program/libuno_cppuhelpergcc3.so.3
#16 0x40ea142e in cppu::createStandardClassWithSequence ()
   from /home/mnicel/m66-install-ooo-build/program/libuno_cppuhelpergcc3.so.3
#17 0x40ea215a in cppu::createStandardClassWithSequence ()
   from /home/mnicel/m66-install-ooo-build/program/libuno_cppuhelpergcc3.so.3
#18 0x40ea0876 in cppu::createStandardClassWithSequence ()
   from /home/mnicel/m66-install-ooo-build/program/libuno_cppuhelpergcc3.so.3
#19 0x40ea14d7 in cppu::createStandardClassWithSequence ()
   from /home/mnicel/m66-install-ooo-build/program/libuno_cppuhelpergcc3.so.3
#20 0x427d1d52 in stoc_smgr::OServiceManager::createInstanceWithContext ()
   from /home/mnicel/m66-install-ooo-build/program/servicemgr.uno.so
#21 0x427d24c5 in stoc_smgr::OServiceManager::createInstance ()
   from /home/mnicel/m66-install-ooo-build/program/servicemgr.uno.so
#22 0x0808c454 in desktop::Desktop::Main ()
#23 0x401d8e7c in SVMain () at /home/mnicel/ooo-build/build/src680-m66/vcl/source/app/svmain.cxx:263
#24 0x08086ac5 in sal_main (argc=1, argv=0xbfffefa4)
    at /home/mnicel/ooo-build/build/src680-m66/desktop/source/app/main.cxx:99
#25 0x08086a7c in main (argc=1, argv=0xbfffefa4) at /home/mnicel/ooo-build/build/src680-m66/desktop/source/app/main.cxx:94
(gdb)


-----------------gdb-trace5-------------


-----------------gdb-trace1-------------
(gdb) r
Starting program: /home/mnicel/m66-install-ooo-build/program/soffice.bin
[Thread debugging using libthread_db enabled]
[New Thread 1105258880 (LWP 616)]
[New Thread 1131555760 (LWP 636)]
[New Thread 1133804464 (LWP 637)]
Detaching after fork from child process 644.
aCfgFileName = file:///home/mnicel/m66-install-ooo-build/share/config/soffice.cfg
Program received signal SIGSTOP, Stopped (signal).
[Switching to Thread 1105258880 (LWP 616)]
0xffffe410 in ?? ()
(gdb) thread apply all bt
 
Thread 3 (Thread 1133804464 (LWP 637)):
#0  0xffffe410 in ?? ()
#1  0x43947028 in ?? ()
#2  0x40fecf0c in ?? () from ./libuno_sal.so.3
#3  0x43947010 in ?? ()
#4  0x41468138 in accept () from /lib/tls/libpthread.so.0
#5  0x40e547b3 in osl_acceptPipe () from ./libuno_sal.so.3
#6  0x40daadfb in vos::OPipe::accept () from ./libvos3gcc3.so
#7  0x08083649 in desktop::OfficeIPCThread::run ()
#8  0x40da5842 in vos::_cpp_OThread_WorkerFunction () from ./libvos3gcc3.so
#9  0x40da5829 in _OThread_WorkerFunction () from ./libvos3gcc3.so
#10 0x40e4a900 in osl_getTextEncodingFromLocale () from ./libuno_sal.so.3
#11 0x414639ed in start_thread () from /lib/tls/libpthread.so.0
#12 0x416c89ca in clone () from /lib/tls/libc.so.6
 
Thread 2 (Thread 1131555760 (LWP 636)):
#0  0xffffe410 in ?? ()
#1  0x43722978 in ?? ()
#2  0x00000000 in ?? ()
#3  0x00000000 in ?? ()
#4  0x4146591c in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib/tls/libpthread.so.0
#5  0x40e4741e in osl_waitCondition () from ./libuno_sal.so.3
#6  0x40da0701 in vos::OCondition::wait () from ./libvos3gcc3.so
#7  0x40da7bee in vos::OTimerManager::run () from ./libvos3gcc3.so
#8  0x40da5842 in vos::_cpp_OThread_WorkerFunction () from ./libvos3gcc3.so
#9  0x40da5829 in _OThread_WorkerFunction () from ./libvos3gcc3.so
#10 0x40e4a900 in osl_getTextEncodingFromLocale () from ./libuno_sal.so.3
#11 0x414639ed in start_thread () from /lib/tls/libpthread.so.0
#12 0x416c89ca in clone () from /lib/tls/libc.so.6

Thread 1 (Thread 1105258880 (LWP 616)):
#0  0xffffe410 in ?? ()
#1  0xbfffc398 in ?? ()
#2  0x00000013 in ?? ()
#3  0x00000268 in ?? ()
#4  0x41469201 in raise () from /lib/tls/libpthread.so.0
#5  0x441cd45f in SfxConfigManager::LoadConfiguration (this=0x43b043c8, rStorage=@0x44c59b58)
    at /home/mnicel/ooo-build/build/src680-m66/sfx2/source/config/cfgmgr.cxx:278
#6  0x441ccac3 in SfxConfigManager (this=0x43b043c8, pStorage=0x0)
    at /home/mnicel/ooo-build/build/src680-m66/sfx2/source/config/cfgmgr.cxx:180
---Type <return> to continue, or q <return> to quit---

#7  0x43f2ea0b in SfxApplication (this=0x43cf44a0) at /home/mnicel/ooo-build/build/src680-m66/sfx2/source/appl/app.cxx:496
#8  0x43f2dea5 in SfxApplication::GetOrCreate () at /home/mnicel/ooo-build/build/src680-m66/sfx2/source/appl/app.cxx:403
#9  0x43ef2421 in SfxGetpApp () at app.hxx:690
#10 0x440eae8d in SfxGlobalEvents_Impl (this=0x43cef098, xSmgr=@0xbfffc760)
    at /home/mnicel/ooo-build/build/src680-m66/sfx2/source/notify/eventsupplier.cxx:609
#11 0x440ea760 in SfxGlobalEvents_Impl::impl_createInstance (xServiceManager=@0xbfffc760)
    at /home/mnicel/ooo-build/build/src680-m66/sfx2/source/notify/eventsupplier.cxx:598
#12 0x40dde5d3 in cppu::createStandardClassWithSequence () from ./libuno_cppuhelpergcc3.so.3
#13 0x40dde876 in cppu::createStandardClassWithSequence () from ./libuno_cppuhelpergcc3.so.3
#14 0x40ddf42e in cppu::createStandardClassWithSequence () from ./libuno_cppuhelpergcc3.so.3
#15 0x40de015a in cppu::createStandardClassWithSequence () from ./libuno_cppuhelpergcc3.so.3
#16 0x40dde876 in cppu::createStandardClassWithSequence () from ./libuno_cppuhelpergcc3.so.3
#17 0x40ddf4d7 in cppu::createStandardClassWithSequence () from ./libuno_cppuhelpergcc3.so.3
#18 0x426bad52 in stoc_smgr::OServiceManager::createInstanceWithContext ()
   from /home/mnicel/m66-install-ooo-build/program/servicemgr.uno.so
#19 0x426bb4c5 in stoc_smgr::OServiceManager::createInstance ()
   from /home/mnicel/m66-install-ooo-build/program/servicemgr.uno.so
#20 0x08077ef4 in desktop::Desktop::Main ()
#21 0x4016fec0 in SVMain () from ./libvcl680li.so
#22 0x0807257d in sal_main ()
#23 0x0807252c in main ()

--------------gdb-trace1---------------------

--------------gdb-trace2---------------------

(gdb) thread apply all bt
 
Thread 3 (Thread 1134943152 (LWP 23770)):
#0  0xffffe410 in ?? ()
#1  0x43a5cfc8 in ?? ()
#2  0x410aff0c in ?? () from ./libuno_sal.so.3
#3  0x43a5cfb0 in ?? ()
#4  0x4152b138 in accept () from /lib/tls/libpthread.so.0
#5  0x40f177b3 in osl_acceptPipe () from ./libuno_sal.so.3
#6  0x40e6ddfb in vos::OPipe::accept () from ./libvos3gcc3.so
#7  0x0809ebf4 in desktop::OfficeIPCThread::run (this=0x413e3888)
    at /home/mnicel/ooo-build/build/src680-m66/desktop/source/app/officeipcthread.cxx:535
#8  0x40e68842 in vos::_cpp_OThread_WorkerFunction () from ./libvos3gcc3.so
#9  0x40e68829 in _OThread_WorkerFunction () from ./libvos3gcc3.so
#10 0x40f0d900 in osl_getTextEncodingFromLocale () from ./libuno_sal.so.3
#11 0x415269ed in start_thread () from /lib/tls/libpthread.so.0
#12 0x4178b9ca in clone () from /lib/tls/libc.so.6
 
Thread 2 (Thread 1132694448 (LWP 23769)):
#0  0xffffe410 in ?? ()
#1  0x43838978 in ?? ()
#2  0x00000000 in ?? ()
#3  0x00000000 in ?? ()
#4  0x4152891c in pthread_cond_timedwait@@GLIBC_2.3.2 () from /lib/tls/libpthread.so.0
#5  0x40f0a41e in osl_waitCondition () from ./libuno_sal.so.3
#6  0x40e63701 in vos::OCondition::wait () from ./libvos3gcc3.so
#7  0x40e6abee in vos::OTimerManager::run () from ./libvos3gcc3.so
#8  0x40e68842 in vos::_cpp_OThread_WorkerFunction () from ./libvos3gcc3.so
#9  0x40e68829 in _OThread_WorkerFunction () from ./libvos3gcc3.so
#10 0x40f0d900 in osl_getTextEncodingFromLocale () from ./libuno_sal.so.3
#11 0x415269ed in start_thread () from /lib/tls/libpthread.so.0
#12 0x4178b9ca in clone () from /lib/tls/libc.so.6

Thread 1 (Thread 1106180480 (LWP 23741)):
#0  0xffffe410 in ?? ()
#1  0xbfffc258 in ?? ()
#2  0x00000013 in ?? ()
#3  0x4430045f in SfxConfigManager::LoadConfiguration (this=0x43bd5360, rStorage=@0x44dccb30)
    at /home/mnicel/ooo-build/build/src680-m66/sfx2/source/config/cfgmgr.cxx:278
#4  0x442ffac3 in SfxConfigManager (this=0x43bd5360, pStorage=0x0)
    at /home/mnicel/ooo-build/build/src680-m66/sfx2/source/config/cfgmgr.cxx:180
#5  0x44061a0b in SfxApplication (this=0x43e274d0) at /home/mnicel/ooo-build/build/src680-m66/sfx2/source/appl/app.cxx:496
#6  0x44060ea5 in SfxApplication::GetOrCreate () at /home/mnicel/ooo-build/build/src680-m66/sfx2/source/appl/app.cxx:403
#7  0x44025421 in SfxGetpApp () at app.hxx:690
#8  0x4421de8d in SfxGlobalEvents_Impl (this=0x43e220c8, xSmgr=@0xbfffc620)
    at /home/mnicel/ooo-build/build/src680-m66/sfx2/source/notify/eventsupplier.cxx:609
#9  0x4421d760 in SfxGlobalEvents_Impl::impl_createInstance (xServiceManager=@0xbfffc620)
    at /home/mnicel/ooo-build/build/src680-m66/sfx2/source/notify/eventsupplier.cxx:598
#10 0x40ea15d3 in cppu::createStandardClassWithSequence () from ./libuno_cppuhelpergcc3.so.3
#11 0x40ea1876 in cppu::createStandardClassWithSequence () from ./libuno_cppuhelpergcc3.so.3
#12 0x40ea242e in cppu::createStandardClassWithSequence () from ./libuno_cppuhelpergcc3.so.3
#13 0x40ea315a in cppu::createStandardClassWithSequence () from ./libuno_cppuhelpergcc3.so.3
#14 0x40ea1876 in cppu::createStandardClassWithSequence () from ./libuno_cppuhelpergcc3.so.3
#15 0x40ea24d7 in cppu::createStandardClassWithSequence () from ./libuno_cppuhelpergcc3.so.3
#16 0x427d0d52 in stoc_smgr::OServiceManager::createInstanceWithContext ()
   from /home/mnicel/m66-install-ooo-build/program/servicemgr.uno.so
#17 0x427d14c5 in stoc_smgr::OServiceManager::createInstance ()
   from /home/mnicel/m66-install-ooo-build/program/servicemgr.uno.so
#18 0x0808ebe1 in desktop::Desktop::Main (this=0xbfffcf40)
    at /home/mnicel/ooo-build/build/src680-m66/desktop/source/app/app.cxx:1477
#19 0x401d8e7c in SVMain () at /home/mnicel/ooo-build/build/src680-m66/vcl/source/app/svmain.cxx:263
#20 0x08088fe5 in sal_main (argc=1, argv=0xbfffd044)
    at /home/mnicel/ooo-build/build/src680-m66/desktop/source/app/main.cxx:99
#21 0x08088f9c in main (argc=1, argv=0xbfffd044) at /home/mnicel/ooo-build/build/src680-m66/desktop/source/app/main.cxx:94

-------------------------gdb-trace2---------------------------


