menu_rebuild() uses lots of memory

my stats for D7 + all modules enables + devel (admin/build/modules) windows box (php 5.2.9-2 + apache 2.0.63)

eaccelerator enabled:
Memory used at: devel_boot()=0.27 MB, devel_shutdown()=6.67 MB, PHP peak usage=7.25 MB.

eaccelerator disabled:
Memory used at: devel_boot()=1.82 MB, devel_shutdown()=21.63 MB, PHP peak usage=22.25 MB.

with return; at menu_rebuild

eaccelerator enabled:
first run Memory used at: devel_boot()=1.64 MB, devel_shutdown()=18.57 MB, PHP peak usage=19.25 MB.
next run and others Memory used at: devel_boot()=0.26 MB, devel_shutdown()=2.86 MB, PHP peak usage=3.5 MB.

eaccelerator disabled:
Memory used at: devel_boot()=1.83 MB, devel_shutdown()=17.78 MB, PHP peak usage=18.25 MB.

As I see menu_rebuild() eats near 3-4M for own data

Here the screens of zend profiler (all core enabled + eaccelerator)

pm(*).png - normal d7 core

p(*).png - menu_rebuild() excluded

http://drupal.org/files/pm1.png
http://drupal.org/files/pm2.png
http://drupal.org/files/pm3.png

http://drupal.org/files/p1.png
http://drupal.org/files/p2.png
http://drupal.org/files/p3.png
http://drupal.org/files/p4.png

This with menu_rebuild() skip

Another series but without eaccelerator

The most expensive menu_rebuild() because _menu_navigation_links_rebuild()

This may be fixed by #550124: Remove prepared statement caching or #496500: Remove global placeholder counter.

We also changed menu_rebuild to do many smaller INSERT instead of one gigantic INSERT. Please reopen if there is a real outstanding issue.