I'm helping a friend to improve performance on their pretty mid-small sized magento store.

First thing I was looking is the Magento Profiler, from what I can see there is those methods that takes lots of time(6-7 seconds!)

    layout/db_update: cms_menu	6.5310	1	0	0
    layout/db_update: cms_page	6.5292	1	0	0
    layout/db_update: STORE_default	6.5274	1	0	0
    layout/db_update: THEME_frontend_agent_default	6.5256	1	0	0
    layout/db_update: cms_index_index	6.5236	1	0	0
    layout/db_update:	6.5217	1	0	0
    layout/db_update: customer_logged_out

Any ideas how to go deeper and understand whats the bottleneck? I guess its some slow mysql queries.

I'm looking for tools/tips to help me to dig into it and get extra info

thanks