How to analyze Rails's page performance

in my rails app on product for one of our pages I see this:

Started GET "/bobbb1" for 127.0.0.1 at 2011-09-27 13:31:47 -0700
  Processing by PagessController#show as HTML
....lots of queries

Rendered modules/_edit.html.erb (5.6ms)
Rendered modules/_show.html.erb (9.6ms)
Rendered feeds/_feed_items_tmpl.html.erb (2.3ms)
Rendered members/_edit.html.erb (1.1ms)
Rendered layouts/_header.html.erb (64.4ms)
Rendered layouts/_footer.html.erb (0.1ms)
Rendered pages/show.html.erb within layouts/application (105.1ms)
Completed 200 OK in 230ms (Views: 100.6ms | ActiveRecord: 11.4ms)

Why does rails show:

Completed 200 OK in 230ms

Yes then show: (Views: 100.6ms | ActiveRecord: 11.4ms)

This doesn't add up? What's the lag here. 开发者_C百科How can I diagnose where the performance bottlenecks are?

Thanks

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Rails includes built-in options for detailed profiling and benchmarking beyond basic logging. Some metrics are not available in all Ruby stacks (I understand 1.9.x includes more options.)

See http://guides.rubyonrails.org/v3.2.13/performance_testing.html