Slow `/namespace/project/blob/master/filename` endpoint on EE

Problem

Today, I was taking benchmark on http://local.gitlab.test:8181/root/test-proj/blob/master/README.md endpoint on my local machine, and surprisingly there is a significant difference between CE and EE.

In CE, the endpoint renders multiple partials. Here are the list of slow hamls and its timing.

app/views/projects/blob/show.html.haml : 500 msec
  app/views/projects/blob/_blob.html.haml : 324 msec

app/views/layouts/application.html.haml : 713 msec
  app/views/layouts/header/_default.html.haml : 273 msec
  app/views/layouts/_page.html.haml : 315 msec

In EE, the rendering takes 4-5 times more time.

app/views/projects/blob/show.html.haml : 1980 msec
  app/views/projects/blob/_blob.html.haml : 1350 msec

app/views/layouts/application.html.haml : 2940 msec
  app/views/layouts/header/_default.html.haml : 1000 msec
  app/views/layouts/_page.html.haml : 1500 msec

I know EE has some extra features to be rendered, however, taking 4-5 sec to render a blob page simply annoying. Also, this makes me worried that EE gets slower and slower as we introduce more features.

How can we make this faster?

Proposal

TBD