Presentation from Stanford Drupal Camp, May 5th, 2012.
Much of Drupal high performance work focuses on sites like examiner.com that must scale massively to accommodate millions of users, and pursues the "hits-per-second" metric.
However, many Drupal site admins have smaller, low-traffic sites that run on shared hosting, and don't warrant the overhead of a dedicated server, Varnish, Acquia, or Pantheon. These sites run slowly for various reasons, and "seconds-per-hit" is a more meaningful metric.
I start with a high-level overview of how to assess and prioritize your performance problems, where they're coming from, and why they may (or may not) matter.
I also walk through debugging a poorly-performing site from the front end to the back end, and discuss performance improvements such as:
Drupal core performance settings
CSS and JS aggregation
Views and Panels caching
Boost
Authcache
I also cover testing and profiling tools such as devel, ApacheBench, and YSlow, and the built-in tools in browsers like Safari and Chrome.