Paper: Scalability by Design – Coding for Systems With Large CPU Counts via High Scalability – Building bigger, faster, more reliable websites.
by Todd Hoff on 1/26/09

The multi-cores are coming and software designed for fewer cores usually doesn’t work on more cores without substantial redesign. For a taste of the issues take a look at No new global mutexes! (and how to make the thread/connection pool work), which shows some of the difficulties of making MySQL perform on SMP servers.

In this paper, Richard Smith, a –Staff Engineer at Sun, goes into some nice detail on multi-core issues. His take home lessons are:

• Use fine-grained locking or lock-free strategy
• Document the strategy, including correctness criteria (invariants)
• Keep critical sections short
• Profile the code at both light and heavy load
• Collect HW performance counter data
• Identify bottleneck resource (there’s always at least one!)
• Eliminate or ameliorate it