Yesterday a group of developers were sifting through crash reports that might be related to the new JIT code in Firefox 3.5. We found an unusual set of crashes with EXCEPTION_ILLEGAL_INSTRUCTION. After sifting through these crashes, I found that they have very similar patterns:

For a long while now (even before Google Chrome was announced), Mozilla has been examining ways to make Firefox better by splitting the work of displaying web pages up among multiple processes. There are several possible benefits of using multiple processes:

Things I’ve learned recently: