Garbage collector tuning in Ruby 1.9

Question

I know about GC.enable/disable, but is there any way of controlling the Ruby 1.9 garbage collector in more detail?

When profiling my code

Answer 1

No.

There is no way to tune the 1.9.0–1.9.2 GC. However, you can compile a custom VM that exposes more or less the same tuning parameters as REE with this patch.

Answer 2

Yep, for short.

At first, basic constants, defining GC behavior (defaults value are shown) :

• RUBY_GC_MALLOC_LIMIT = 8000000 # - Initial size of a new memory slab, which is allocated after consuming all available memory
• RUBY_HEAP_MIN_SLOTS = 10000 #- Initial memory size, allocated at startup
• RUBY_HEAP_SLOTS_GROWTH_FACTOR = 1,8 #- New slab of memory is X times bigger than previous after each allocation.
• RUBY_HEAP_SLOTS_INCREMENT = 1 # Not sure, honestly :)

More details about GC, may help

A story from 37signals guys, which may definitively help you. They used manual GC calls (GC.start) on time, instead of memory size, and got huge boost.