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Garbage collector tuning in Ruby 1.9

Asked 2011-02-13T16:25:11.303
19

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 (using perftools.rb) I notice that the GC stands for up to 30% of the total samples, and I'd like to see if it's possible to tune the GC to decrease this number. Are there any environment variables or other means by which you can set the number of heap slots, the malloc limit, etc. like you can with REE?

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11

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.

answered 2011-02-19T09:47:54.367

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