[ruby-core:27530] Re: better GC?

On Sat, Jan 09, 2010 at 03:13:22AM +0900, Brent Roman wrote:
> 
> Paul,
> 
> If compatibility with 'C' extensions is not a major concern for you, I'm
> curious to learn why you haven't  tried using JRUBY?  Or, have you?

For one application where we deployed both JRuby and Ruby 1.8, JRuby was
able to significantly outperform Ruby 1.8 in terms of total cpu
utilization and latency.  However, JRuby with the default GC settings
still periodically became unresponsive for about 1-2 seconds throughout
the running time of of the application.  Switching to an incremental GC
made these gaps disappear, but by that point it was just an experiment
for my own curiosity; the amount of effort to setup JRuby and tune the
GC exceeded the time allocated to the project.  In the end I went on a
2-month vacation, and when I came back, the entire application had been
rewritten in C++.

(in Ruby's defense here, the next 1-2 months of my time when I got back
were spent fixing the C++ code and adding missing features.  So the
perceived cost of C++ was lower, but in the end the actual cost ended up
being much higher than the team expected).

Paul