See the current amount of free and used memory in the system:
free -m
What actual time we have (in the console):
time = Benchmark.measure do
app.get '/needed-page'
end
puts time
Play with GC options (REE):
RUBY_HEAP_MIN_SLOTS=600000
RUBY_GC_MALLOC_LIMIT=59000000
RUBY_HEAP_FREE_MIN=100000