Proving to myself that it really is faster to avoid using send...

results.txt

# 1.9.2

Rehearsal -------------------------------------------------------
no-send               1.950000   0.000000   1.950000 (  1.961587)
symbol-send           2.190000   0.000000   2.190000 (  2.192600)
string-send           4.790000   0.000000   4.790000 (  4.812341)
---------------------------------------------- total: 8.930000sec

                          user     system      total        real
no-send               2.330000   0.000000   2.330000 (  2.332294)
symbol-send           3.510000   0.010000   3.520000 (  3.529359)
string-send           8.030000   0.000000   8.030000 (  8.076293)

# 1.8.7

Rehearsal -------------------------------------------------------
no-send               2.800000   0.000000   2.800000 (  2.812871)
symbol-send           3.550000   0.000000   3.550000 (  3.561249)
string-send           6.210000   0.000000   6.210000 (  6.234676)
--------------------------------------------- total: 12.560000sec

                          user     system      total        real
no-send               4.700000   0.000000   4.700000 (  4.726431)
symbol-send           5.790000   0.000000   5.790000 (  5.813629)
string-send           7.460000   0.000000   7.460000 (  7.495963)

send_strategies_benchmark.rb

require 'benchmark'

def foo
  "bar"
end

n = 10_000_000

Benchmark.bmbm(20) do |b|
  b.report('no-send') do
    n.times { foo }
  end

  b.report('symbol-send') do
    n.times { send(:foo) }
  end

  b.report('string-send') do
    n.times { send('foo') }
  end
end