Inspect directly into a RubyString and avoid StringBuilder/char[]. #4128
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Inspect perf comparison. Script: obj = top = Object.new
100.times do
obj2 = Object.new
obj.instance_variable_set :@obj, obj2
obj = obj2
end
loop do
t = Time.now
1000.times { top.inspect }
puts Time.now - t
endBefore: After: |
This should reduce the overhead of inspecting by avoiding the intermediate StringBuilder/char[] and subsequent conversion to byte[]. There are a few extra objects created along the way (java.lang.String.getBytes, RubyString for class name, etc) but overall memory use should reduce around 3x: a US-ASCII string would need 2x byte size in the StringBuilder, and the builder is still alive when we create the eventual byte[] for a total of 3x max memory use during inspect. Relates to jruby#4127, but does not constitute a fix for memory issues there.
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This should reduce the overhead of inspecting by avoiding the
intermediate StringBuilder/char[] and subsequent conversion to
byte[]. There are a few extra objects created along the way
(java.lang.String.getBytes, RubyString for class name, etc) but
overall memory use should reduce around 3x: a US-ASCII
string would need 2x byte size in the StringBuilder, and the
builder is still alive when we create the eventual byte[] for a
total of 3x max memory use during inspect.
Relates to #4127, but does not constitute a fix for memory issues
there.