Simple File IO is slower in JRuby 9.x than 1.7.x #4681
Description
When doing a simple benchmark for file IO (reading a big text file several times), I encountered a performance regression.
Used text file: test.txt
Benchmark code:
require 'benchmark'
Benchmark.bm do |x|
5.times do
x.report do
1000.times do
file = File.open('test.txt')
file.readlines
file.seek 0
end
end
end
end Environment
Running on Windows 10 (Version 1607).
Expected Behavior
I expected at least the same performance than JRuby 1.7.26.
Actual Behavior
JRuby 1.7.26:
C:\code> jruby -v .\io.rb
jruby 1.7.26 (1.9.3p551) 2016-08-26 69763b8 on Java HotSpot(TM) Client VM 1.8.0_111-b14 +jit [Windows 10-x86]
user system total real
1.466000 0.000000 1.466000 ( 1.466000)
1.332000 0.000000 1.332000 ( 1.331000)
0.887000 0.000000 0.887000 ( 0.887000)
1.108000 0.000000 1.108000 ( 1.108000)
1.301000 0.000000 1.301000 ( 1.301000)JRuby 9.1.10.0:
C:\code> jruby -v .\io.rb
jruby 9.1.10.0 (2.3.3) 2017-05-25 b09c48a Java HotSpot(TM) Client VM 25.111-b14 on 1.8.0_111-b14 +jit [mswin32-x86]
user system total real
19.523000 0.000000 19.523000 ( 19.522826)
21.285000 0.000000 21.285000 ( 21.284657)
20.799000 0.000000 20.799000 ( 20.799130)
19.675000 0.000000 19.675000 ( 19.675062)
19.823000 0.000000 19.823000 ( 19.823282)