From: "mame (Yusuke Endoh)" <mame@...>
Date: 2012-11-20T02:38:34+09:00
Subject: [ruby-core:49592] [ruby-trunk - Feature #5995] calling io_advise_internal() in read_all()


Issue #5995 has been updated by mame (Yusuke Endoh).

Target version set to next minor

Well, I wonder what I should do.
... I procrastinate the decision to next minor.

--
Yusuke Endoh <mame@tsg.ne.jp>
----------------------------------------
Feature #5995: calling io_advise_internal() in read_all()
https://bugs.ruby-lang.org/issues/5995#change-33106

Author: Glass_saga (Masaki Matsushita)
Status: Assigned
Priority: Normal
Assignee: mame (Yusuke Endoh)
Category: core
Target version: next minor


=begin
I propose to call io_advise_internal() in read_all().
It will increase performance.

I created a dummy file:
 dd if=/dev/zero of=dummy bs=1M count=100

Then, I ran the following:

 require 'benchmark'
 
 Benchmark.bm do |x|
   x.report do
     f = File.open("dummy") # dummy file(about 100MB )
     f.read
   end
 end

I freed page cache before each test:
 sudo sysctl -w vm.drop_caches=1

results on Ubuntu 11.10(3.0.0-15-server):

r34462:

 user     system      total        real
   0.050000   0.220000   0.270000 (  0.356033)
 
       user     system      total        real
   0.050000   0.190000   0.240000 (  0.332243)

       user     system      total        real
   0.060000   0.210000   0.270000 (  0.347758)

patched ruby:

 user     system      total        real
   0.030000   0.130000   0.160000 (  0.225866)

       user     system      total        real
   0.040000   0.170000   0.210000 (  0.250172)

       user     system      total        real
   0.040000   0.150000   0.190000 (  0.254654)

It shows the patch increases performance.
=end


-- 
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