rails startup is ~5-10 times slower than MRI

Lots of good info in Charles's blog post:

http://blog.headius.com/2010/03/jruby-startup-time-tips.html

Here are my timings:

$ jruby -v
jruby 1.4.0 (ruby 1.8.7 patchlevel 174) (2009-11-04 6586) (Java HotSpot(TM) 64-Bit Server VM 1.6.0_15) [x86_64-java]

$ jruby -J-d32 -v
jruby 1.4.0 (ruby 1.8.7 patchlevel 174) (2009-11-04 6586) (Java HotSpot(TM) Client VM 1.6.0_17) [i386-java]

$ time jruby -S rake environment > /dev/null

real 0m14.367s
user 0m19.897s
sys 0m0.998s

$ time jruby -J-d32 -S rake environment > /dev/null

real 0m7.791s
user 0m8.599s
sys 0m0.513s

All variants involving nailgun (--ng-server with and without -J-d32, --ng with and without -J-d32) were slower than that.

We have made some great progress on this front. As it stands, on my MBP, I get:

$ time ruby -v -S rake environment
ruby 1.8.7 (2009-06-12 patchlevel 174) [universal-darwin10.0]
(in /Users/asari/Development/projects/barebones)

real	0m3.510s
user	0m0.830s
sys	0m0.444s

For JRuby trunk (not super, but not 5~10 times as originally reported):

$ jruby -b --version -S rake environment
jruby 1.6.0.dev (ruby 1.8.7 patchlevel 249) (2010-07-04 105217d) (Java HotSpot(TM) 64-Bit Server VM 1.6.0_20) [x86_64-java]
(in /Users/asari/Development/projects/barebones)
Runtime: 8104 ms

With nailgun, this eventually optimizes to about 5 seconds (first run took 12 seconds, but subsequent runs are much better):

$ jruby -b --ng --version -S rake environment
jruby 1.6.0.dev (ruby 1.8.7 patchlevel 249) (2010-07-04 105217d) (Java HotSpot(TM) 64-Bit Server VM 1.6.0_20) [x86_64-java]
(in /Users/asari/Development/projects/barebones)
Runtime: 4644 ms

I vote for resolving this ticket as 'fixed'.

Rails startup time still a major impediment for me and I consider it far from fixed.

'rake environment' in my real-world Rails app takes 15 seconds with 1.5.1.

Hi, John,

A couple of questions.

1. How long does it take for MRI to load your app?
2. Does -J-Djruby.debug.loadService.timing=true give you clues as to which library JRuby is taking long to load?

It doesn't run on MRI (requires JDBC) so I can't do direct comparisons unfortunately.

Upgrading to bundler --pre saved a few seconds.

Here's the current loadServiceTiming output. (This is a cool flag, thanks for sharing.) Nothing too surprising jumps out. Loading Rubygems, OpenSSL, and various parts of rails each take on the order of a half second. Mainly there's just a lot of dependencies that add up.

Another tip which may or may not make a difference is the more gems you have installed, the longer it takes to load a gem (in both JRuby and MRI).

1.6.0rc1 is slower than 1.5.6.

1.5.6:
real 0m12.517s
user 0m14.378s
sys 0m1.149s

1.6.0rc1:
real 0m13.368s
user 0m15.468s
sys 0m1.332s

On my machine, using the same Rails 3 app, I get the opposite result.

$ jruby -v; echo "exit" | time jruby script/rails console
jruby 1.5.6 (ruby 1.8.7 patchlevel 249) (2010-12-03 9cf97c3) (Java HotSpot(TM) 64-Bit Server VM 1.6.0_22) [x86_64-java]
Loading development environment (Rails 3.0.3)
jruby-1.5.6 :001 > exit
       11.93 real        16.54 user         0.96 sys

$ jruby -v; echo "exit" | time jruby script/rails console
jruby 1.6.0.RC1 (ruby 1.8.7 patchlevel 330) (2011-01-11 8626dc2) (Java HotSpot(TM) 64-Bit Server VM 1.6.0_22) [darwin-x86_64-java]
/Users/asari/Development/src/jruby/lib/ruby/gems/1.8/gems/bundler-1.0.7/lib/bundler/shared_helpers.rb:101:Warning: Gem::LoadError#version_requirement= is deprecated and will be removed on or after January 2011. Use #requirement.
/Users/asari/Development/src/jruby/lib/ruby/gems/1.8/gems/bundler-1.0.7/lib/bundler/shared_helpers.rb:101:Warning: Gem::LoadError#version_requirement= is deprecated and will be removed on or after January 2011. Use #requirement.
/Users/asari/Development/src/jruby/lib/ruby/gems/1.8/gems/bundler-1.0.7/lib/bundler/shared_helpers.rb:101:Warning: Gem::LoadError#version_requirement= is deprecated and will be removed on or after January 2011. Use #requirement.
/Users/asari/Development/src/jruby/lib/ruby/gems/1.8/gems/bundler-1.0.7/lib/bundler/shared_helpers.rb:101:Warning: Gem::LoadError#version_requirement= is deprecated and will be removed on or after January 2011. Use #requirement.
Loading development environment (Rails 3.0.3)
exit
       11.15 real        16.07 user         1.02 sys

`rake environment` timings for a fresh Rails 3 app (`jruby -S rails new myapp -m http://jruby.org/rails3.rb`):

1.5.6:
real 0m5.854s
user 0m6.684s
sys 0m0.421s

1.6.0rc1:
real 0m6.262s
user 0m7.223s
sys 0m0.471s

I get similar timings with Hiro's test command; 1.6.0 RC1 is consistently ~.5s slower.

When profiling this with --profile or --profile.graph, all the time is in Kernel#require/Kernel.load. When profiling it with a Java profiler, a substantial part of the time (~25%) seems to be in java.lang.String.intern() – is that expected?

I would like to add more data regarding rails startup on JRuby.
I have a "real world" Rails 2.3 app using tons of gems. JRuby startup time is about 4 times slower than MRI.
My environment:
Mac OS X 10.7, java 1.6.0_29, RVM 1.9.2, bundler, mri 1.8.7 and jruby 1.6.5

Now the MRI results:

Rubem-Azenhas-MacBook-Pro:portaltrademarketing rubemazenha$ time rake environment

real 0m5.500s
user 0m4.870s
sys 0m0.617s

Now the jruby-1.6.5 results:

Rubem-Azenhas-MacBook-Pro:portaltrademarketing rubemazenha$ time rake environment

real 0m23.382s
user 0m46.954s
sys 0m1.617s

jruby-1.6.5 with -d32 option:

Rubem-Azenhas-MacBook-Pro:portaltrademarketing rubemazenha$ export JAVA_OPTS="-d32"
Rubem-Azenhas-MacBook-Pro:portaltrademarketing rubemazenha$ time rake environment

real 0m17.445s
user 0m21.155s
sys 0m1.009s

The -d32 options really improves the startup time. but it still takes about 40 secs to load my rails app...

There's lots of open bugs about startup time, and we have done things to improve this in every release. More work remains, but we don't need more of these too-general bugs to know that.