JRuby base startup under Hotspot and OpenJ9 (with OpenJDK 8)

gistfile1.txt

Hotspot:

root@87006c934ea0:~/jruby# time jruby -e 1

real	0m1.469s
user	0m3.440s
sys	0m0.210s

root@87006c934ea0:~/jruby# time jruby -e 1

real	0m1.470s
user	0m3.310s
sys	0m0.160s

root@87006c934ea0:~/jruby# time jruby --dev -e 1

real	0m1.185s
user	0m1.610s
sys	0m0.130s

root@87006c934ea0:~/jruby# time jruby --dev -e 1

real	0m1.151s
user	0m1.500s
sys	0m0.220s

OpenJ9:

root@87006c934ea0:~/jruby# time jruby -e 1

real	0m2.568s
user	0m3.840s
sys	0m0.600s

root@87006c934ea0:~/jruby# time jruby -e 1

real	0m2.489s
user	0m4.010s
sys	0m0.330s

root@87006c934ea0:~/jruby# time jruby -J-Xquickstart -e 1

real	0m1.798s
user	0m2.680s
sys	0m0.110s

root@87006c934ea0:~/jruby# time jruby -J-Xquickstart -e 1

real	0m1.797s
user	0m2.710s
sys	0m0.080s

root@87006c934ea0:~/jruby# time jruby -J-Xquickstart -J-Xshareclasses -e 1

real	0m2.562s
user	0m3.630s
sys	0m0.890s

root@87006c934ea0:~/jruby# time jruby -J-Xquickstart -J-Xshareclasses -e 1

real	0m1.423s
user	0m1.910s
sys	0m0.150s

root@87006c934ea0:~/jruby# time jruby -J-Xquickstart -J-Xshareclasses -e 1

real	0m1.312s
user	0m1.750s
sys	0m0.060s

Can you run with java -Xshareclasses:destroy to destroy the current sharedclasses cache? The default sized cache is fairly small and jruby fills it up.

If you run with time ./jruby -J-Xshareclasses -J-Xscmx100m -J-Xquickstart -e 1 after destroying the cache? This creates a large cache and uses quickstart. Check the numbers after a couple of runs to ensure that the rom classes / aot code has been stored.

You can also check how full the cache is using -Xsharedclasses:printStats or -Xsharedclasses:printAllStats.