Eclipse OpenJ9 – Open-source JVM

Re:Eclipse OpenJ9 – Open-source JVM by kimi on Sunday September 17, 2017 @03:01AM (#15268563)

I tried some quick tests using a fully AOT, short-running thing we run in house. Here the cost is the set-up of JVM and loading of Clojure stuff (CentOS 7 Vagrant VM on my Mac).

J9:

time ./jdk-9+181/bin/java -client -jar l2i-0.1.0-SNAPSHOT-standalone.jar

real 0m1.987s user 0m3.383s sys 0m0.161s

time ./jdk-9+181/bin/java -server -jar l2i-0.1.0-SNAPSHOT-standalone.jar

real 0m2.949s user 0m5.452s sys 0m0.167s

OpenJDK 8:

[root@localhost ~]# time java -server -jar l2i-0.1.0-SNAPSHOT-standalone.jar

real 0m1.545s user 0m2.510s sys 0m0.175s

time java -client -jar l2i-0.1.0-SNAPSHOT-standalone.jar

real 0m1.456s user 0m2.309s sys 0m0.182s

----

For whatever it means, this is a repeated execution of 10 runs together for J9:

real 0m17.341s user 0m26.783s sys 0m1.344s

And this is the same thing for openjdk version "1.8.0_144"

real 0m15.169s user 0m24.573s sys 0m1.711s

So I'd say that the answer to your question is is no, they are in the same class for a short-running Clojure app dominated by startup times, unless there is some special tweak.

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Re:Eclipse OpenJ9 – Open-source JVM by ShroudedNight on Sunday September 17, 2017 @04:05AM (#15268700)

The OpenJ9 infrastructure is somewhat different [for the better] than what I'm used to using internally, but I have only ever seen the shared class cache enabled when the -Xshareclasses [1] option is passed to the JVM. Do these numbers change significantly (especially after a warm-up run) if you add that option to J9's option set?

[1] https://www.ibm.com/support/knowledgecenter/en/SSYKE2_8.0.0/...

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Re:Eclipse OpenJ9 – Open-source JVM by kimi on Sunday September 17, 2017 @11:54AM (#15270171)

see above

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Re:Eclipse OpenJ9 – Open-source JVM by kimi on Sunday September 17, 2017 @11:53AM (#15270168)

Changes with Quickstart and Sharedclasses;

# time for i in `seq 1 10`; do ./jdk-9+181/bin/java -client -Xquickstart -jar l2i-0.1.0-SNAPSHOT-standalone.jar; done

real 0m18.571s user 0m30.429s sys 0m1.374s

# time for i in `seq 1 10`; do ./jdk-9+181/bin/java -client -Xshareclasses -jar l2i-0.1.0-SNAPSHOT-standalone.jar; done

real 0m16.642s user 0m19.483s sys 0m6.307s

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Re:Eclipse OpenJ9 – Open-source JVM by mstoodle on Monday September 18, 2017 @02:05AM (#15273692)

You're showing the sum of all times, but do the times at least look better after the first run (with -Xshareclasses anyway) ?

Depending on how smoothly your experimentation went, you may also have to destroy a pre-existing cache before you really measure it (java -Xshareclasses:destroy) as it could have stale classes in it from an earlier run.

Would you be willing to open an issue with more details at http://github.com/eclipse/openj9/issues so we can look into it?

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Re:Eclipse OpenJ9 – Open-source JVM by stewbrew on Sunday September 17, 2017 @03:40AM (#15268648)

Maybe I'm missing something or I'm just blind but where is there AOT compilation in your example since you seem to run the same jar with the same command-line options.

That said I'm not that surprised that class aot compilation didn't really speed up a clojure app.

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Re:Eclipse OpenJ9 – Open-source JVM by kimi on Sunday September 17, 2017 @11:54AM (#15270179)

The Clojure app was AOT compiled (Clojure->bytecode) not the JVM's AOT

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Re:Eclipse OpenJ9 – Open-source JVM by floatboth on Sunday September 17, 2017 @10:27AM (#15269744)

Apparently there's an option in J9 called -Xquickstart, have you tried that?

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Re:Eclipse OpenJ9 – Open-source JVM by kimi on Sunday September 17, 2017 @11:55AM (#15270181)

see above

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Re:Eclipse OpenJ9 – Open-source JVM by ledgerdev on Sunday September 17, 2017 @03:42AM (#15268650)

Thanks for checking, even if the result is not as we hoped.

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