Making PrintEscapeAnalysis a diagnostic option on product VM?

Vitaly Davidovich vitalyd at
Fri Jun 19 11:09:29 UTC 2015

I think I had made a similar request a couple of years ago or so on this
list.  Personally, I'd find output to tty useful, akin to PrintInlining.
LogCompilation is useful for tools, but basic diagnostic output for human
consumption would be great.

Also, now that superword is seeing some love, it'd be nice to have
diagnostic output for vectorization (i.e. loop xyz vectorized, not
vectorized due to ..., etc).


sent from my phone
On Jun 19, 2015 7:03 AM, "Vladimir Ivanov" <vladimir.x.ivanov at>

> Chris,
> I'd suggest to look into enhancing LogCompilation output instead of
> parsing VM output. It doesn't require any flag changes and fits nicely into
> existing LogCompilation functionality, so we can integrate it into the
> product, relieving you and JITWatch users from building a companion VM.
> Best regards,
> Vladimir Ivanov
> On 6/19/15 1:16 PM, Chris Newland wrote:
>> Hi, hope this is the correct list (perhaps serviceability?)
>> I'm experimenting with some HotSpot changes that log escape analysis
>> decisions so that I can visualise eliminated allocations at the source and
>> bytecode levels in JITWatch[1].
>> My plan was to build a companion VM for JITWatch based on the product VM
>> that would allow users to inspect some of the deeper workings such as EA
>> and DCE that are not present in the LogCompilation output.
>> I mentioned this to some performance guys at Devoxx and they didn't like
>> the custom VM idea and suggested I put in a request to consider making
>> -XX:+PrintEscapeAnalysis available under -XX:+UnlockDiagnosticVMOptions on
>> the product VM (it's currently a notproduct option).
>> If this is something you would consider than could I also request
>> consideration of -XX:+PrintEliminateAllocations.
>> All I would need is the class, method, and bci of each NoEscape detected.
>> Kind regards,
>> Chris
>> [1]
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