RFR(S): 8216556: Unnecessary liveness computation with JVMTI

Doerr, Martin martin.doerr at sap.com
Tue Jan 15 11:05:44 UTC 2019

Hi Vladimir, Dean and Claes,

thank you for reviewing.
I assume the version which moves the implementation of should_retain_local_variables() to the hpp file (as suggested by Claes) is fine.
I'll push this version if there are no objections.

Best regards,

-----Original Message-----
From: hotspot-compiler-dev <hotspot-compiler-dev-bounces at openjdk.java.net> On Behalf Of Doerr, Martin
Sent: Montag, 14. Januar 2019 09:31
To: Claes Redestad <claes.redestad at oracle.com>; 'hotspot-compiler-dev at openjdk.java.net' <hotspot-compiler-dev at openjdk.java.net>
Subject: [CAUTION] RE: RFR(S): 8216556: Unnecessary liveness computation with JVMTI

Hi Claes,

excellent proposal. Thanks. I had not noticed that it currently is in a cpp file.

New webrev:

What I still don't really like is that we're passing MethodLivenessResult objects on stack via 3 compilation units.
But I don't know if it's worth refactoring the code.

Best regards,

-----Original Message-----
From: Claes Redestad <claes.redestad at oracle.com> 
Sent: Freitag, 11. Januar 2019 16:45
To: Doerr, Martin <martin.doerr at sap.com>
Subject: Re: RFR(S): 8216556: Unnecessary liveness computation with JVMTI


  just a random thought, but if you're optimizing this and got some
measure where it matters(?), maybe you should also try inlining
ciEnv::should_retain_local_variables(), i.e., move definition to
ciEnv.hpp. If it doesn't bloat static binary size it seems like it won't
hurt, at least.


On 2019-01-11 13:55, Doerr, Martin wrote:
> Hi,
> I'd like to contribute a small JIT improvement for JVMTI to avoid 
> calling raw_liveness_at_bci when its result is not needed.
> Bug with description:
> https://bugs.openjdk.java.net/browse/JDK-8216556
> Webrev:
> http://cr.openjdk.java.net/~mdoerr/8216556_JVMTI_liveness/webrev.00/
> Please review.
> Best regards,
> Martin

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