[prev in list] [next in list] [prev in thread] [next in thread] 

List:       openjdk-serviceability-dev
Subject:    RE: RFR(L) 8227745: Enable Escape Analysis for Better Performance in the Presence of JVMTI Agents
From:       "Reingruber, Richard" <richard.reingruber () sap ! com>
Date:       2019-12-23 9:40:52
Message-ID: DB7PR02MB361224E2C0B8932C73C8A24A9B2E0 () DB7PR02MB3612 ! eurprd02 ! prod ! outlook ! com
[Download RAW message or body]

Hi,

webrev.3 didn't apply anymore after 8236000 [1]. I've rebased and updated in place:

http://cr.openjdk.java.net/~rrich/webrevs/2019/8227745/webrev.3/

The change was minimal.

Cheers, Richard.

[1] JDK-8236000: VM build without C2 fails

-----Original Message-----
From: Reingruber, Richard 
Sent: Dienstag, 10. Dezember 2019 22:45
To: serviceability-dev@openjdk.java.net; hotspot-compiler-dev@openjdk.java.net; \
                hotspot-runtime-dev@openjdk.java.net
Subject: RFR(L) 8227745: Enable Escape Analysis for Better Performance in the \
Presence of JVMTI Agents

Hi,

I would like to get reviews please for

http://cr.openjdk.java.net/~rrich/webrevs/2019/8227745/webrev.3/

Corresponding RFE:
https://bugs.openjdk.java.net/browse/JDK-8227745

Fixes also https://bugs.openjdk.java.net/browse/JDK-8233915
And potentially https://bugs.openjdk.java.net/browse/JDK-8214584 [1]

Vladimir Kozlov kindly put webrev.3 through tier1-8 testing without issues (thanks!). \
In addition the change is being tested at SAP since I posted the first RFR some \
months ago.

The intention of this enhancement is to benefit performance wise from escape analysis \
even if JVMTI agents request capabilities that allow them to access local variable \
values. E.g. if you start-up with \
-agentlib:jdwp=transport=dt_socket,server=y,suspend=n, then escape analysis is \
disabled right from the beginning, well before a debugger attaches -- if ever one \
should do so. With the enhancement, escape analysis will remain enabled until and \
after a debugger attaches. EA based optimizations are reverted just before an agent \
acquires the reference to an object. In the JBS item you'll find more details.

Thanks,
Richard.

[1] Experimental fix for JDK-8214584 based on JDK-8227745
    http://cr.openjdk.java.net/~rrich/webrevs/2019/8214584/experiment_v1.patch


[prev in list] [next in list] [prev in thread] [next in thread]