issue with GC in RE 1.8.0_275 build

[Srikanth Nayak]

Hi All,

Below are the details about the issue with JRE 1.8.0_275 build.
-GC is not executing as expected.

Platform: Mac OS X (mojave, catalina etc)

JRE-1:(Open JDK)
openjdk version "1.8.0_275"
OpenJDK Runtime Environment (build 1.8.0_275-b01)
Eclipse OpenJ9 VM (build openj9-0.23.0, JRE 1.8.0 Mac OS X amd64-64-Bit
20201112_584 (JIT enabled, AOT enabled)
OpenJ9   - 0394ef754
OMR      - 582366ae5
JCL      - b52d2ff7ee based on jdk8u275-b01)

JRE-2:(IBM JDK)
java version "1.8.0_181"
Java(TM) 2 Runtime Environment, Standard Edition (IBM build 1.8.0_181-b13
25_Jul_2018_11_11 Mac OS X x64(SR5 FP20))
Java HotSpot(TM) 64-Bit Server VM (build 25.181-b13, mixed mode)
IBM Java ORB build orb80-20180617.00
XML build XL TXE Java 1.0.60
XML build IBM JAXP 1.6.1
XML build XML4J 4.5.30


gcpolicy: concurrentScavenge
(tried with default gencon too)

Problem:
with JRE-1 which we use with our application.
-GC is not executing as expected.
-There is a significant increase in memory even when the application is
idle.
-performing tests causes an increase in memory - but not released as
expected.

when using JRE-2 shows significant advantage compared to JRE-1 with our
application.

Analysis:
Testing scenario: 1
JRE-1:
starting our application in consumes: 292.0MB
leave application idle for 1 hour: 28.9MB CONSUMED
After testing and final memory will be: 693.5MB


Testing scenario: 2
JRE-2:
starting our application in consumes: 486.7MB
leave application idle for 1 hour: 7.7MB RELEASED
After testing and final memory will be: 315.1MB

-Testing scenarios are the same.
-Mac OS X is installed in the VM environment for testing.
-Our application is a standalone application which runs on Mac as well as
Windows.
-The issue is not seen with the Windows version of JRE.

can you please help with the issue so that we can continue with JRE-1 ?
-- 
*Regards,*
*𝓢𝓻𝓲𝓴𝓪𝓷𝓽𝓱. 𝓢*



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