RFR: 8204210: Implementation: JEP 333: ZGC: A Scalable Low-Latency Garbage Collector (Experimental)

Tue Jun 12 17:59:44 UTC 2018

Hi,

Just an updated to say that we've now pushed ZGC to jdk/jdk.

cheers,
Per

On 06/08/2018 08:20 PM, Per Liden wrote:
> Hi all,
> 
> Here are updated webrevs, which address all the feedback and comments 
> received. These webrevs are also rebased on today's jdk/jdk. We're 
> looking for any final comments people might have, and if things go well 
> we hope to be able to push this some time (preferably early) next week.
> 
> These webrevs have passed tier{1,2,3,4,5,6} on Linux-x64, and 
> tier{1,2,3} on all other Oracle supported platforms.
> 
> ZGC Master
>    http://cr.openjdk.java.net/~pliden/8204210/webrev.2-master
> 
> ZGC Testing
>    http://cr.openjdk.java.net/~pliden/8204210/webrev.2-testing
> 
> Thanks!
> 
> /Per & Stefan
> 
> 
> On 06/06/2018 12:48 AM, Per Liden wrote:
>> Hi all,
>>
>> Here are updated webrevs reflecting the feedback received so far.
>>
>> ZGC Master
>>    Incremental: 
>> http://cr.openjdk.java.net/~pliden/8204210/webrev.0vs1-master
>>    Full: http://cr.openjdk.java.net/~pliden/8204210/webrev.1-master
>>
>> ZGC Testing
>>    Incremental: 
>> http://cr.openjdk.java.net/~pliden/8204210/webrev.0vs1-testing
>>    Full: http://cr.openjdk.java.net/~pliden/8204210/webrev.1-testing
>>
>> Thanks!
>>
>> /Per
>>
>> On 06/01/2018 11:41 PM, Per Liden wrote:
>>> Hi,
>>>
>>> Please review the implementation of JEP 333: ZGC: A Scalable 
>>> Low-Latency Garbage Collector (Experimental)
>>>
>>> Please see the JEP for more information about the project. The JEP is 
>>> currently in state "Proposed to Target" for JDK 11.
>>>
>>> https://bugs.openjdk.java.net/browse/JDK-8197831
>>>
>>> Additional information in can also be found on the ZGC project wiki.
>>>
>>> https://wiki.openjdk.java.net/display/zgc/Main
>>>
>>>
>>> Webrevs
>>> -------
>>>
>>> To make this easier to review, we've divided the change into two 
>>> webrevs.
>>>
>>> * ZGC Master: http://cr.openjdk.java.net/~pliden/8204210/webrev.0-master
>>>
>>>    This patch contains the actual ZGC implementation, the new unit 
>>> tests and other changes needed in HotSpot.
>>>
>>> * ZGC Testing: 
>>> http://cr.openjdk.java.net/~pliden/8204210/webrev.0-testing
>>>
>>>    This patch contains changes to existing tests needed by ZGC.
>>>
>>>
>>> Overview of Changes
>>> -------------------
>>>
>>> Below follows a list of the files we add/modify in the master patch, 
>>> with a short summary describing each group.
>>>
>>> * Build support - Making ZGC an optional feature.
>>>
>>>    make/autoconf/hotspot.m4
>>>    make/hotspot/lib/JvmFeatures.gmk
>>>    src/hotspot/share/utilities/macros.hpp
>>>
>>> * C2 AD file - Additions needed to generate ZGC load barriers (adlc 
>>> does not currently offer a way to easily break this out).
>>>
>>>    src/hotspot/cpu/x86/x86.ad
>>>    src/hotspot/cpu/x86/x86_64.ad
>>>
>>> * C2 - Things that can't be easily abstracted out into ZGC specific 
>>> code, most of which is guarded behind a #if INCLUDE_ZGC and/or if 
>>> (UseZGC) condition. There should only be two logic changes (one in 
>>> idealKit.cpp and one in node.cpp) that are still active when ZGC is 
>>> disabled. We believe these are low risk changes and should not 
>>> introduce any real change i behavior when using other GCs.
>>>
>>>    src/hotspot/share/adlc/formssel.cpp
>>>    src/hotspot/share/opto/*
>>>    src/hotspot/share/compiler/compilerDirectives.hpp
>>>
>>> * General GC+Runtime - Registering ZGC as a collector.
>>>
>>>    src/hotspot/share/gc/shared/*
>>>    src/hotspot/share/runtime/vmStructs.cpp
>>>    src/hotspot/share/runtime/vm_operations.hpp
>>>    src/hotspot/share/prims/whitebox.cpp
>>>
>>> * GC thread local data - Increasing the size of data area by 32 bytes.
>>>
>>>    src/hotspot/share/gc/shared/gcThreadLocalData.hpp
>>>
>>> * ZGC - The collector itself.
>>>
>>>    src/hotspot/share/gc/z/*
>>>    src/hotspot/cpu/x86/gc/z/*
>>>    src/hotspot/os_cpu/linux_x86/gc/z/*
>>>    test/hotspot/gtest/gc/z/*
>>>
>>> * JFR - Adding new event types.
>>>
>>>    src/hotspot/share/jfr/*
>>>    src/jdk.jfr/share/conf/jfr/*
>>>
>>> * Logging - Adding new log tags.
>>>
>>>    src/hotspot/share/logging/*
>>>
>>> * Metaspace - Adding a friend declaration.
>>>
>>>    src/hotspot/share/memory/metaspace.hpp
>>>
>>> * InstanceRefKlass - Adjustments for concurrent reference processing.
>>>
>>>    src/hotspot/share/oops/instanceRefKlass.inline.hpp
>>>
>>> * vmSymbol - Disabled clone intrinsic for ZGC.
>>>
>>>    src/hotspot/share/classfile/vmSymbols.cpp
>>>
>>> * Oop Verification - In four cases we disabled oop verification 
>>> because it do not makes sense or is not applicable to a GC using load 
>>> barriers.
>>>
>>>    src/hotspot/cpu/x86/c1_LIRAssembler_x86.cpp
>>>    src/hotspot/cpu/x86/stubGenerator_x86_64.cpp
>>>    src/hotspot/share/compiler/oopMap.cpp
>>>    src/hotspot/share/runtime/jniHandles.cpp
>>>
>>> * StackValue - Apply a load barrier in case of OSR. This is a bit of 
>>> a hack. However, this will go away in the future, when we have the 
>>> next iteration of C2's load barriers in place (aka "C2 late barrier 
>>> insertion").
>>>
>>>    src/hotspot/share/runtime/stackValue.cpp
>>>
>>> * JVMTI - Adding an assert() to catch problems if the tagmap hashing 
>>> is changed in the future.
>>>
>>>    src/hotspot/share/prims/jvmtiTagMap.cpp
>>>
>>> * Legal - Adding copyright/license for 3rd party hash function used 
>>> in ZHash.
>>>
>>>    src/java.base/share/legal/c-libutl.md
>>>
>>> * SA - Adding basic ZGC support.
>>>
>>>    src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/*
>>>
>>>
>>> Testing
>>> -------
>>>
>>> * Unit testing
>>>
>>>    A number of new ZGC specific gtests have been added, in 
>>> test/hotspot/gtest/gc/z/
>>>
>>> * Regression testing
>>>
>>>    No new failures in Mach5, with ZGC enabled, tier{1,2,3,4,5,6}
>>>    No new failures in Mach5, with ZGC disabled, tier{1,2,3}
>>>
>>> * Stress testing
>>>
>>>    We have been continuously been running a number stress tests 
>>> throughout the development, these include:
>>>
>>>      specjbb2000
>>>      specjbb2005
>>>      specjbb2015
>>>      specjvm98
>>>      specjvm2008
>>>      dacapo2009
>>>      test/hotspot/jtreg/gc/stress/gcold
>>>      test/hotspot/jtreg/gc/stress/systemgc
>>>      test/hotspot/jtreg/gc/stress/gclocker
>>>      test/hotspot/jtreg/gc/stress/gcbasher
>>>      test/hotspot/jtreg/gc/stress/finalizer
>>>      Kitchensink
>>>
>>>
>>> Thanks!
>>>
>>> /Per, Stefan & the ZGC team