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

Tue Jun 12 18:16:06 UTC 2018

Woohoo! Congratulations!
Cheers,
Roman

> 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