RFR (L): 8015774: Add support for multiple code heaps

Vladimir Kozlov vladimir.kozlov at oracle.com
Tue Apr 15 17:56:31 UTC 2014


On 4/15/14 1:00 AM, Tobias Hartmann wrote:
> Hi Vladimir,
>
> On 04/14/2014 11:38 PM, Vladimir Kozlov wrote:
>> Code seems okay. I assume it is mostly (functionally) the same we
>> reviewed several months ago. Right?
>
> Yes, it is. I mostly worked on the second patch (dynamic resizing) and
> only did some refactoring and fixes.
>
>> One thing is bothering me is codecache structure expose to outside
>> code (loop in compileBroker.cpp, nmethod.cpp and
>> jvmtiCodeBlobEvents.cpp).
>> It would be nice to hide it.
>
> Yes, that's a little bit ugly. Do you think using an iterator is a good
> idea?

You do need a loop. So some kind of iterator is needed which works over 
section which contains compiled methods.

Vladimir

>
>> Before pushing it we need to test. SA, dtrace and other components are
>> affected by these changes. Ask sqe and performance group for help.
>
> Okay, I will talk to them.
>
> Thanks,
> Tobias
>
>>
>> Thanks,
>> Vladimir
>>
>> On 4/14/14 6:05 AM, Tobias Hartmann wrote:
>>> Hi Volker,
>>>
>>> please see comments inline.
>>>
>>> On 04/14/2014 02:54 PM, Volker Simonis wrote:
>>>> Hi Tobias,
>>>>
>>>> is this change intended for jdk8 or 9?
>>>
>>> the change is intended for JDK 9. The webrev is based on the JDK 9
>>> repository (http://hg.openjdk.java.net/jdk9/hs-comp/hotspot)
>>> changeset 6280.
>>>
>>>>   In any case, I saw that your
>>>> webrev is based on the hsx repository which I thought should not be
>>>> used any more.
>>>
>>> Why do you think that it is based on hsx? The earlier versions 00 - 03
>>> actually were, because I already started developing the patch last year,
>>> but the newest one is based on the JDK 9 repository.
>>>
>>> As Roland noticed, the default code heap sizes for arm/ppc were wrong
>>> (because tiered compilation is supported). The updated webrev can be
>>> found at:
>>>
>>> http://cr.openjdk.java.net/~anoll/8015774/webrev.05/
>>> <http://cr.openjdk.java.net/%7Eanoll/8015774/webrev.05/>
>>>
>>> Thanks,
>>> Tobias
>>>
>>>> Could you please rebase your patch on jdk9 and also
>>>> update the corresponding ppc64 files in the webrev (as far as I can
>>>> see, that's only src/cpu/ppc/vm/c2_globals_ppc.hpp). I'd like to test
>>>> this on Linux/PPC64 and AIX as well.
>>>>
>>>> Thank you and best regards,
>>>> Volker
>>>>
>>>>
>>>>
>>>> On Mon, Apr 14, 2014 at 1:56 PM, Tobias Hartmann
>>>> <Tobias.Hartmann at oracle.com>  wrote:
>>>>> Hi,
>>>>>
>>>>> please review the new version of the following patch that adds
>>>>> support for
>>>>> multiple code heaps to the code cache.
>>>>>
>>>>> Bug:https://bugs.openjdk.java.net/browse/JDK-8015774
>>>>> Webrev:http://cr.openjdk.java.net/~anoll/8015774/webrev.04/
>>>>>
>>>>> Short description:
>>>>> This change implements support for multiple code heaps in the code
>>>>> cache.
>>>>> The interface of the code cache was changed accordingly and
>>>>> references from
>>>>> other components of the VM were adapted. This includes the indirect
>>>>> references from:
>>>>> - the Serviceability Agent: vmStructs and the Java code cache
>>>>> interface
>>>>> (sun.jvm.hotspot.code.CodeCache)
>>>>> - the dtrace ustack helper script (jhelper.d)
>>>>> - the pstack support library libjvm_db.c
>>>>>
>>>>> Currently the code cache contains the following three code heaps
>>>>> each of
>>>>> which contains CodeBlobs of a specific type:
>>>>> - Non-Profiled methods: nmethods that are not profiled and native
>>>>> methods
>>>>> - Profiled methods: nmethods that are profiled
>>>>> - Non-methods: Non-methods like buffers and adapters
>>>>>
>>>>> By default the non-method code heap uses 3 MB plus additional space
>>>>> for the
>>>>> compiler buffers that is dependent on the number of compiler
>>>>> threads (see
>>>>> CodeCache::initialize_heaps). The remaining code cache space is
>>>>> distributed
>>>>> equally among the non-profiled and the profiled code heaps.
>>>>>
>>>>> Tested:
>>>>> JPRT, SPECjvm2008, SPECjbb2005, SPECjbb2013, Octane + Nashorn
>>>>>
>>>>> Thanks,
>>>>> Tobias
>>>>>
>>>>>
>>>>> -------- Original Message --------
>>>>> Subject: Re: RFR (L): 8015774: Add support for multiple code heaps
>>>>> Date: Mon, 21 Oct 2013 17:47:48 +0200
>>>>> From: Albert Noll<albert.noll at oracle.com>
>>>>> To: Azeem Jiva<azeem.jiva at oracle.com>
>>>>>
>>>>>
>>>>> That is fine. As we realized the last two weeks, there is more work
>>>>> to be
>>>>> done to make multiple code heaps work effectively.
>>>>>
>>>>> Albert
>>>>>
>>>>> Von meinem iPhone gesendet
>>>>>
>>>>> Am 21.10.2013 um 17:36 schrieb Azeem Jiva<azeem.jiva at oracle.com>:
>>>>>
>>>>> I still think we should hold off for JDK8u20
>>>>>
>>>>> --
>>>>> Azeem Jiva
>>>>> @javawithjiva
>>>>>
>>>>> On Oct 21, 2013, at 8:33 AM, Albert Noll<albert.noll at oracle.com>
>>>>> wrote:
>>>>>
>>>>>
>>>>> Von meinem iPhone gesendet
>>>>>
>>>>> Anfang der weitergeleiteten E‑Mail:
>>>>>
>>>>> Von: Vladimir Kozlov<vladimir.kozlov at oracle.com>
>>>>> Datum: 11. Oktober 2013 19:38:07 MESZ
>>>>> An:hotspot-compiler-dev at openjdk.java.net
>>>>> Betreff: Re: RFR (L): 8015774: Add support for multiple code heaps
>>>>>
>>>>> This looks acceptable.
>>>>>
>>>>> Thanks,
>>>>> Vladimir
>>>
>


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