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

Tobias Hartmann Tobias.Hartmann at oracle.com
Mon Apr 14 11:56:53 UTC 2014


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 
- 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.
JPRT, SPECjvm2008, SPECjbb2005, SPECjbb2013, Octane + Nashorn


-------- 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.


Von meinem iPhone gesendet

Am 21.10.2013 um 17:36 schrieb Azeem Jiva <azeem.jiva at oracle.com 
<mailto: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 
> <mailto:albert.noll at oracle.com>> wrote:
>> Von meinem iPhone gesendet
>> Anfang der weitergeleiteten E‑Mail:
>>> *Von:* Vladimir Kozlov <vladimir.kozlov at oracle.com 
>>> <mailto:vladimir.kozlov at oracle.com>>
>>> *Datum:* 11. Oktober 2013 19:38:07 MESZ
>>> *An:* hotspot-compiler-dev at openjdk.java.net 
>>> <mailto: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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