Class Data Sharing and Compiler Dependency

Coleen Phillimore coleen.phillimore at
Mon Jul 2 08:15:17 PDT 2012

Today CDS (Class Data Sharing) is only supported UseSerialGC, which is 
almost never used for the server compiler (COMPILER2).   The original 
conditional code was intended to do that, then TIERED got added.

In the PermGen elimination work, CDS is supported for all GCs so this 
conditional code needs to be cleaned up.  Thanks for pointing it out.


On 7/2/2012 3:56 AM, David Holmes wrote:
> On 2/07/2012 4:34 PM, jam tech wrote:
>> i see class data sharing disabled for COMPILER2(in arguments.cpp) . 
>> can any
>> one help me knowing why its disabled for COMPILER2 , while its 
>> enabled in
>> COMPILER1 , TIERED cases ?
> AFAICS it is only -Xshare:dump that is "disabled"
> This is not an authoritive history but ...
> - CDS was initially only intended for client VM and not supported on 
> server
> - early TIERED compilation work enabled CDS
> - hotspot has actually been building TIERED rather the COMPILER2 for a 
> while now
> David

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