[#RVM-375] VM_Static and VM_Atom keys use ~540kb of the boot image

RVM

VM_Static and VM_Atom keys use ~540kb of the boot image

Created: 14/Feb/08 08:58 AM Updated: 09/May/08 09:41 AM

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Runtime

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This issue relates to:

RVM-324 Implement class unloading

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The space requirements for the keys used to access the hashmaps in VM_Atom and VM_Statics use up ~1.5% of the total boot image space (540kb). It would be nice to use a more memory efficient data scheme.

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Ian Rogers - 14/Feb/08 09:00 AM

We need to rethink the class loader data structures to implement class unloading.

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Ian Rogers - 21/Feb/08 06:27 PM

r13978 attempts to do this and clean up VM_Statics, the space savings are:

development data size: -333kb
prototype data size: - 254kb

however, having non-final references added to VM_Atoms to track their corresponding Strings adds:

development reference map size: +16kb
prototype reference map size: +12kb

In terms of the speed changes due to the patch, having a string hanging off the literal avoids a hash map lookup, so the performance effect should be of the same order. The patch also adds literals to the intern table/map, which again could save time.