Pharo9: 65,8 MB
Pharo10: 57,4 MB
Pharo11: 56,5 MB
The space saving come from three things:
1) Code cleanup Pharo9-Pharo10
=========================
e.g. removal of support in Kernel and Compiler of old style blocks and
bytecodes,
to mention one smaller (in term of image size) but deep cleanup.
Of course, we can do more here. There is still a lot of dead code (and
duplicated
things) in the image!
2) Global Literal Sharing
===================
Literals are now, when the method is compiled, set to be read-only, recursively
in the case of arrays.
This allows us to unify (share one instance) not only in the same method, but
globally over all methods.
As the compiler can not do a global literal table when compiling a single
method (too slow), this is implemented
as an additional pass, called as part of the build process.
If you load a lot of code, it might be an idea to do that as part of your build
again:
ImageCleaner shareLiterals
3) Improvement of code structure objects
===============================
e.g, in Pharo10 we found two empty OrderedCollections per class that where not
needed.
Further work on this idea is where the improvement in Pharo11 comes from, we
merged these three changes:
- Class>>#classPool: empty dictionary for all classes, but not many define
class vars #11172
https://github.com/pharo-project/pharo/issues/11172
- [Memory] sharedPools OrderedCollections waste memory #10957
https://github.com/pharo-project/pharo/issues/10957
- [Memory] AllProtocol uses a lot of memory #10963
https://github.com/pharo-project/pharo/issues/10963
The classPools/sharedPool improves the size of the bootstrapped image not to0
much as the boostrap creates
classes with nil there, but for newly loaded code this will be more visible.
This direction has some more fairly simple next steps:
- [Memory] commentSourcePointer is not needed for MetaClasses
https://github.com/pharo-project/pharo/issues/10958
- [Memory] Every class and meta class has both a ProtocolOrganizer and a
ClassOrganization #10959
https://github.com/pharo-project/pharo/issues/10959
... and of course there are many more things to find with just looking a bit.
(And it is interesting starting point to think about better language support
for making long living but rarely changed
data structures more memory efficient)
If you want to get an impression of which classes use image space, "SpaceTally
printSpaceAnalysis"
prints a per-class analysis.
Marcus
