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