A significant percentage of heap memory in a 64 bit JavaVM is used by references, that are 8 bytes long. To reduce this problem they have invented "compressed references" (useful only for 64 bit systems), that turn references to 32 bit again:
https://blogs.oracle.com/jrockit/entry/understanding_compressed_refer ftp://public.dhe.ibm.com/software/webserver/appserv/was/WAS_V7_64-bit_performance.pdf With them the total amount of heap memory decreases. They don't slow down the class usage significantly, and the memory reduction reduces the CPU cache pressure, increasing the performance a bit. Will this idea be useful for 64 bit D/DMD too, for D GC-managed class references (not for raw pointers)? Bye, bearophile
