Single byte Atomic::cmpxchg implementation

Erik Österlund erik.osterlund at
Thu Sep 4 09:05:13 UTC 2014


The implementation of single byte Atomic::cmpxchg on x86 (and all other platforms) emulates the single byte cmpxchgb instruction using a loop of jint-sized load and cmpxchgl and code to dynamically align the destination address.

This code is used for GC-code related to remembered sets currently.

I have the changes on my platform (amd64, bsd) to simply use the native cmpxchgb instead but could provide a patch fixing this unnecessary performance glitch for all supported x86 if anybody wants this?


More information about the hotspot-dev mailing list