Advanced Computer Architecture Chapter 7.57
Memory Consistency Model
Weak consistency schemes offer faster execution than sequential consistency
Not really an issue for most programs;
they are synchronized
A program is synchronized if all access to shared data are ordered by synchronization operations
– write (x)
 ...
 release (s) {unlock}
 ...
 acquire (s) {lock}
 ...
 read(x)
Only those programs willing to be nondeterministic are not synchronized: “data race”: outcome f(proc. speed)
Several Relaxed Models for Memory Consistency since most programs are synchronized; characterized by their attitude towards: RAR, WAR, RAW, WAW
to different addresses