STATIC SOFTWARE SCHEMES Version control

Version control

• Cheong and Veidenbaum 1989, Univ. of Illinois

• Scheme is based on the static analysis of the parallel program tasking structure, and a dynamic control of the variable version

• Two counters for each variable:

  • Current Version Number (CVN) in private memory, and
  • Birth Version Number (BVN) in cache line

• BVN:=CVN , on cache read miss

• BVN:=CVN+1 , on cache write (next version)

• Compiler inserts CVN:=CVN+1 at the end of the task level for all variables being written.

• If BVN<, => miss