Hybrid Hardware/Software Implementation

• Hardware transaction implementation is very fast! But it is limited:

  • Slow once you exceed cache capacity
  • Transaction lifetime limits (context switches)
  • Limited semantic flexibility (nesting, etc)

• Software transaction implementation is unlimited and very flexible!

  • But transactions may be slow

• Solution: failover from hardware to software

  • Simplest mechanism: after first hardware abort, execute transaction in software
  • Need to ensure that the two algorithms play nicely with each other (consistent views)  see next slide...

Notes: