1. It’s the Software, Stupid James Larus Microsoft Research April 2005

2. Transactional Memory Promising abstraction for concurrent programming –CMPs bring problems to the forefront Mechanism lives in software environment –simple “hardware” transactions may not provide appropriate semantics

3. Example 1: Conflicting Abstractions Code

4. Example 1: Conflicting Abstractions Code Transactional Memory

5. Example 1: Conflicting Abstractions Code GC

6. Example 1: Conflicting Abstractions Code TM GC TM

7. Example 2: Nested Transactions Code LibrariesComponents

8. What is abstraction boundary? Can library hide internal user of concurrency? Example 2: Nested Transactions Code LibrariesComponents Libraries Code

9. DB Example 3: IO Code TM

10. Summary Not starting with a clean slate TM must work within existing environment –changes to use TM will be large –unrealistic to change everything at once