LogTM: Logbased Transactional Memory Kevin E' Moore, et al' International Symposium on High Performa

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LogTM Log-based Transactional MemoryKevin E.
Moore, et al.International Symposium on High
Performance Computer Architecture (HPCA-12),
Austin, TX, February 2006

• Goals
• eager version management when xactions overflow
• Approach
• extend directory protocol for fast conflict
  detection

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Protocol HW Modifications

• per-processor overflow bit
• per-thread transaction log to checkpoint mem
  state
• extended directory protocol to include sticky
  states
• blocks in sticky states are potential xaction
  overflows
• also using overflow bit, detect conflict w/
  remote requestsmay end up with false positives
  in rare situations, but still correct
• log is never used to detect conflict
• software abort handler
• shadow register file to checkpoint register state