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Performance of Synchronous Shared Memory

• Implemented using C++ classes for "shared" data types
  • Lvalue store causes s_write() call
  • Rvalue fetch causes s_poll() call (~1 usec)
• Parameters:
  • 32-bit shared memory address
  • 32-bit datum size (in bytes)
  • Arbitrary data values
• For a 32-bit object across 8 386DX33:
  • Read takes ~1 usec
  • Write ranged from 61 to 302 usec
    (32-bit broadcast is ~130 usec!)