0 Replies Latest reply: Nov 18, 2009 2:04 PM by 843829 RSS

    Empty MEMBAR-acquire/MEMBAR-release block

    843829
      Hello,

      When there are no instructions between MEMBAR-acquire and MEMBAR-release, does that mean synchronization is elided? What purpose do they serve if they contain no code in between them?
      051   B3: #     B8 B4 <- B7 B6 B2 B14  Freq: 1
      051        MEMBAR-acquire (prior CMPXCHG in FastLock so empty encoding)
      051        MEMBAR-release ! (empty encoding)
      051        MOV    ECX,#7
      056        AND    ECX,[EBP]
      059        CMP    ECX,#5
      05c        Jne,s  B8  P=0.000001 C=-1.000000
      05c
      05e   B4: #     N152 <- B9 B8 B3  Freq: 1
      05e        MOV    EAX,#120
      063        ADD    ESP,24     # Destroy frame
           POPL   EBP
           TEST   PollPage,EAX     ! Poll Safepoint
           
      06d        RET
      Regards,
      Vijay