To isolate contention problems for shared memory mutexes and condition variables, issue the D OMVS,SER operator command. It will display serialization data that you can use in problem determination.

• Each mutex and condition variable is identified by the shared memory ID and location of the shared memory object.
• If the object is in an above-the-bar shared memory segment, the location information indicates the address of the mutex or condition variable.
• If the object is in a below-the-bar segment, the location information indicates the offset within the shared memory segment. The offset is displayed, in this case, because each address space sharing a below-the-bar segment can map it at a different virtual address.
• For each mutex, the output shows the owner's TCB address, process ID and ASID, and the same for the waiters, if the information can be determined.
• For each condition variable, the output shows the same information for the owner and waiter of the mutex or conditional variable.
• If Language Environment® is the caller of BPX1SMC, the user data represents the address of the Language Environment data area for the waiting or owning task.

If there is no contention, the output will be similar to the following:

BPXO057I 08.51.42 DISPLAY OMVS 284              
OMVS     000E ACTIVE          OMVS=(6D)   
                  UNIX SERIALIZATION REPORT 
NO RESOURCE CONTENTION EXISTS 

If there is contention, the display will be similar to the following:

BPXO0xxI 08.51.42 DISPLAY OMVS 284              
OMVS     000E ACTIVE          OMVS=(6D)         
                              UNIX SERIALIZATION REPORT 
RESOURCE    #1:                                        
  NAME=SHARED MUTEX   DATA: SHMID=00000648 OFFS/ADDR=0000000000002428   

 JOBNAME ASID TCB        PID    USER DATA        EXC/SHR  OWN/WAIT 
 DOMINO1 013A 008EF190 16777220 0000000024780148 EXC    OWN         
 DOMINO2 02B2 008FA190 16908357 0000000024825220 EXC    WAIT 
 DOMINO3 0206 008FF458 16973924 0000000024824778 EXC    WAIT   
RESOURCE    #2:                                        
  NAME=SHARED CONDVAR   DATA: SHMID=00000648 OFFS/ADDR=0000000000002458  
JOBNAME ASID TCB      PID      USER DATA        EXC/SHR  OWN/WAIT 
 DOMINO2 02B6 008FA190 16908357 0000000024825220 EXC    WAIT 
 DOMINO3 0206 008FF458 16973924 0000000024824778 EXC    WAIT
 RESOURCE #0002 IS LOCKED BY: 
  NAME=SHARED MUTEX   DATA: SHMID=00000648 OFFS/ADDR=0000000000002428