3.3   Information

• int tid = pvm_parent (void)
call pvmfparent (tid)
  • Returns the tid of the process that spawned this task
  • Or the value PvmNoParent if not created by pvm_spawn()
  • Example

          CALL PVMFPARENT (PTID)
          IF (PTID .EQ. PvmNoParent) THEN 
    C     I have been spawned from the pvm console
    C     or from the shell
    

• int status = pvm_pstat (int tid)
  • Returns the status of a PVM task identified by tid

  • status is	PvmOk if the task is running
    	PvmNoTask if not
    	PvmBadParam if the tid is bad

  • Example

    ptid = pvm_parent () ; 
    status = pvm_stat (ptid) ;                
              

  
  
• int status = pvm_mstat (char *host)

  • Returns	PvmOk if the machine host is running
    	PvmHostFail if host is unreachable
    	PvmNoHost if host is not in the virtual machine

  • Can be useful when implementing application level fault tolerance
  • Example

    status = pvm_mstat ("ms2.ens.lifl.fr") ;                 
    status = pvm_mstat ("ms2") ;                 
              

• int info = pvm_config (int *nhost, int *narch,
   struct hostinfo **hostp)
  • Returns information about the virtual machine
  • Information is similar to that available from the conf command of the pvm console
  • Returns the number of hosts (pvmd) in nhost
  • Returns the number of different data formats being used in narch
  • Returns a pointer to an array of structures which contain information about each host/pvmd

  struct hostinfo { 
     int  hi_tid ;      /* task ID */ 
     char *hi_name ;    /* host machine */
     char *hi_arch ;    /* architecture of the host
                                         machine */
     int hi_speed ;     /* relative speed */
  } ;
        

• Example

  struct hostinfo *hi ; 
  int nh, na ;
  pvm_config (&nh, &na, &hi) ; 
          

• int info = pvm_tasks (int which, int *ntask,
   struct taskinfo **taskp)
  • Returns information about the PVM tasks running on the virtual machine
  • Information is similar to that available by the ps command of the pvm console
  • The integer which specifies the tasks to return information about:
    • 0, which means all tasks
    • A pvm daemon tid, which means tasks running on that host
    • A task tid, which means just the given task
  • The number of tasks is returned in ntask
  • taskp is a pointer to an array of taskinfo structures of size ntask

    struct taskinfo {
        int  ti_tid ;    /* task ID */
        int  ti_ptid ;   /* parent tid */
        int  ti_host ;   /* pvmd tid */
        int  ti_flag ;   /* status flag */
        char *ti_a_out ; /* task executable name */    
    };    
              

  • The flag indicates if the task is waiting for a message, waiting for the pvmd, or running
  • a.out only for ``spawned'' tasks

• Example

  /* info for the tasks on the current host */
  me = pvm_mytid () ; 
  (void) pvm_tasks (me, &nb, &taskp) ;
  (void) pvm_tasks (taskp[0]. ti_host, &nb, &taskp) ;