3.5   Signaling

• int info = pvm_sendsig (int tid, int signum)
  • Sends a Unix signal signum to the PVM task identified by tid
  • Example, on Unix hosts

    pvm_kill (tid) ;
              

    is equivalent to

    pvm_sendsig (tid, SIGKILL) ; 
              

• int info = pvm_notify (int what, int msgtag,
   int ntask, int *tids)
  • Causes a message with a given msgtag to be sent to a set of tasks specified by ntask and tids when some event happen in the virtual machine
  • The argument what specifies the event type:

    PvmTaskExit

     notify if a task exits

    PvmHostDelete

    notify if a host is deleted (or fails)

    PvmHostAdd

    notify if a host is added

  • Message body contains data specific to the event

    PvmTaskExit

    Tid of the task

    PvmHost Delete

    pvmd-tid of the host

    PvmHostAdd

    count of the new hosts and pvmd-tid

  • Example: A console that updates its hostinfo information on each addition/deletion of a host in the virtual machine
    • The console has an initial state of the virtual machine
    • This console will receive a message every time a host is deleted or added
    • Based on the msgtag of his message, updates the state of the virtual machine