MPI Programming Guide

MP_ENABLEINTR, mpc_enableintr

Purpose

Enables message arrival interrupts on a node.

Library

libmpi.a

C synopsis

#include <pm_util.h>
int mpc_enableintr();

FORTRAN synopsis

MP_ENABLEINTR(INTEGER RC)

Parameters

In FORTRAN, RC will contain one of the values listed under Return Values.

Description

This parallel utility subroutine enables message arrival interrupts on the individual node on which it is run. Use this subroutine to dynamically control masking interrupts on a node.

Notes

• This subroutine is only effective when the communication subsystem is active. For the threads library, this is from MPI_INIT to MPI_FINALIZE. For the signal-handling library, which also supports MPL, the communication subsystem is active for the life of the task. If this subroutine is called when the subsystem is inactive, the call will have no effect and the return code will be -1.
• This subroutine overrides the setting of the environment variable MP_CSS_INTERRUPT.
• Inappropriate use of the interrupt control subroutines may reduce performance.
• This subroutine can be used for IP and US protocols.
• This subroutine is thread safe.
• Using this subroutine will suppress the MPI-directed switching of interrupt mode, leaving the user in control for the rest of the run. See MPI_FILE_OPEN and MPI_WIN_CREATE in IBM Parallel Environment for AIX: MPI Subroutine Reference.

Return values

0

indicates successful completion.

-1

indicates that the MPI library was not active. The call was either made before MPI_INIT or after MPI_FINALIZE.

Examples

C Example

/*
 * Running this program, after compiling with mpcc,
 * without setting the MP_CSS_INTERRUPT environment variable,
 * and without using the "-css_interrupt" command-line option,
 * produces the following output:
 *
 *    Interrupts are DISABLED
 *    About to enable interrupts..
 *    Interrupts are ENABLED
 *    About to disable interrupts...
 *    Interrupts are DISABLED
 */
 
#include "pm_util.h"
 
#define QUERY if (intr = mpc_queryintr()) {\
   printf("Interrupts are ENABLED\n");\
  } else {\
   printf("Interrupts are DISABLED\n");\
  }
 
main()
{
 int intr;
 
 QUERY
 
 printf("About to enable interrupts...\n");
 mpc_enableintr();
 
 QUERY
 
 printf("About to disable interrupts...\n");
 mpc_disableintr();
 
 QUERY
}

FORTRAN Example

Running this program, after compiling with mpxlf, without setting the MP_CSS_INTERRUPT environment variable, and without using the "-css_interrupt" command-line option, produces the following output:

      Interrupts are DISABLED
      About to enable interrupts..
      Interrupts are ENABLED
      About to disable interrupts...
      Interrupts are DISABLED
 
 
 
      PROGRAM INTR_EXAMPLE
 
      INTEGER RC
 
      CALL MP_QUERYINTR(RC)
      IF (RC .EQ. 0) THEN
         WRITE(6,*)'Interrupts are DISABLED'
      ELSE
         WRITE(6,*)'Interrupts are ENABLED'
      ENDIF
 
      WRITE(6,*)'About to enable interrupts...'
      CALL MP_ENABLEINTR(RC)
 
      CALL MP_QUERYINTR(RC)
      IF (RC .EQ. 0) THEN
         WRITE(6,*)'Interrupts are DISABLED'
      ELSE
         WRITE(6,*)'Interrupts are ENABLED'
      ENDIF
 
      WRITE(6,*)'About to disable interrupts...'
      CALL MP_DISABLEINTR(RC)
 
      CALL MP_QUERYINTR(RC)
      IF (RC .EQ. 0) THEN
         WRITE(6,*)'Interrupts are DISABLED'
      ELSE
         WRITE(6,*)'Interrupts are ENABLED'
      ENDIF
 
      STOP
      END

Related information

Subroutines:

• MP_DISABLEINTR, mpc_disableintr
• MP_QUERYINTR, mpc_queryintr
• MP_QUERYINTRDELAY, mpc_queryintrdelay
• MP_SETINTRDELAY, mpc_setintrdelay