/*
     * Copyright (c) 2002 by Ali Onur Cinar <cinar(a)zdo.com>
     *
     * Desc    : Process binding to different CPUs
     * --
     * System  : Compaq ES45 4@1GHz
     * OS      : Compaq Tru64 Unix 5.1b
     * Compiler: Compaq C V6.4-009 on Compaq Tru64 UNIX V5.1A (Rev. 1885)
     * To build: cc cpu.c -lmach -o cpu
     *
     */

    #include <sys/types.h>
    #include <sys/sysinfo.h>
    #include <sys/resource.h>
    #include <sys/processor.h>
    #include <machine/hal_sysinfo.h>
    #include <cpuset.h>
    #include <unistd.h>

    /* for bit mask manipulation */
    #include <limits.h>    // for size of LONG_BIT
    #define BITMASK(bit)   (1 << (bit % LONG_BIT))
    #define BITSET(a,bit)  (a |= BITMASK(bit))
    #define BITTEST(a,bit) (a & BITMASK(bit))

    int
    main (argc,argv)
      int argc;
      char *argv[];
    {
      int ncpu;                     // number of cpu in the system
      int ccpu;                     // current cpu's number
      struct cpu_info cpu_info;     // cpu state
      int cpu_ids[LONG_BIT];        // array of cpu ids
      unsigned long target;         // target cpu
      int i,j;                      // dummy for calculations

      // get the number of cpu on the system
      getsysinfo(GSI_CPUS_IN_BOX, (caddr_t) &ncpu, sizeof(ncpu), 0, 0);
      printf("Number of CPU : %d\n", ncpu);

      // on which cpu are we running
      getsysinfo(GSI_CURRENT_CPU, (caddr_t) &ccpu, sizeof(ccpu), 0, 0);
      printf("Current CPU   : %d\n", ccpu);

      // get cpu state
      getsysinfo(GSI_CPU_INFO, (caddr_t) &cpu_info, sizeof(cpu_info), 0, 0);

      // cpu clock speed
      printf("CPU Speed     : %d MHz\n", cpu_info.mhz);

      // list the available cpu ids (ncpus is the largest id+1)
      printf("Available CPUs: ");
      for (i=0; i<cpu_info.ncpus; i++)
       if (BITTEST(cpu_info.cpus_present, i))
         printf("%d ", i);

      printf("\n");

      // list only the online cpu ids
      printf("Online CPUs   : ");
      for (i=0,j=-1; i<cpu_info.ncpus; i++)
       if (BITTEST(cpu_info.cpus_running, i)) {
         printf("%d ", i);
         cpu_ids[++j]=i;
       }

      printf("\n");

      // trying changing cpu (if we have more than one cpu)
      for (i=0; i<=j; i++) {
        printf("Trying to switch cpu %d...\n", i);

        // set bitmask
        target=0;
        BITSET(target,i);

        // try to bind to cpu
        if (bind_to_cpu(getpid(),target,BIND_NO_INHERIT)) {
          printf("error binding to cpu %i\n",i);
          exit(1);
        }

        // show the current cpu
        getsysinfo(GSI_CURRENT_CPU, (caddr_t) &ccpu, sizeof(ccpu), 0, 0);
        printf("Current CPU   : %d\n", ccpu);

        sleep(2); // sleep 2 seconds
      }

      return 0; // terminated
    }