Test program for running task on slave_pset

[Damien Zammit]

Hi,

This program requires master branch PLUS
a one line patch I just mailed in for gnumach.

Here is a simple test program to enable
a new task to run on slave_pset processor set
containing the rest of the processors in SMP kernel.

You can compile it as a sutil in hurd/sutils:

usage must be run as root eg:

$ sudo /path/to/smp /bin/bash
# stress -c 7

Damien

 >>>>>>>>>>>>>>>>>>>>>>>>>>>>>
$ cat smp.c
/* Run a task on slave_pset
    Copyright (C) 2024 Free Software Foundation, Inc.

    This file is part of the GNU Hurd.

    The GNU Hurd is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License as
    published by the Free Software Foundation; either version 2, or (at
    your option) any later version.

    The GNU Hurd is distributed in the hope that it will be useful, but
    WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */

#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <error.h>
#include <hurd.h>
#include <version.h>
#include <mach/mach_types.h>
#include <mach/mach_host.h>

static void
smp(char * const argv[])
{
   int err;
   unsigned int pset_count;
   mach_port_t hostpriv;
   processor_set_name_array_t psets = {0};
   processor_set_t slave_pset = {0};

   if (get_privileged_ports (&hostpriv, NULL))
     error (1, 0, "Must be run as root for privileged cpu control");

   err = host_processor_sets (hostpriv, &psets, &pset_count);
   if (err)
     error (1, 0, "Cannot get list of host processor sets");

   if (pset_count < 2)
     error (1, 0, "gnumach does not have the expected processor sets, 
are you running smp kernel?");

   err = host_processor_set_priv (hostpriv, psets[1], &slave_pset);
   if (err)
     error (1, 0, "Cannot get access to slave processor set");

   err = task_assign(mach_task_self(), slave_pset, FALSE);
   if (err)
     error (1, 0, "Cannot assign task self to slave processor set");

   execve(argv[1], &argv[1], NULL);
   /* NOT REACHED */
}

int
main (int argc, char **argv)
{
   smp(argv);
   return 0;
}