old-autovect-branch/gcc/ada/s-tasinf-irix-athread.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                     S Y S T E M . T A S K _ I N F O                      --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2005 Free Software Foundation, Inc.          --
  10 --                                                                          --
  11 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  14 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  19 -- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --
  20 -- Boston, MA 02110-1301, USA.                                              --
  21 --                                                                          --
  22 -- As a special exception,  if other files  instantiate  generics from this --
  23 -- unit, or you link  this unit with other files  to produce an executable, --
  24 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  25 -- covered  by the  GNU  General  Public  License.  This exception does not --
  26 -- however invalidate  any other reasons why  the executable file  might be --
  27 -- covered by the  GNU Public License.                                      --
  28 --                                                                          --
  29 -- GNAT was originally developed  by the GNAT team at  New York University. --
  30 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 --  This package contains the definitions and routines associated with the
  35 --  implementation and use of the Task_Info pragma. It is specialized
  36 --  appropriately for targets that make use of this pragma.
  37
  38 --  Note: the compiler generates direct calls to this interface, via Rtsfind.
  39 --  Any changes to this interface may require corresponding compiler changes.
  40
  41 --  This unit may be used directly from an application program by providing
  42 --  an appropriate WITH, and the interface can be expected to remain stable.
  43
  44 --  This is the SGI (libathread) specific version of this module
  45
  46 with System.OS_Interface;
  47
  48 package System.Task_Info is
  49    pragma Preelaborate;
  50    pragma Elaborate_Body;
  51    --  To ensure that a body is allowed
  52
  53    ---------------------------------------------------------
  54    -- Binding of Tasks to sprocs and sprocs to processors --
  55    ---------------------------------------------------------
  56
  57    --  The SGI implementation of the GNU Low-Level Interface (GNULLI)
  58    --  implements each Ada task as a Posix thread (Pthread). The SGI
  59    --  Pthread library distributes threads across one or more processes
  60    --  that are members of a common share group. Irix distributes
  61    --  processes across the available CPUs on a given machine. The
  62    --  pragma Task_Info provides the mechanism to control the distribution
  63    --  of tasks to sprocs, and sprocs to processors.
  64
  65    --  Each thread has a number of attributes that dictate it's scheduling.
  66    --  These attributes are:
  67
  68    --      Bound_To_Sproc:  whether the thread is bound to a specific sproc
  69    --                       for its entire lifetime.
  70
  71    --      Timeslice:       Amount of time that a thread is allowed to execute
  72    --                       before the system yeilds control to another thread
  73    --                       of equal priority.
  74
  75    --      Resource_Vector: A bitmask used to control the binding of threads
  76    --                       to sprocs.
  77    --
  78
  79    --  Each share group process (sproc)
  80
  81    --  The Task_Info pragma:
  82
  83    --    pragma Task_Info (EXPRESSION);
  84
  85    --  allows the specification on a task by task basis of a value of type
  86    --  System.Task_Info.Task_Info_Type to be passed to a task when it is
  87    --  created. The specification of this type, and the effect on the task
  88    --  that is created is target dependent.
  89
  90    --  The Task_Info pragma appears within a task definition (compare the
  91    --  definition and implementation of pragma Priority). If no such pragma
  92    --  appears, then the value Task_Info_Unspecified is passed. If a pragma
  93    --  is present, then it supplies an alternative value. If the argument of
  94    --  the pragma is a discriminant reference, then the value can be set on
  95    --  a task by task basis by supplying the appropriate discriminant value.
  96
  97    --  Note that this means that the type used for Task_Info_Type must be
  98    --  suitable for use as a discriminant (i.e. a scalar or access type).
  99
 100    ----------------------
 101    -- Resource Vectors --
 102    ----------------------
 103
 104    --  <discussion>
 105
 106    type Resource_Vector_T is array (0 .. 31) of Boolean;
 107    pragma Pack (Resource_Vector_T);
 108
 109    NO_RESOURCES : constant Resource_Vector_T := (others => False);
 110
 111    generic
 112       type Resource_T is (<>);
 113       --  Discrete type up to 32 entries
 114
 115    package Resource_Vector_Functions is
 116       function "+"
 117         (R : Resource_T) return Resource_Vector_T;
 118
 119       function "+"
 120         (R1 : Resource_T;
 121          R2 : Resource_T) return Resource_Vector_T;
 122
 123       function "+"
 124         (R : Resource_T;
 125          S : Resource_Vector_T) return Resource_Vector_T;
 126
 127       function "+"
 128         (S : Resource_Vector_T;
 129          R : Resource_T) return Resource_Vector_T;
 130
 131       function "+"
 132         (S1 : Resource_Vector_T;
 133          S2 : Resource_Vector_T) return Resource_Vector_T;
 134
 135       function "-"
 136         (S : Resource_Vector_T;
 137          R : Resource_T) return Resource_Vector_T;
 138    end Resource_Vector_Functions;
 139
 140    ----------------------
 141    -- Sproc Attributes --
 142    ----------------------
 143
 144    subtype sproc_t is System.OS_Interface.sproc_t;
 145
 146    subtype CPU_Number is Integer range -1 .. Integer'Last;
 147
 148    ANY_CPU : constant CPU_Number := CPU_Number'First;
 149
 150    type Non_Degrading_Priority is range 0 .. 255;
 151    --  Specification of IRIX Non Degrading Priorities
 152    --
 153    --  WARNING: IRIX priorities have the reverse meaning of Ada priorities.
 154    --           The lower the priority value, the greater the greater the
 155    --           scheduling preference.
 156    --
 157    --  See the schedctl(2) man page for a complete discussion of non-degrading
 158    --  priorities.
 159
 160    NDPHIMAX : constant Non_Degrading_Priority := 30;
 161    NDPHIMIN : constant Non_Degrading_Priority := 39;
 162    --  These priorities are higher than ALL normal user process priorities
 163
 164    subtype NDP_High is Non_Degrading_Priority range NDPHIMAX .. NDPHIMIN;
 165
 166    NDPNORMMAX : constant Non_Degrading_Priority := 40;
 167    NDPNORMMIN : constant Non_Degrading_Priority := 127;
 168    --  These priorities overlap normal user process priorities
 169
 170    subtype NDP_Norm is Non_Degrading_Priority range NDPNORMMAX .. NDPNORMMIN;
 171
 172    NDPLOMAX : constant Non_Degrading_Priority := 128;
 173    NDPLOMIN : constant Non_Degrading_Priority := 254;
 174    --  These priorities are below ALL normal user process priorities
 175
 176    NDP_NONE   : constant Non_Degrading_Priority := 255;
 177
 178    subtype NDP_LOW is Non_Degrading_Priority range NDPLOMAX .. NDPLOMIN;
 179
 180    type Page_Locking is
 181       (NOLOCK,     --  Do not lock pages in memory
 182        PROCLOCK,   --  Lock text and data segments into memory (process lock)
 183        TXTLOCK,    --  Lock text segment into memory (text lock)
 184        DATLOCK     --  Lock data segment into memory (data lock)
 185       );
 186
 187    type Sproc_Attributes is record
 188       Sproc_Resources : Resource_Vector_T      := NO_RESOURCES;
 189       CPU             : CPU_Number             := ANY_CPU;
 190       Resident        : Page_Locking           := NOLOCK;
 191       NDPRI           : Non_Degrading_Priority := NDP_NONE;
 192 --  ??? why is that commented out, should it be removed ?
 193 --       Sproc_Slice     : Duration               := 0.0;
 194 --       Deadline_Period : Duration               := 0.0;
 195 --       Deadline_Alloc  : Duration               := 0.0;
 196    end record;
 197
 198    Default_Sproc_Attributes : constant Sproc_Attributes :=
 199       (NO_RESOURCES, ANY_CPU, NOLOCK, NDP_NONE);
 200
 201    function New_Sproc (Attr : Sproc_Attributes) return sproc_t;
 202    function New_Sproc
 203      (Sproc_Resources : Resource_Vector_T      := NO_RESOURCES;
 204       CPU             : CPU_Number             := ANY_CPU;
 205       Resident        : Page_Locking           := NOLOCK;
 206       NDPRI           : Non_Degrading_Priority := NDP_NONE) return sproc_t;
 207    --  Allocates a sproc_t control structure and creates corresponding sproc
 208
 209    Invalid_CPU_Number : exception;
 210    Permission_Error   : exception;
 211    Sproc_Create_Error : exception;
 212
 213    -----------------------
 214    -- Thread Attributes --
 215    -----------------------
 216
 217    type Thread_Attributes (Bound_To_Sproc : Boolean) is record
 218       Thread_Resources : Resource_Vector_T := NO_RESOURCES;
 219
 220       Thread_Timeslice : Duration          := 0.0;
 221
 222       case Bound_To_Sproc is
 223          when False =>
 224             null;
 225          when True   =>
 226             Sproc : sproc_t;
 227       end case;
 228    end record;
 229
 230    Default_Thread_Attributes : constant Thread_Attributes :=
 231      (False, NO_RESOURCES, 0.0);
 232
 233    function Unbound_Thread_Attributes
 234      (Thread_Resources : Resource_Vector_T := NO_RESOURCES;
 235       Thread_Timeslice : Duration          := 0.0) return Thread_Attributes;
 236
 237    function Bound_Thread_Attributes
 238      (Thread_Resources : Resource_Vector_T := NO_RESOURCES;
 239       Thread_Timeslice : Duration          := 0.0;
 240       Sproc            : sproc_t) return Thread_Attributes;
 241
 242    function Bound_Thread_Attributes
 243      (Thread_Resources : Resource_Vector_T      := NO_RESOURCES;
 244       Thread_Timeslice : Duration               := 0.0;
 245       Sproc_Resources  : Resource_Vector_T      := NO_RESOURCES;
 246       CPU              : CPU_Number             := ANY_CPU;
 247       Resident         : Page_Locking           := NOLOCK;
 248       NDPRI            : Non_Degrading_Priority := NDP_NONE)
 249       return Thread_Attributes;
 250
 251    type Task_Info_Type is access all Thread_Attributes;
 252
 253    function New_Unbound_Thread_Attributes
 254      (Thread_Resources : Resource_Vector_T := NO_RESOURCES;
 255       Thread_Timeslice : Duration          := 0.0)
 256       return Task_Info_Type;
 257
 258    function New_Bound_Thread_Attributes
 259      (Thread_Resources : Resource_Vector_T := NO_RESOURCES;
 260       Thread_Timeslice : Duration          := 0.0;
 261       Sproc            : sproc_t) return Task_Info_Type;
 262
 263    function New_Bound_Thread_Attributes
 264      (Thread_Resources : Resource_Vector_T      := NO_RESOURCES;
 265       Thread_Timeslice : Duration               := 0.0;
 266       Sproc_Resources  : Resource_Vector_T      := NO_RESOURCES;
 267       CPU              : CPU_Number             := ANY_CPU;
 268       Resident         : Page_Locking           := NOLOCK;
 269       NDPRI            : Non_Degrading_Priority := NDP_NONE)
 270       return Task_Info_Type;
 271
 272    Unspecified_Task_Info : constant Task_Info_Type := null;
 273
 274 end System.Task_Info;