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) 1992-2019, 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 3,  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.                                     --
17--                                                                          --
18-- As a special exception under Section 7 of GPL version 3, you are granted --
19-- additional permissions described in the GCC Runtime Library Exception,   --
20-- version 3.1, as published by the Free Software Foundation.               --
21--                                                                          --
22-- You should have received a copy of the GNU General Public License and    --
23-- a copy of the GCC Runtime Library Exception along with this program;     --
24-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
25-- <http://www.gnu.org/licenses/>.                                          --
26--                                                                          --
27-- GNAT was originally developed  by the GNAT team at  New York University. --
28-- Extensive contributions were provided by Ada Core Technologies Inc.      --
29--                                                                          --
30------------------------------------------------------------------------------
31
32--  This package contains the definitions and routines associated with the
33--  implementation and use of the Task_Info pragma. It is specialized
34--  appropriately for targets that make use of this pragma.
35
36--  Note: the compiler generates direct calls to this interface, via Rtsfind.
37--  Any changes to this interface may require corresponding compiler changes.
38
39--  The functionality in this unit is now provided by the predefined package
40--  System.Multiprocessors and the CPU aspect. This package is obsolescent.
41
42--  This is the Solaris (native) version of this module
43
44with System.OS_Interface;
45
46package System.Task_Info is
47   pragma Obsolescent (Task_Info, "use System.Multiprocessors and CPU aspect");
48   pragma Preelaborate;
49   pragma Elaborate_Body;
50   --  To ensure that a body is allowed
51
52   -----------------------------------------------------
53   -- Binding of Tasks to LWPs and LWPs to processors --
54   -----------------------------------------------------
55
56   --  The Solaris implementation of the GNU Low-Level Interface (GNULLI)
57   --  implements each Ada task as a Solaris thread.  The Solaris thread
58   --  library distributes threads across one or more LWPs (Light Weight
59   --  Process) that are members of the same process. Solaris distributes
60   --  processes and LWPs across the available CPUs on a given machine. The
61   --  pragma Task_Info provides the mechanism to control the distribution
62   --  of tasks to LWPs, and LWPs to processors.
63
64   --  Each thread has a number of attributes that dictate it's scheduling.
65   --  These attributes are:
66   --
67   --      New_LWP:       whether a new LWP is created for this thread.
68   --
69   --      Bound_To_LWP:  whether the thread is bound to a specific LWP
70   --                     for its entire lifetime.
71   --
72   --      CPU:           the CPU number associated to the LWP
73   --
74
75   --  The Task_Info pragma:
76
77   --    pragma Task_Info (EXPRESSION);
78
79   --  allows the specification on a task by task basis of a value of type
80   --  System.Task_Info.Task_Info_Type to be passed to a task when it is
81   --  created. The specification of this type, and the effect on the task
82   --  that is created is target dependent.
83
84   --  The Task_Info pragma appears within a task definition (compare the
85   --  definition and implementation of pragma Priority). If no such pragma
86   --  appears, then the value Unspecified_Task_Info is passed. If a pragma
87   --  is present, then it supplies an alternative value. If the argument of
88   --  the pragma is a discriminant reference, then the value can be set on
89   --  a task by task basis by supplying the appropriate discriminant value.
90
91   --  Note that this means that the type used for Task_Info_Type must be
92   --  suitable for use as a discriminant (i.e. a scalar or access type).
93
94   -----------------------
95   -- Thread Attributes --
96   -----------------------
97
98   subtype CPU_Number is System.OS_Interface.processorid_t;
99
100   CPU_UNCHANGED : constant CPU_Number := System.OS_Interface.PBIND_QUERY;
101   --  Do not bind the LWP to a specific processor
102
103   ANY_CPU       : constant CPU_Number := System.OS_Interface.PBIND_NONE;
104   --  Bind the LWP to any processor
105
106   Invalid_CPU_Number : exception;
107
108   type Thread_Attributes (New_LWP : Boolean) is record
109      Bound_To_LWP     : Boolean    := True;
110      case New_LWP is
111         when False =>
112            null;
113         when True =>
114            CPU        : CPU_Number := CPU_UNCHANGED;
115      end case;
116   end record;
117
118   Default_Thread_Attributes : constant Thread_Attributes := (False, True);
119
120   function Unbound_Thread_Attributes
121      return Thread_Attributes;
122
123   function Bound_Thread_Attributes
124      return Thread_Attributes;
125
126   function Bound_Thread_Attributes (CPU : CPU_Number)
127      return Thread_Attributes;
128
129   type Task_Info_Type is access all Thread_Attributes;
130
131   function New_Unbound_Thread_Attributes
132      return Task_Info_Type;
133
134   function New_Bound_Thread_Attributes
135      return Task_Info_Type;
136
137   function New_Bound_Thread_Attributes (CPU : CPU_Number)
138      return Task_Info_Type;
139
140   Unspecified_Task_Info : constant Task_Info_Type := null;
141
142   function Number_Of_Processors return Positive;
143   --  Returns the number of processors on the running host
144
145end System.Task_Info;
146