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) 1992-2009, 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-- This unit may be used directly from an application program by providing 40-- an appropriate WITH, and the interface can be expected to remain stable. 41 42-- This is the Solaris (native) version of this module 43 44with System.OS_Interface; 45 46package System.Task_Info is 47 pragma Preelaborate; 48 pragma Elaborate_Body; 49 -- To ensure that a body is allowed 50 51 ----------------------------------------------------- 52 -- Binding of Tasks to LWPs and LWPs to processors -- 53 ----------------------------------------------------- 54 55 -- The Solaris implementation of the GNU Low-Level Interface (GNULLI) 56 -- implements each Ada task as a Solaris thread. The Solaris thread 57 -- library distributes threads across one or more LWPs (Light Weight 58 -- Process) that are members of the same process. Solaris distributes 59 -- processes and LWPs across the available CPUs on a given machine. The 60 -- pragma Task_Info provides the mechanism to control the distribution 61 -- of tasks to LWPs, and LWPs to processors. 62 63 -- Each thread has a number of attributes that dictate it's scheduling. 64 -- These attributes are: 65 -- 66 -- New_LWP: whether a new LWP is created for this thread. 67 -- 68 -- Bound_To_LWP: whether the thread is bound to a specific LWP 69 -- for its entire lifetime. 70 -- 71 -- CPU: the CPU number associated to the LWP 72 -- 73 74 -- The Task_Info pragma: 75 76 -- pragma Task_Info (EXPRESSION); 77 78 -- allows the specification on a task by task basis of a value of type 79 -- System.Task_Info.Task_Info_Type to be passed to a task when it is 80 -- created. The specification of this type, and the effect on the task 81 -- that is created is target dependent. 82 83 -- The Task_Info pragma appears within a task definition (compare the 84 -- definition and implementation of pragma Priority). If no such pragma 85 -- appears, then the value Unspecified_Task_Info is passed. If a pragma 86 -- is present, then it supplies an alternative value. If the argument of 87 -- the pragma is a discriminant reference, then the value can be set on 88 -- a task by task basis by supplying the appropriate discriminant value. 89 90 -- Note that this means that the type used for Task_Info_Type must be 91 -- suitable for use as a discriminant (i.e. a scalar or access type). 92 93 ----------------------- 94 -- Thread Attributes -- 95 ----------------------- 96 97 subtype CPU_Number is System.OS_Interface.processorid_t; 98 99 CPU_UNCHANGED : constant CPU_Number := System.OS_Interface.PBIND_QUERY; 100 -- Do not bind the LWP to a specific processor 101 102 ANY_CPU : constant CPU_Number := System.OS_Interface.PBIND_NONE; 103 -- Bind the LWP to any processor 104 105 Invalid_CPU_Number : exception; 106 107 type Thread_Attributes (New_LWP : Boolean) is record 108 Bound_To_LWP : Boolean := True; 109 case New_LWP is 110 when False => 111 null; 112 when True => 113 CPU : CPU_Number := CPU_UNCHANGED; 114 end case; 115 end record; 116 117 Default_Thread_Attributes : constant Thread_Attributes := (False, True); 118 119 function Unbound_Thread_Attributes 120 return Thread_Attributes; 121 122 function Bound_Thread_Attributes 123 return Thread_Attributes; 124 125 function Bound_Thread_Attributes (CPU : CPU_Number) 126 return Thread_Attributes; 127 128 type Task_Info_Type is access all Thread_Attributes; 129 130 function New_Unbound_Thread_Attributes 131 return Task_Info_Type; 132 133 function New_Bound_Thread_Attributes 134 return Task_Info_Type; 135 136 function New_Bound_Thread_Attributes (CPU : CPU_Number) 137 return Task_Info_Type; 138 139 Unspecified_Task_Info : constant Task_Info_Type := null; 140 141end System.Task_Info; 142