diff packages/kernel/current/include/lottery.hxx @ 0:3111d98ba7b3 ecos-v1_1-release

Initial commit of eCos version 1.1
author jlarmour
date Tue, 11 May 1999 11:16:07 +0000
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children 443894e2e912
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+++ b/packages/kernel/current/include/lottery.hxx
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+#ifndef CYGONCE_KERNEL_LOTTERY_HXX
+#define CYGONCE_KERNEL_LOTTERY_HXX
+
+//==========================================================================
+//
+//	lottery.hxx
+//
+//	Lottery scheduler class declarations
+//
+//==========================================================================
+//####COPYRIGHTBEGIN####
+//
+// -------------------------------------------
+// The contents of this file are subject to the Cygnus eCos Public License
+// Version 1.0 (the "License"); you may not use this file except in
+// compliance with the License.  You may obtain a copy of the License at
+// http://sourceware.cygnus.com/ecos
+// 
+// Software distributed under the License is distributed on an "AS IS"
+// basis, WITHOUT WARRANTY OF ANY KIND, either express or implied.  See the
+// License for the specific language governing rights and limitations under
+// the License.
+// 
+// The Original Code is eCos - Embedded Cygnus Operating System, released
+// September 30, 1998.
+// 
+// The Initial Developer of the Original Code is Cygnus.  Portions created
+// by Cygnus are Copyright (C) 1998 Cygnus Solutions.  All Rights Reserved.
+// -------------------------------------------
+//
+//####COPYRIGHTEND####
+//==========================================================================
+//#####DESCRIPTIONBEGIN####
+//
+// Author(s): 	nickg
+// Contributors:	nickg
+// Date:	1997-09-10
+// Purpose:	Define lottery scheduler implementation
+// Description:	The classes defined here are used as base classes
+//              by the common classes that define schedulers and thread
+//              things. A lottery scheduler provides each thread with a
+//              share of the processor based on the number of tickets that
+//              it owns.
+// Usage:       Included according to configuration by
+//              <cyg/kernel/sched.hxx>
+//
+//####DESCRIPTIONEND####
+//
+//==========================================================================
+
+#include <cyg/kernel/ktypes.h>
+
+// -------------------------------------------------------------------------
+// Customize the scheduler
+
+#define CYGIMP_THREAD_PRIORITY  1       // Threads have changable priorities
+
+#define CYG_THREAD_MIN_PRIORITY 1
+#define CYG_THREAD_MAX_PRIORITY 0x7FFFFFFF
+
+// set default scheduling info value for thread constructors.
+#define CYG_SCHED_DEFAULT_INFO  CYG_THREAD_MAX_PRIORITY
+
+#error Lottery Scheduler not yet complete, do not use!!!
+
+// -------------------------------------------------------------------------
+// Thread queue implementation.
+// This class provides the (scheduler specific) implementation of the
+// thread queue class.
+
+class Cyg_ThreadQueue_Implementation
+{
+    friend class Cyg_Scheduler_Implementation;
+    friend class Cyg_SchedThread_Implementation;
+    
+    Cyg_Thread *queue;
+
+protected:
+
+    // API used by Cyg_ThreadQueue
+
+                                        // Add thread to queue
+    void                enqueue(Cyg_Thread *thread);
+
+                                        // return first thread on queue
+    Cyg_Thread          *highpri();
+
+                                        // remove first thread on queue    
+    Cyg_Thread          *dequeue();
+
+                                        // remove specified thread from queue    
+    void                remove(Cyg_Thread *thread);
+
+                                        // test if queue is empty
+    cyg_bool            empty();
+
+    void                rotate();       // Rotate the queue
+};
+
+inline cyg_bool Cyg_ThreadQueue_Implementation::empty()
+{
+    return queue == NULL;
+}
+
+// -------------------------------------------------------------------------
+// This class contains the implementation details of the scheduler, and
+// provides a standard API for accessing it.
+
+class Cyg_Scheduler_Implementation
+    : public Cyg_Scheduler_Base
+{
+    friend class Cyg_ThreadQueue_Implementation;
+    friend class Cyg_SchedThread_Implementation;
+
+    // All runnable threads are kept on a single run queue
+    // in MRU order.
+    Cyg_ThreadQueue_Implementation     run_queue;
+
+    cyg_uint32  rand_seed;
+
+    cyg_int32   total_tickets;
+    
+protected:
+
+    Cyg_Scheduler_Implementation();     // Constructor
+    
+    // The following functions provide the scheduler implementation
+    // interface to the Cyg_Scheduler class. These are protected
+    // so that only the scheduler can call them.
+    
+    // choose a new thread
+    Cyg_Thread  *schedule();
+
+    // make thread schedulable
+    void        add_thread(Cyg_Thread *thread);
+
+    // make thread un-schedulable
+    void        rem_thread(Cyg_Thread *thread);
+
+    // register thread with scheduler
+    void        register_thread(Cyg_Thread *thread);
+
+    // deregister thread
+    void        deregister_thread(Cyg_Thread *thread);
+    
+    // Test the given priority for uniqueness
+    cyg_bool    unique( cyg_priority priority);
+
+#ifdef CYGSEM_KERNEL_SCHED_TIMESLICE
+
+    // If timeslicing is enbled, define a scheduler
+    // entry point to do timeslicing. This will be
+    // called from the RTC DSR.
+
+protected:
+    
+    static cyg_count32         timeslice_count;
+    
+public:    
+    void timeslice();
+
+    static void reset_timeslice_count();
+    
+#endif
+    
+    
+};
+
+// -------------------------------------------------------------------------
+// Cyg_Scheduler_Implementation inlines
+
+#ifdef CYGSEM_KERNEL_SCHED_TIMESLICE
+
+inline void Cyg_Scheduler_Implementation::reset_timeslice_count()
+{
+    timeslice_count = CYGNUM_KERNEL_SCHED_TIMESLICE_TICKS;
+}
+
+#endif
+
+// -------------------------------------------------------------------------
+// Scheduler thread implementation.
+// This class provides the implementation of the scheduler specific parts
+// of each thread.
+
+class Cyg_SchedThread_Implementation
+{
+    friend class Cyg_Scheduler_Implementation;
+    friend class Cyg_ThreadQueue_Implementation;
+
+    Cyg_Thread *next;                   // next thread in queue
+    Cyg_Thread *prev;                   // previous thread in queue
+        
+    void insert( Cyg_Thread *thread );  // Insert thread in front of this
+
+    void remove();                      // remove this from queue
+    
+protected:
+
+    cyg_priority        priority;       // current thread priority == tickets held
+
+    cyg_priority        compensation_tickets;   // sleep compensation
+    
+    Cyg_SchedThread_Implementation(CYG_ADDRWORD sched_info);
+
+    void yield();                       // Yield CPU to next thread
+
+};
+
+// -------------------------------------------------------------------------
+#endif // ifndef CYGONCE_KERNEL_LOTTERY_HXX
+// EOF lottery.hxx