unix/SysActivity.cpp

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/******************************************************************************/
/* REXX Kernel                                            SysActivity.hpp     */
/*                                                                            */
/* System support for Thread operations                                       */
/*                                                                            */
/******************************************************************************/
 
#include "RexxCore.h"
#include "ActivityManager.hpp"
#include <errno.h>
 
#define THREAD_PRIORITY 100
 
#include "RexxCore.h"
#include "SysActivity.hpp"
 
 
/**
 * Top launcher function for spinning off a new activity.
 *
 * @param args   The thread arguments (just the pointer to the activity).
 */
void *threadFnc(void *args)
{
    ((RexxActivity *)args)->runThread();
    return NULL;
}
 
/**
 * Close out any resources required by this thread descriptor.
 */
void SysActivity::close()
{
    threadId = 0;
}
 
/**
 * Create a new thread for an activity.
 *
 * @param activity  The activity that will run on this thread.
 * @param stackSize The desired stack size.
 */
void SysActivity::create(RexxActivity *activity, size_t stackSize)
{
    int             rc;
    pthread_attr_t  newThreadAttr;
    int schedpolicy;
    struct sched_param schedparam;
 
                               // Create an attr block for Thread.
    rc = pthread_attr_init(&newThreadAttr);
                               // Set the stack size.
 #if defined(LINUX) || defined(OPSYS_SUN) || defined(AIX)
 
 /* scheduling on two threads controlled by the result method of the message object */
 /* do not work proper without an enhanced priority                                 */
 
    pthread_getschedparam(pthread_self(), &schedpolicy, &schedparam);
    schedparam.sched_priority = 100;
 
 #if defined(OPSYS_SUN)
 /* PTHREAD_EXPLICIT_SCHED ==> use scheduling attributes of the new object    */
 
    rc = pthread_attr_setinheritsched(&newThreadAttr, PTHREAD_EXPLICIT_SCHED);
 
 /* Performance measurements show massive performance improvements > 50 %     */
 /* using Round Robin scheduling instead of FIFO scheduling                   */
    rc = pthread_attr_setschedpolicy(&newThreadAttr, SCHED_RR);
 #endif
    rc = pthread_attr_setschedparam(&newThreadAttr, &schedparam);
 
 #endif
    rc = pthread_attr_setstacksize(&newThreadAttr, stackSize);
                                               // Now create the thread
    rc = pthread_create(&threadId, &newThreadAttr, threadFnc, (void *)activity);
                               // Bumop thread count by one. Threadid
    if (rc != 0)
    {
        reportException(Error_System_service_service, "ERROR CREATING THREAD");
    }
    rc = pthread_attr_destroy(&newThreadAttr);
}
 
 
/**
 * Get the ID of the current thread.
 *
 * @return The thread identifer for the current thread.
 */
thread_id_t SysActivity::queryThreadID()
{
    return (thread_id_t)pthread_self();      /* just call the correct function */
}
 
 
/**
 * Check if this activity is getting used on the correct
 * thread.
 *
 * @return true if the current thread is the same as the one
 *         the activity was created for.
 */
bool SysActivity::validateThread()
{
    return threadId == pthread_self();
}
 
 
/**
 * Initialize the descriptor for manipulating the current
 * active thread.
 */
void SysActivity::useCurrentThread()
{
    // we need both an identifier and a handle
    threadId = pthread_self();
}
 
 
/**
 * Return the pointer to the base of the current stack.
 * This is used for checking recursion overflows.
 *
 * @param base      A local variable at the base of the stack.
 * @param stackSize
 *
 * @return The character pointer for the stack base.
 */
char *SysActivity::getStackBase(int32_t *base, size_t stackSize)
{
    return (char *)base - stackSize;
}
 
 
wholenumber_t yieldCount = 0; // Monitoring
 
void SysActivity::yield()
{
    yieldCount += 1;
    sched_yield();
}
 
 
wholenumber_t SysActivity::yieldCounter()
{
    return yieldCount;
}