unix/SysThread.cpp

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/******************************************************************************/
/* REXX Kernel                                              SysThread.cpp     */
/*                                                                            */
/* Unix implementation of the SysThread class.                                */
/*                                                                            */
/******************************************************************************/
 
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
 
#include "SysThread.hpp"
#include <stdio.h>
#include <unistd.h>
 
// attach an activity to an existing thread
void SysThread::attachThread()
{
    // initialize the thread basics
    _threadID = pthread_self();
    attached = true;      // we didn't create this one
}
 
 
void SysThread::setPriority(int priority)
{
    int schedpolicy;
    struct sched_param schedparam;
 
    pthread_getschedparam(_threadID,  &schedpolicy, &schedparam);
 
    /* Medium_priority(=100) is used for every new thread */
    schedparam.sched_priority = priority;
    pthread_setschedparam(_threadID, schedpolicy, &schedparam);
}
 
 
void SysThread::dispatch()
{
    // default dispatch returns immediately
}
 
 
void SysThread::terminate()
{
    if (!attached && _threadID != 0)
    {
        pthread_detach(_threadID);
        _threadID = 0;
    }
}
 
 
void SysThread::startup()
{
    // this is a nop on Unix.
}
 
 
void SysThread::shutdown()
{
    // this is a nop on Unix.
}
 
 
void SysThread::yield()
{
    sched_yield();
}
 
 
bool SysThread::equals(SysThread &other)
{
    return pthread_equal(_threadID, other._threadID);
}
 
 
static void * call_thread_function(void *argument)
{
    ((SysThread *)argument)->dispatch();
    return NULL;
}
 
 
// create a new thread and attach to an activity
void SysThread::createThread(void)
{
    pthread_attr_t  newThreadAttr;
    int schedpolicy, maxpri, minpri;
    struct sched_param schedparam;
 
    // Create an attr block for Thread.
    pthread_attr_init(&newThreadAttr);
#if defined(LINUX) ||  defined(OPSYS_SUN) || defined(AIX)
    /* scheduling on two threads controlled by the result method of the */
    /* message object do not work properly without an enhanced priority */
    pthread_getschedparam(pthread_self(), &schedpolicy, &schedparam);
 
#if defined(AIX)
  // Starting with AIX 5.3 the priority for a thread created by
  // a non root user can not be higher then 59. The priority
  // of a user prog should not be higher then 59 (IBM AIX development).
  schedparam.sched_priority = 59;
#else
#   ifdef _POSIX_PRIORITY_SCHEDULING
        maxpri = sched_get_priority_max(schedpolicy);
        minpri = sched_get_priority_min(schedpolicy);
        schedparam.sched_priority = (minpri + maxpri) / 2;
#   endif
#endif
 
#if defined(OPSYS_SUN)
    /* PTHREAD_EXPLICIT_SCHED ==> use scheduling attributes of the new object */
    pthread_attr_setinheritsched(&newThreadAttr, PTHREAD_EXPLICIT_SCHED);
 
    /* Performance measurements show massive performance improvements > 50 % */
    /* using Round Robin scheduling instead of FIFO scheduling               */
    pthread_attr_setschedpolicy(&newThreadAttr, SCHED_RR);
#endif
 
#if defined(AIX)
    /* PTHREAD_EXPLICIT_SCHED ==> use scheduling attributes of the new object */
    pthread_attr_setinheritsched(&newThreadAttr, PTHREAD_EXPLICIT_SCHED);
 
    /* Each thread has an initial priority that is dynamically modified by   */
    /* the scheduler, according to the thread's activity; thread execution   */
    /* is time-sliced. On other systems, this scheduling policy may be       */
    /* different.                                                            */
    pthread_attr_setschedpolicy(&newThreadAttr, SCHED_OTHER);
#endif
 
    pthread_attr_setschedparam(&newThreadAttr, &schedparam);
#endif
 
    // Set the stack size.
    pthread_attr_setstacksize(&newThreadAttr, THREAD_STACK_SIZE);
 
    // Now create the thread
    int rc = pthread_create(&_threadID, &newThreadAttr, call_thread_function, (void *)this);
    if (rc != 0)
    {
        _threadID = 0;
        fprintf(stderr," *** ERROR: At SysThread(), createThread - RC = %d !\n", rc);
    }
    pthread_attr_destroy(&newThreadAttr);
    attached = false;           // we own this thread
    return;
}