int main()
{
A a = get(0);
std::cout << std::endl;
// //uncomment one of the following
#define QUICK
//#undef QUICK
#ifdef QUICK
{
for (int i = 0; i < 2; ++i) {
A a = get_fast(i); // return value optimization ! (instead of using a temporary... the actual object a is used)
}
// http://www.informit.com/articles/article.aspx?p=25033&seqNum=4
}
#else
{
A a; // programmers think it's fast to just construct this once (instead of on every loop)
for (int i = 0; i < 2; ++i) {
a = get_fast(i); // in actual fact this line is incredibly slow: constructor and destructor of a temporary, as well as copy-assignment!!
}
}
#endif
return 0;
}
void scheduler()
{
unsigned int cpu_id = CPUID;
struct scheduler_info *si = &(cpu[ cpu_id ].sched);
struct thread *tr;
int idle;
int flip = 0;
uint64_t requested_time = TIMESLICE;
// We will never go back.
set_cpu_flags( cpu_flags() & ~EFLAG_NESTED_TASK );
// Now we're working.
acquire_spinlock( &(si->lock_scheduler) );
// Start timing the scheduler
stats_time_start( &(cpu[ cpu_id ].st_schedulerTime) );
assert( (cpu_flags() & EFLAG_INTERRUPT) == 0 );
ack_apic();
while (1==1)
{
// Just show the world that we're still alive.
((char*)0xB8000)[158 - cpu_id * 2] ++ ; /// \todo remove one day
// If the garbage collector has work to do, let it run.
if ( gc_has_work( cpu_id ) == 0 )
{
tr = smk_gc[ cpu_id ];
exec_thread( cpu_id, tr, TIMESLICE, 0 );
stats_time( cpu_id, &(cpu[ cpu_id ].st_systemTime) );
}
// Find out when the next timed event is.
requested_time = remove_timers( si, cpu[ cpu_id ].st_systemTime.usage );
idle = 0;
// Fast queue support
if ( flip == 0 )
{
tr = get_fast( si );
if ( tr != NULL )
{
exec_thread( cpu_id, tr, TIMESLICE, 0 );
stats_time( cpu_id, &(cpu[ cpu_id ].st_systemTime) );
// Maintain CPU time.
if ( si->sched_count != 0 ) flip = 1; // Ensure others run
continue;
}
}
flip = 0;
// Reset of fast queue
// If there's nothing to do, do idle.
if ( si->sched_count == 0 )
{
if ( gc_has_work( cpu_id ) == 0 ) continue; // Al-e-oop!
tr = smk_idle[ cpu_id ];
idle = 1; // Safe to wake up when required.
}
else
{
tr = si->sched_queue[ si->position ].tr;
si->position = (si->position + 1) % si->sched_count;
requested_time = TIMESLICE;
idle = 0; // Don't interrupt until timeslice is over
}
// And run the selected thread.
exec_thread( cpu_id, tr, requested_time, idle );
stats_time( cpu_id, &(cpu[ cpu_id ].st_systemTime) );
// Maintain CPU time.
//
// If the previous thread requested a state change, honour it.
remove_last( si );
}
}