Цитат: Hello,
I am talking about Intel Pentium 4 (2.8GHz, 478-pin, 533MHz FSB, 512KB L2, 0.13um)and 82801DB ICH4 (this is part of 845GE chipset). We are using DOS to test real-time performance of Pentium 4 motherboard. Expected response time is few microseconds. System is in PIC mode (APIC disabled), all interrupts on master and slave PIC disabled, all interrupts on CPU disabled (asm("cli");), digital scope connected to D7 pin on the parallel port, we are using gcc compiler to do this:
...
while(1)
{
outportb(0x378, 0x80);
outportb(0x378, 0x00);
}
...
Digital scope is set to trigger when pulse width is >20us.
When we start program, after few minutes scope will trigger, showing about 250us stall on CPU. This is happening every few minutes, sometimes in less than one minute and it is not periodic. |