some trouble whith the use of isr_send_signal()

HI,
I think I have some trouble whith the use of isr_send_signal(), if the task is already in "active state".
Please can you tell me what happend in this case :

* Interrupt 0 each 100 ms
* some times, the fonction mesure()take more time than 100 ms :

/* my exemple*/ :
void task_1 (void)  _task_ MESURE_priority_ 1
{
char i;
while (1)
	{
	i=os_wait(K_SIG,0,0);
	if(i==3)
	        {
		os_clear_signal(EVT_1);
		Mesure();
		}
	}
}

void itext0(void) interrupt 0 using 1
{
...
isr_send_signal(EVT_1);
...
}