problem with gpiote interrupt

Question

I ´m testing gpiote interrupt, i´m work with nrf51-dk, softdevice S110 and sdk 9.0.0. 
 I have a pin that receives a signal 0 all time, and it changes to 1 when I have to do some tasks, I declared pin as input, in init I say the configuracion of the interrupt, priority. 
 The thing is that I have a function that it makes a large amount of calculations, if I comment this fuction, i have 500 interrupts that are i have to receive but if i discomment function, the interrupt is about 250 and i don´t know why because I set priority to highest. 
 handler 
 void controlador_evento_interrupcion(nrf_drv_gpiote_pin_t pin, nrf_gpiote_polarity_t action){
	lecturas++;
}
 
 init 
 void interrupt_pin_inicio(){
	uint32_t err_code;
	nrf_drv_gpiote_in_config_t configuracion;
	configuracion.is_watcher = false;
	configuracion.hi_accuracy = true;
	configuracion.pull = NRF_GPIO_PIN_PULLUP;
	configuracion.sense = NRF_GPIOTE_POLARITY_LOTOHI;
	
	NVIC_EnableIRQ(GPIOTE_IRQn);
	NVIC_SetPriority(GPIOTE_IRQn, 1);

	err_code = nrf_drv_gpiote_init();	
	//printf("Error: %zu ", err_code);

	err_code = nrf_drv_gpiote_in_init(pin_interrupcion_lectura, &configuracion, controlador_evento_interrupcion);
	//printf("Error: %zu ", err_code);

	nrf_drv_gpiote_in_event_enable(pin_interrupcion_lectura , true);
	//printf("Error: %zu ", err_code);
}
 
 main declaration 
 nrf_gpio_cfg_input(pin_interrupcion_lectura, NRF_GPIO_PIN_PULLUP);
 
 Thank you.