ATMEGA328P power down mode not working as expected

#include <avr/io.h>
#define F_CPU 1000000UL
#include <util/delay.h>
#include <avr/interrupt.h>
#include <avr/sleep.h>
#include <avr/wdt.h>
#include "uart.h"

void deepsleep(void);
void extint_enable(void);

ISR(INT0_vect)
{
}

//main routine
void main(void)
{
		DDRB |= 1<<PB0;
		extint_enable();
		sei();
		deep_sleep();
                 //after wakeup blink led
		while(1) {
			PORTB ^= 1<<PB0;
			_delay_ms(1000);
		}

}

void deep_sleep(void) {
		set_sleep_mode(SLEEP_MODE_PWR_DOWN);
		sleep_mode();
}

void extint_enable(void) {
   	 	EICRA |= (1<<ISC01)|(1<<ISC00);
      	    EIMSK |= 1<<INT0;
}

#include <avr/power.h>

// Example
power_adc_disable() 
power_spi_disable()
power_timer0_disable()
power_timer1_disable()
power_twi_disable()

#include<avr/io.h>
#include<avr/interrupt.h>
#include<stdlib.h>
[COLOR="#FF0000"]#include<avr/power.h>[/COLOR]

#define DATABUFSIZE     42
#define NUMBER_OFSET    34

char demoBuff[DATABUFSIZE] = {'M','o','r','e',' ','o','o','m','f',' ','t','o',' ','y','o','u','r',' ','a','m','p','s',',',' ','p','i','c','o','P','o','w','e','r','!',0,0,0,0,  0,'\r','\n'};
uint16_t iteration=1;

void init_adc()
{
    ADMUX = (1<<MUX3);   //Set mux to internal temp sens. 
    ADCSRA = (1<<ADEN);  //ADC enable 
}

void init_timer2()
{
    TCCR2B = (1<<CS20) | (1<<CS22);     //Clock prescaler set to 5, overflow each sec
    TIMSK2 = (1<<TOIE2);                //Enable timer2 overflow interrupt
    ASSR = (1<<AS2);                    //Enable async operation
}

void init_uart()
{
    UCSR0A = (1<<U2X0);                 // Enable U2Xn to get a baud rate with less error margin
	UCSR0B = (1<<TXEN0);	            // Transmitter enable
	UCSR0C = (1<<UCSZ00) | (1<<UCSZ01); // Asynchronous USART | No parity | 1 stopbit | CH size 8-bit
	UBRR0 = 0x0C;	                    // 19200 Baudrate@8Mhz
}

void enable_pullups()
{
    PORTB = 0xFF;   // Enables internal pull-ups on the IO pins, direction bits are by default set to 0 (input)
    PORTC = 0xFF;   // The UART tx pin will still work
    PORTD = 0xFF;
}

void enable_prr()
{
[COLOR="#FF0000"]    power_spi_disable();
    power_timer0_disable();
    power_timer1_disable();
    power_twi_disable();[/COLOR]
}

void cal_clock()
{
    OSCCAL = 0x66;  // Calibrate oscillator to 8MHz
}

int main()
{
    int count=0;

    cal_clock();
    clock_prescale_set(clock_div_4);    // Prescale systemclock to 2 MHz

    enable_pullups();
    enable_prr();
  
    init_uart();
    init_timer2();
    init_adc();

    while(1)
    {
        ADMUX |= (1<<REFS1) | (1<<REFS0); // Enable internal 1.1V ref. 
        ADCSRA |= (1<< ADSC);             // Start conversion 
        while(!(ADCSRA & (1<<ADIF)));     // Wait for ready flag
        ADMUX &= (1<<MUX3);               // Disable internal 1.1V ref.

        utoa(iteration, &demoBuff[NUMBER_OFSET], 10);       // Generate desimal number string from itt

       	__asm__ volatile (                // Simulate 1000 cycles of processing
            "ldi r24, 25" "\n\t"          // Load 25 into register 24
    	    "1: sbiw r24,1" "\n\t"        // Subtract 1 for each iteration
            "brne 1b"                     // Branch if not equal (Z = 0), the loop takes 4 cycles
	    );

        for(count=0;count<DATABUFSIZE;++count)
        {
            while(!(UCSR0A & (1<<UDRE0)));  // Wait for the last byte to be shifted out of the data register in the UART module

            UDR0 = demoBuff[count];
        }


        while(!(TIFR2 & (1<<TOV2)));             // Wait for the timer to count a second 
        TIFR2 = (1<<TOV2);                       // Reset timer/counter 2 interrupt flag

        iteration++;                              // Increase the itterator counter
    }

    return 0;
}