In the following code, I need to optimize it for the fastest performance. I'm not asking anyone to do it for me, I'm asking if someone can look through the code, and let me know where I can get the best speed up by example loop unrolling a for loop or something like that. I've gone through it, and I just can not see what I should do to improve the speed.

```
/********************************************************
* Kernels to be optimized for the CS:APP Performance Lab
********************************************************/
#include <stdio.h>
#include <stdlib.h>
#include "defs.h"
/*
* Please fill in the following team struct
*/
team_t team = {
"flankerboy", /* Team name */
"", /* First member full name */
"", /* First member email address */
"", /* Second member full name (leave blank if none) */
"" /* Second member email addr (leave blank if none) */
};
/***************
* ROTATE KERNEL
***************/
/******************************************************
* Your different versions of the rotate kernel go here
******************************************************/
/*
* naive_rotate - The naive baseline version of rotate
*/
char naive_rotate_descr[] = "naive_rotate: Naive baseline implementation";
void naive_rotate(int dim, pixel *src, pixel *dst)
{
int i, j;
for (i = 0; i < dim; ++i)
for (j = 0; j < dim; ++j)
dst[RIDX(dim-1-j, i, dim)] = src[RIDX(i, j, dim)];
}
/*
* rotate - Your current working version of rotate
* IMPORTANT: This is the version you will be graded on
*/
char rotate_descr[] = "rotate: Current working version";
void rotate(int dim, pixel *src, pixel *dst)
{
naive_rotate(dim, src, dst);
}
/*********************************************************************
* register_rotate_functions - Register all of your different versions
* of the rotate kernel with the driver by calling the
* add_rotate_function() for each test function. When you run the
* driver program, it will test and report the performance of each
* registered test function.
*********************************************************************/
void register_rotate_functions()
{
add_rotate_function(&naive_rotate, naive_rotate_descr);
add_rotate_function(&rotate, rotate_descr);
/* ... Register additional test functions here */
}
/***************
* SMOOTH KERNEL
**************/
/***************************************************************
* Various typedefs and helper functions for the smooth function
* You may modify these any way you like.
**************************************************************/
/* A struct used to compute averaged pixel value */
typedef struct {
int red;
int green;
int blue;
int num;
} pixel_sum;
/* Compute min and max of two integers, respectively */
static int min(int a, int b) { return (a < b ? a : b); }
static int max(int a, int b) { return (a > b ? a : b); }
/*
* initialize_pixel_sum - Initializes all fields of sum to 0
*/
static void initialize_pixel_sum(pixel_sum *sum)
{
sum->red = sum->green = sum->blue = 0;
sum->num = 0;
return;
}
/*
* accumulate_sum - Accumulates field values of p in corresponding
* fields of sum
*/
static void accumulate_sum(pixel_sum *sum, pixel p)
{
sum->red += (int) p.red;
sum->green += (int) p.green;
sum->blue += (int) p.blue;
sum->num++;
return;
}
/*
* assign_sum_to_pixel - Computes averaged pixel value in current_pixel
*/
static void assign_sum_to_pixel(pixel *current_pixel, pixel_sum sum)
{
current_pixel->red = (unsigned short) (sum.red/sum.num);
current_pixel->green = (unsigned short) (sum.green/sum.num);
current_pixel->blue = (unsigned short) (sum.blue/sum.num);
return;
}
/*
* avg - Returns averaged pixel value at (i,j)
*/
static pixel avg(int dim, int i, int j, pixel *src)
{
int ii, jj;
pixel_sum sum;
pixel current_pixel;
initialize_pixel_sum(&sum);
for(ii = max(i-1, 0); ii <= min(i+1, dim-1); ++ii)
for(jj = max(j-1, 0); jj <= min(j+1, dim-1); ++jj)
accumulate_sum(&sum, src[RIDX(ii, jj, dim)]);
assign_sum_to_pixel(¤t_pixel, sum);
return current_pixel;
}
/******************************************************
* Your different versions of the smooth kernel go here
******************************************************/
/*
* naive_smooth - The naive baseline version of smooth
*/
char naive_smooth_descr[] = "naive_smooth: Naive baseline implementation";
void naive_smooth(int dim, pixel *src, pixel *dst)
{
int i, j;
for (i = 0; i < dim; ++i)
for (j = 0; j < dim; ++j)
dst[RIDX(i, j, dim)] = avg(dim, i, j, src);
}
/*
* smooth - Your current working version of smooth.
* IMPORTANT: This is the version you will be graded on
*/
char smooth_descr[] = "smooth: Current working version";
void smooth(int dim, pixel *src, pixel *dst)
{
naive_smooth(dim, src, dst);
}
/*********************************************************************
* register_smooth_functions - Register all of your different versions
* of the smooth kernel with the driver by calling the
* add_smooth_function() for each test function. When you run the
* driver program, it will test and report the performance of each
* registered test function.
*********************************************************************/
void register_smooth_functions() {
add_smooth_function(&smooth, smooth_descr);
add_smooth_function(&naive_smooth, naive_smooth_descr);
/* ... Register additional test functions here */
}
```