How to fetch the popular post in wordpress according to views

functions.php

<?php 
/* for popular post*/
/* set the post view count*/

function wpb_set_post_views($postID) {
    $count_key = 'wpb_post_views_count';
    $count = get_post_meta($postID, $count_key, true);
    if($count==''){
        $count = 0;
        delete_post_meta($postID, $count_key);
        add_post_meta($postID, $count_key, '0');
    }else{
        $count++;
        update_post_meta($postID, $count_key, $count);
    }
}
//To keep the count accurate, lets get rid of prefetching
remove_action( 'wp_head', 'adjacent_posts_rel_link_wp_head', 10, 0);
/* get the post view count*/
function wpb_get_post_views($postID){
    $count_key = 'wpb_post_views_count';
    $count = get_post_meta($postID, $count_key, true);
    if($count==''){
        delete_post_meta($postID, $count_key);
        add_post_meta($postID, $count_key, '0');
        return "0 View";
    }
    return $count.' Views';
}
?>

sidebar.php

         <ul class="blog-list-sidebar">
          <?php 
           //set your post type
		$popularpost = new WP_Query( array( 'post_type'=>'blog', 'posts_per_page' => 5, 'meta_key' => 'wpb_post_views_count', 'orderby' => 'meta_value_num', 'order' => 'DESC'  ) );
		while ( $popularpost->have_posts() ) : $popularpost->the_post(); 
		$url = wp_get_attachment_url( get_post_thumbnail_id($post->ID) );
		?>
              <li>
                <div class="post-thumb"> <a href="<?php the_permalink();?>"><img src="<?php echo $url ;?>" alt="Blog"></a> </div>
                <div class="post-info">
                  <h5 class="entry_title"><a href="<?php the_permalink();?>"><?php the_title();?></a></h5>
                  <div class="post-meta"> <span class="date"><i class="pe-7s-date"></i> 2014-08-05</span> <span class="comment-count"> <i class="pe-7s-comment-o"></i> 3 </span> </div>
                </div>
              </li>
              <?php endwhile; ?>
          </ul>

single.php

<?php 
if ( have_posts() ) : 
while ( have_posts() ) : the_post(); 
$url = wp_get_attachment_url( get_post_thumbnail_id($post->ID) );
wpb_set_post_views($post->ID);//this function has been define in functions.php
echo wpb_get_post_views($post->ID);?>) //this function shows the total no of views for the post.
?>
//some stufs

<?php endwhile;endif; ?>