Channels ▼
RSS

The Boehm Collector for C and C++


Listing 1: Creates a large linked list and destroys it

Listing 1: Creates a large linked list and destroys it

/*
 * $Id: listing1.c,v 1.4 2002/06/04 12:53:04 gene Exp gene $
 * Performance comparison
 */

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <gc.h>

struct node
{
  struct node *next;
  int dummy_payload;
};

static const double loop_seconds = 17.0;
static const int list_length = (2 * 1024 * 1024) / sizeof (struct node);

/* Make a new list of 'length' nodes.  'alloc' should be
 * &malloc or &GC_malloc. */
static struct node *
MakeList (int length, void *(*alloc) (size_t))
{
  struct node *lst = NULL, *tmp;

  while (length-- > 0) {
    tmp = (struct node *) (*alloc) (sizeof *tmp);
    tmp->next = lst;
    lst = tmp;
  }
  return lst;
}

/* Explicitly free the nodes in the list. */
static void
FreeList (struct node *lst)
{
  while (lst != NULL) {
    struct node *tmp = lst->next;
    free (lst);
    lst = tmp;
  }
}

/* Pretend to free the list, but do nothing.  Rely on garbage
 * collection to free the list. */
static void
IgnoreList (struct node *lst)
{
}

static unsigned long
Loop (void *(*alloc) (size_t), void (*free_list) (struct node *))
{
  unsigned long count = 0;
  time_t start, now;

  time (&start);
  do {
    ++count;
    (*free_list) (MakeList (list_length, alloc));
    time (&now);
  } while (difftime (now, start) < loop_seconds);
  return count;
}

static double
Print (char name[], void *(*alloc) (size_t),
       void (*free_list) (struct node *), double base)
{
  time_t start, end;
  unsigned long count;
  double duration, rate, relative;

  time (&start);
  count = Loop (alloc, free_list);
  time (&end);
  duration = difftime (end, start);
  rate = count / duration;
  relative = base == 0.0 ? 1.0 : rate / base;
  printf ("%10s  %9lu  %9.2e  %9.2e  %9.2f\n", name, count, duration, rate, relative);
  return rate;
}

int
main ()
{
  double malloc_rate;

  printf ("%10s  %9s  %9s  %9s  %9s\n", "name", "count", "duration", 
          "rate", "relative");
  malloc_rate = Print ("malloc", &malloc, &FreeList, 0.0);
  Print ("Boehm", &GC_malloc, &IgnoreList, malloc_rate);
  return 0;
}


Related Reading


More Insights






Currently we allow the following HTML tags in comments:

Single tags

These tags can be used alone and don't need an ending tag.

<br> Defines a single line break

<hr> Defines a horizontal line

Matching tags

These require an ending tag - e.g. <i>italic text</i>

<a> Defines an anchor

<b> Defines bold text

<big> Defines big text

<blockquote> Defines a long quotation

<caption> Defines a table caption

<cite> Defines a citation

<code> Defines computer code text

<em> Defines emphasized text

<fieldset> Defines a border around elements in a form

<h1> This is heading 1

<h2> This is heading 2

<h3> This is heading 3

<h4> This is heading 4

<h5> This is heading 5

<h6> This is heading 6

<i> Defines italic text

<p> Defines a paragraph

<pre> Defines preformatted text

<q> Defines a short quotation

<samp> Defines sample computer code text

<small> Defines small text

<span> Defines a section in a document

<s> Defines strikethrough text

<strike> Defines strikethrough text

<strong> Defines strong text

<sub> Defines subscripted text

<sup> Defines superscripted text

<u> Defines underlined text

Dr. Dobb's encourages readers to engage in spirited, healthy debate, including taking us to task. However, Dr. Dobb's moderates all comments posted to our site, and reserves the right to modify or remove any content that it determines to be derogatory, offensive, inflammatory, vulgar, irrelevant/off-topic, racist or obvious marketing or spam. Dr. Dobb's further reserves the right to disable the profile of any commenter participating in said activities.

 
Disqus Tips To upload an avatar photo, first complete your Disqus profile. | View the list of supported HTML tags you can use to style comments. | Please read our commenting policy.
 

Video