guile/gcbench.c

// This is adapted from a benchmark written by John Ellis and Pete Kovac
// of Post Communications.
// It was modified by Hans Boehm of Silicon Graphics.
// Translated to C++ 30 May 1997 by William D Clinger of Northeastern Univ.
// Translated to C 15 March 2000 by Hans Boehm, now at HP Labs.
//
//      This is no substitute for real applications.  No actual application
//      is likely to behave in exactly this way.  However, this benchmark was
//      designed to be more representative of real applications than other
//      Java GC benchmarks of which we are aware.
//      It attempts to model those properties of allocation requests that
//      are important to current GC techniques.
//      It is designed to be used either to obtain a single overall performance
//      number, or to give a more detailed estimate of how collector
//      performance varies with object lifetimes.  It prints the time
//      required to allocate and collect balanced binary trees of various
//      sizes.  Smaller trees result in shorter object lifetimes.  Each cycle
//      allocates roughly the same amount of memory.
//      Two data structures are kept around during the entire process, so
//      that the measured performance is representative of applications
//      that maintain some live in-memory data.  One of these is a tree
//      containing many pointers.  The other is a large array containing
//      double precision floating point numbers.  Both should be of comparable
//      size.
//
//      The results are only really meaningful together with a specification
//      of how much memory was used.  It is possible to trade memory for
//      better time performance.  This benchmark should be run in a 32 MB
//      heap, though we don't currently know how to enforce that uniformly.
//
//      Unlike the original Ellis and Kovac benchmark, we do not attempt
//      measure pause times.  This facility should eventually be added back
//      in.  There are several reasons for omitting it for now.  The original
//      implementation depended on assumptions about the thread scheduler
//      that don't hold uniformly.  The results really measure both the
//      scheduler and GC.  Pause time measurements tend to not fit well with
//      current benchmark suites.  As far as we know, none of the current
//      commercial Java implementations seriously attempt to minimize GC pause
//      times.

#include <stdio.h>
#include <stdlib.h>
#include <sys/time.h>

#include "assert.h"
#include "gcbench-types.h"
#include "gc.h"

static const int long_lived_tree_depth = 16; // about 4Mb
static const int array_size = 500000; // about 4Mb
static const int min_tree_depth = 4;
static const int max_tree_depth = 16;

struct Node {
  GC_HEADER;
  struct Node * left;
  struct Node * right;
  int i, j;
};

struct DoubleArray {
  GC_HEADER;
  size_t length;
  double values[0];
};

static inline size_t node_size(Node *obj) {
  return sizeof(Node);
}
static inline size_t double_array_size(DoubleArray *array) {
  return sizeof(*array) + array->length * sizeof(double);
}
static inline void
visit_node_fields(Node *node,
                  void (*visit)(void **loc, void *visit_data),
                  void *visit_data) {
  visit((void**)&node->left, visit_data);
  visit((void**)&node->right, visit_data);
}
static inline void
visit_double_array_fields(DoubleArray *obj,
                          void (*visit)(void **loc, void *visit_data),
                          void *visit_data) {
}

typedef HANDLE_TO(Node) NodeHandle;
typedef HANDLE_TO(DoubleArray) DoubleArrayHandle;

static Node* allocate_node(struct context *cx) {
  // memset to 0 by the collector.
  return allocate(cx, ALLOC_KIND_NODE, sizeof (Node));
}

static DoubleArray* allocate_double_array(struct context *cx,
                                                 size_t size) {
  // May be uninitialized.
  DoubleArray *ret =
    allocate_pointerless(cx, ALLOC_KIND_DOUBLE_ARRAY,
                         sizeof(DoubleArray) + sizeof (double) * size);
  ret->length = size;
  return ret;
}

static unsigned long current_time(void)
{
  struct timeval t = { 0 };
  gettimeofday(&t, NULL);
  return t.tv_sec * 1000 * 1000 + t.tv_usec;
}

static double elapsed_millis(unsigned long start) {
  return (current_time() - start) * 1e-3;
}

// Nodes used by a tree of a given size
static int tree_size(int i) {
  return ((1 << (i + 1)) - 1);
}

// Number of iterations to use for a given tree depth
static int compute_num_iters(int i) {
  return 2 * tree_size(max_tree_depth + 2) / tree_size(i);
}

// Build tree top down, assigning to older objects.
static void populate(struct context *cx, int depth, Node *node) {
  if (depth <= 0)
    return;

  NodeHandle self = { node };
  PUSH_HANDLE(cx, self);
  NodeHandle l = { allocate_node(cx) };
  PUSH_HANDLE(cx, l);
  NodeHandle r = { allocate_node(cx) };
  PUSH_HANDLE(cx, r);

  set_field((void**)&HANDLE_REF(self)->left, HANDLE_REF(l));
  set_field((void**)&HANDLE_REF(self)->right, HANDLE_REF(r));

  populate(cx, depth-1, HANDLE_REF(self)->left);
  populate(cx, depth-1, HANDLE_REF(self)->right);

  POP_HANDLE(cx);
  POP_HANDLE(cx);
  POP_HANDLE(cx);
}

// Build tree bottom-up
static Node* make_tree(struct context *cx, int depth) {
  if (depth <= 0)
    return allocate_node(cx);

  NodeHandle left = { make_tree(cx, depth-1) };
  PUSH_HANDLE(cx, left);
  NodeHandle right = { make_tree(cx, depth-1) };
  PUSH_HANDLE(cx, right);

  Node *result = allocate_node(cx);
  init_field((void**)&result->left, HANDLE_REF(left));
  init_field((void**)&result->right, HANDLE_REF(right));

  POP_HANDLE(cx);
  POP_HANDLE(cx);

  return result;
}

static void validate_tree(Node *tree, int depth) {
#ifndef NDEBUG
  ASSERT_EQ(tree->i, 0);
  ASSERT_EQ(tree->j, 0);
  if (depth == 0) {
    ASSERT(!tree->left);
    ASSERT(!tree->right);
  } else {
    ASSERT(tree->left);
    ASSERT(tree->right);
    validate_tree(tree->left, depth - 1);
    validate_tree(tree->right, depth - 1);
  }
#endif
}

static void time_construction(struct context *cx, int depth) {
  int num_iters = compute_num_iters(depth);
  NodeHandle temp_tree = { NULL };
  PUSH_HANDLE(cx, temp_tree);

  printf("Creating %d trees of depth %d\n", num_iters, depth);

  {
    unsigned long start = current_time();
    for (int i = 0; i < num_iters; ++i) {
      HANDLE_SET(temp_tree, allocate_node(cx));
      populate(cx, depth, HANDLE_REF(temp_tree));
      validate_tree(HANDLE_REF(temp_tree), depth);
      HANDLE_SET(temp_tree, NULL);
    }
    printf("\tTop down construction took %.3f msec\n",
           elapsed_millis(start));
  }

  {
    long start = current_time();
    for (int i = 0; i < num_iters; ++i) {
      HANDLE_SET(temp_tree, make_tree(cx, depth));
      validate_tree(HANDLE_REF(temp_tree), depth);
      HANDLE_SET(temp_tree, NULL);
    }
    printf("\tBottom up construction took %.3f msec\n",
           elapsed_millis(start));
  }

  POP_HANDLE(cx);
}

int main(int argc, char *argv[]) {
  // Define size of Node without any GC header.
  size_t sizeof_node = 2 * sizeof(Node*) + 2 * sizeof(int);
  size_t sizeof_double_array = sizeof(size_t);
  size_t heap_max_live =
    tree_size(long_lived_tree_depth) * sizeof_node +
    tree_size(max_tree_depth) * sizeof_node +
    sizeof_double_array + sizeof(double) * array_size;
  if (argc != 2) {
    fprintf(stderr, "usage: %s MULTIPLIER\n", argv[0]);
    return 1;
  }

  double multiplier = atof(argv[1]);

  if (!(1.0 < multiplier && multiplier < 100)) {
    fprintf(stderr, "Failed to parse heap multiplier '%s'\n", argv[2]);
    return 1;
  }

  size_t heap_size = heap_max_live * multiplier;
  struct context *cx = initialize_gc(heap_size);
  if (!cx) {
    fprintf(stderr, "Failed to initialize GC with heap size %zu bytes\n",
            heap_size);
    return 1;
  }

  NodeHandle root = { NULL };
  NodeHandle long_lived_tree = { NULL };
  NodeHandle temp_tree = { NULL };
  DoubleArrayHandle array = { NULL };

  PUSH_HANDLE(cx, root);
  PUSH_HANDLE(cx, long_lived_tree);
  PUSH_HANDLE(cx, temp_tree);
  PUSH_HANDLE(cx, array);

  printf("Garbage Collector Test\n");
  printf(" Live storage will peak at %zd bytes.\n\n", heap_max_live);
  print_start_gc_stats(cx);

  unsigned long start = current_time();
        
  // Create a long lived object
  printf(" Creating a long-lived binary tree of depth %d\n",
         long_lived_tree_depth);
  HANDLE_SET(long_lived_tree, allocate_node(cx));
  populate(cx, long_lived_tree_depth, HANDLE_REF(long_lived_tree));

  // Create long-lived array, filling half of it
  printf(" Creating a long-lived array of %d doubles\n", array_size);
  HANDLE_SET(array, allocate_double_array(cx, array_size));
  for (int i = 0; i < array_size/2; ++i) {
    HANDLE_REF(array)->values[i] = 1.0/i;
  }

  for (int d = min_tree_depth; d <= max_tree_depth; d += 2) {
    time_construction(cx, d);
  }

  validate_tree(HANDLE_REF(long_lived_tree), long_lived_tree_depth);

  // Fake reference to LongLivedTree and array to keep them from being optimized
  // away.
  if (HANDLE_REF(long_lived_tree) == 0
      || HANDLE_REF(array)->values[1000] != 1.0/1000)
    fprintf(stderr, "Failed\n");

  printf("Completed in %.3f msec\n", elapsed_millis(start));
  print_end_gc_stats(cx);

  POP_HANDLE(cx);
  POP_HANDLE(cx);
  POP_HANDLE(cx);
  POP_HANDLE(cx);
}