Feature #8015: [patch] tuneable HEAP_GROWTH_FACTOR

• Status: Closed
• Assignee: authorNari (Narihiro Nakamura)
• Target version: 2.1.0

[tmm1 (Aman Karmani)]

diff --git a/gc.c b/gc.c
index 925e496..71f509f 100644
--- a/gc.c
+++ b/gc.c
@@ -71,11 +71,13 @@
#endif
#define HEAP_MIN_SLOTS 10000
#define FREE_MIN 4096
+#define HEAP_GROWTH_FACTOR 1.8

typedef struct {
unsigned int initial_malloc_limit;
unsigned int initial_heap_min_slots;
unsigned int initial_free_min;

• double initial_growth_factor;
  #if defined(ENABLE_VM_OBJSPACE) && ENABLE_VM_OBJSPACE
  int gc_stress;
  #endif
  @@ -85,6 +87,7 @@ static ruby_gc_params_t initial_params = {
  GC_MALLOC_LIMIT,
  HEAP_MIN_SLOTS,
  FREE_MIN,
• HEAP_GROWTH_FACTOR,
  #if defined(ENABLE_VM_OBJSPACE) && ENABLE_VM_OBJSPACE
  FALSE,
  #endif
  @@ -287,6 +290,7 @@ int *ruby_initial_gc_stress_ptr = &rb_objspace.gc_stress;
  #define initial_malloc_limit initial_params.initial_malloc_limit
  #define initial_heap_min_slots initial_params.initial_heap_min_slots
  #define initial_free_min initial_params.initial_free_min
  +#define initial_growth_factor initial_params.initial_growth_factor

#define is_lazy_sweeping(objspace) ((objspace)->heap.sweep_slots != 0)

@@ -605,7 +609,7 @@ initial_expand_heap(rb_objspace_t *objspace)
static void
set_heaps_increment(rb_objspace_t *objspace)
{

• size_t next_heaps_length = (size_t)(heaps_used * 1.8);

• size_t next_heaps_length = (size_t)(heaps_used * initial_growth_factor);

  if (next_heaps_length == heaps_used) {
  next_heaps_length++;
  @@ -3333,7 +3337,7 @@ rb_gc_disable(void)
  void
  rb_gc_set_params(void)
  {

• char *malloc_limit_ptr, *heap_min_slots_ptr, *free_min_ptr;

• char *malloc_limit_ptr, *heap_min_slots_ptr, *free_min_ptr, *growth_factor_ptr;

  if (rb_safe_level() > 0) return;

@@ -3360,6 +3364,16 @@ rb_gc_set_params(void)
}
}

• growth_factor_ptr = getenv("RUBY_HEAP_SLOTS_GROWTH_FACTOR");
• if (growth_factor_ptr != NULL) {
• double growth_factor_f = atof(growth_factor_ptr);
• if (RTEST(ruby_verbose))

•   fprintf(stderr, "growth_factor=%f (%f)\n", growth_factor_f, initial_growth_factor);
  

• if (growth_factor_f > 0) {

•   initial_growth_factor = growth_factor_f;
  

• }
• }
• free_min_ptr = getenv("RUBY_FREE_MIN");
  if (free_min_ptr != NULL) {
  int free_min_i = atoi(free_min_ptr);

[kosaki (Motohiro KOSAKI)]

The idea seems good.

• growth_factor_ptr = getenv("RUBY_HEAP_SLOTS_GROWTH_FACTOR");
• if (growth_factor_ptr != NULL) {

•   double growth_factor_f = atof(growth_factor_ptr);
  

atof() don't have proper error check. it should be strtod().

•   if (RTEST(ruby_verbose))
  

•       fprintf(stderr, "growth_factor=%f (%f)\n", growth_factor_f, initial_growth_factor);
  

•   if (growth_factor_f > 0) {
  

•       initial_growth_factor = growth_factor_f;
  

•   }
  

This seems don't work when growth_factor_f is less than 1.

[tmm1 (Aman Karmani)]

Thanks for the review. How about this?

@@ -3366,10 +3535,11 @@ rb_gc_set_params(void)

 growth_factor_ptr = getenv("RUBY_HEAP_SLOTS_GROWTH_FACTOR");
 if (growth_factor_ptr != NULL) {

•   double growth_factor_f = atof(growth_factor_ptr);
  

•   double growth_factor_f = strtod(growth_factor_ptr, NULL);
    if (RTEST(ruby_verbose))
  

•       fprintf(stderr, "growth_factor=%f (%f)\n", growth_factor_f, initial_growth_factor);
  

•   if (growth_factor_f > 0) {
  

•       fprintf(stderr, "heap_slots_growth_factor=%f (%f)\n",
  

•               growth_factor_f, initial_growth_factor);
  

•   if (growth_factor_f > 1) {
        initial_growth_factor = growth_factor_f;
    }
  

  }

[tmm1 (Aman Karmani)]

Are there any objections to this patch?

[authorNari (Narihiro Nakamura)]

• Assignee set to authorNari (Narihiro Nakamura)

I agree this patch. I'll merge it few days later, if there are no objections.

Thank you!

[drbrain (Eric Hodel)]

• Category set to core
• Status changed from Open to Assigned
• Target version set to 2.1.0

[authorNari (Narihiro Nakamura)]

• Status changed from Assigned to Closed
• % Done changed from 0 to 100

This issue was solved with changeset r39746.
Aman, thank you for reporting this issue.
Your contribution to Ruby is greatly appreciated.
May Ruby be with you.

---

• gc.c: allow to tune growth of heap by environment variable
  RUBY_HEAP_SLOTS_GROWTH_FACTOR. patched by tmm1(Aman Gupta).
  [Feature #8015] [ruby-core:53131]