Memprof tracking of interned data.

2019-05-29 16:51:10 +02:00 · 2019-05-29 16:51:10 +02:00 · 90073e96e5
parent c0dbbfdd71
commit 90073e96e5
11 changed files with 307 additions and 40 deletions
--- a/5
+++ b/5
@ -106,9 +106,8 @@ Working version

 - #8634: Statistical memory profiling provided by the Gc.Memprof
   module.
-   Incomplete version: does not sample
-     - objects allocated in the minor heap in native mode,
-     - objects allocated by de-marshalling.
+   Incomplete version: does not sample objects allocated in the minor
+   heap in native mode
   (Jacques-Henri Jourdan, review by Stephen Dolan, Gabriel Scherer and
    Damien Doligez)

--- a/runtime/.depend
+++ b/runtime/.depend
@ -149,7 +149,8 @@ intern_b.$(O): intern.c caml/alloc.h caml/misc.h caml/config.h caml/m.h \
 caml/callback.h caml/config.h caml/custom.h caml/fail.h caml/gc.h \
 caml/intext.h caml/io.h caml/io.h caml/md5.h caml/memory.h caml/gc.h \
 caml/major_gc.h caml/freelist.h caml/minor_gc.h caml/address_class.h \
- caml/domain.h caml/mlvalues.h caml/misc.h caml/reverse.h
+ caml/domain.h caml/mlvalues.h caml/misc.h caml/reverse.h caml/memprof.h \
+ caml/roots.h caml/memory.h
 interp_b.$(O): interp.c caml/alloc.h caml/misc.h caml/config.h caml/m.h \
 caml/s.h caml/mlvalues.h caml/domain_state.h caml/domain_state.tbl \
 caml/backtrace.h caml/exec.h caml/callback.h caml/debugger.h caml/fail.h \
@ -509,7 +510,8 @@ intern_bd.$(O): intern.c caml/alloc.h caml/misc.h caml/config.h caml/m.h \
 caml/callback.h caml/config.h caml/custom.h caml/fail.h caml/gc.h \
 caml/intext.h caml/io.h caml/io.h caml/md5.h caml/memory.h caml/gc.h \
 caml/major_gc.h caml/freelist.h caml/minor_gc.h caml/address_class.h \
- caml/domain.h caml/mlvalues.h caml/misc.h caml/reverse.h
+ caml/domain.h caml/mlvalues.h caml/misc.h caml/reverse.h caml/memprof.h \
+ caml/roots.h caml/memory.h
 interp_bd.$(O): interp.c caml/alloc.h caml/misc.h caml/config.h caml/m.h \
 caml/s.h caml/mlvalues.h caml/domain_state.h caml/domain_state.tbl \
 caml/backtrace.h caml/exec.h caml/callback.h caml/debugger.h caml/fail.h \
@ -864,7 +866,8 @@ intern_bi.$(O): intern.c caml/alloc.h caml/misc.h caml/config.h caml/m.h \
 caml/callback.h caml/config.h caml/custom.h caml/fail.h caml/gc.h \
 caml/intext.h caml/io.h caml/io.h caml/md5.h caml/memory.h caml/gc.h \
 caml/major_gc.h caml/freelist.h caml/minor_gc.h caml/address_class.h \
- caml/domain.h caml/mlvalues.h caml/misc.h caml/reverse.h
+ caml/domain.h caml/mlvalues.h caml/misc.h caml/reverse.h caml/memprof.h \
+ caml/roots.h caml/memory.h
 interp_bi.$(O): interp.c caml/alloc.h caml/misc.h caml/config.h caml/m.h \
 caml/s.h caml/mlvalues.h caml/domain_state.h caml/domain_state.tbl \
 caml/backtrace.h caml/exec.h caml/callback.h caml/debugger.h caml/fail.h \
@ -1219,7 +1222,8 @@ intern_bpic.$(O): intern.c caml/alloc.h caml/misc.h caml/config.h caml/m.h \
 caml/callback.h caml/config.h caml/custom.h caml/fail.h caml/gc.h \
 caml/intext.h caml/io.h caml/io.h caml/md5.h caml/memory.h caml/gc.h \
 caml/major_gc.h caml/freelist.h caml/minor_gc.h caml/address_class.h \
- caml/domain.h caml/mlvalues.h caml/misc.h caml/reverse.h
+ caml/domain.h caml/mlvalues.h caml/misc.h caml/reverse.h caml/memprof.h \
+ caml/roots.h caml/memory.h
 interp_bpic.$(O): interp.c caml/alloc.h caml/misc.h caml/config.h caml/m.h \
 caml/s.h caml/mlvalues.h caml/domain_state.h caml/domain_state.tbl \
 caml/backtrace.h caml/exec.h caml/callback.h caml/debugger.h caml/fail.h \
@ -1571,7 +1575,8 @@ intern_n.$(O): intern.c caml/alloc.h caml/misc.h caml/config.h caml/m.h \
 caml/callback.h caml/config.h caml/custom.h caml/fail.h caml/gc.h \
 caml/intext.h caml/io.h caml/io.h caml/md5.h caml/memory.h caml/gc.h \
 caml/major_gc.h caml/freelist.h caml/minor_gc.h caml/address_class.h \
- caml/domain.h caml/mlvalues.h caml/misc.h caml/reverse.h
+ caml/domain.h caml/mlvalues.h caml/misc.h caml/reverse.h caml/memprof.h \
+ caml/roots.h caml/memory.h
 interp_n.$(O): interp.c caml/alloc.h caml/misc.h caml/config.h caml/m.h \
 caml/s.h caml/mlvalues.h caml/domain_state.h caml/domain_state.tbl \
 caml/backtrace.h caml/exec.h caml/callback.h caml/debugger.h caml/fail.h \
@ -1928,7 +1933,8 @@ intern_nd.$(O): intern.c caml/alloc.h caml/misc.h caml/config.h caml/m.h \
 caml/callback.h caml/config.h caml/custom.h caml/fail.h caml/gc.h \
 caml/intext.h caml/io.h caml/io.h caml/md5.h caml/memory.h caml/gc.h \
 caml/major_gc.h caml/freelist.h caml/minor_gc.h caml/address_class.h \
- caml/domain.h caml/mlvalues.h caml/misc.h caml/reverse.h
+ caml/domain.h caml/mlvalues.h caml/misc.h caml/reverse.h caml/memprof.h \
+ caml/roots.h caml/memory.h
 interp_nd.$(O): interp.c caml/alloc.h caml/misc.h caml/config.h caml/m.h \
 caml/s.h caml/mlvalues.h caml/domain_state.h caml/domain_state.tbl \
 caml/backtrace.h caml/exec.h caml/callback.h caml/debugger.h caml/fail.h \
@ -2280,7 +2286,8 @@ intern_ni.$(O): intern.c caml/alloc.h caml/misc.h caml/config.h caml/m.h \
 caml/callback.h caml/config.h caml/custom.h caml/fail.h caml/gc.h \
 caml/intext.h caml/io.h caml/io.h caml/md5.h caml/memory.h caml/gc.h \
 caml/major_gc.h caml/freelist.h caml/minor_gc.h caml/address_class.h \
- caml/domain.h caml/mlvalues.h caml/misc.h caml/reverse.h
+ caml/domain.h caml/mlvalues.h caml/misc.h caml/reverse.h caml/memprof.h \
+ caml/roots.h caml/memory.h
 interp_ni.$(O): interp.c caml/alloc.h caml/misc.h caml/config.h caml/m.h \
 caml/s.h caml/mlvalues.h caml/domain_state.h caml/domain_state.tbl \
 caml/backtrace.h caml/exec.h caml/callback.h caml/debugger.h caml/fail.h \
@ -2632,7 +2639,8 @@ intern_npic.$(O): intern.c caml/alloc.h caml/misc.h caml/config.h caml/m.h \
 caml/callback.h caml/config.h caml/custom.h caml/fail.h caml/gc.h \
 caml/intext.h caml/io.h caml/io.h caml/md5.h caml/memory.h caml/gc.h \
 caml/major_gc.h caml/freelist.h caml/minor_gc.h caml/address_class.h \
- caml/domain.h caml/mlvalues.h caml/misc.h caml/reverse.h
+ caml/domain.h caml/mlvalues.h caml/misc.h caml/reverse.h caml/memprof.h \
+ caml/roots.h caml/memory.h
 interp_npic.$(O): interp.c caml/alloc.h caml/misc.h caml/config.h caml/m.h \
 caml/s.h caml/mlvalues.h caml/domain_state.h caml/domain_state.tbl \
 caml/backtrace.h caml/exec.h caml/callback.h caml/debugger.h caml/fail.h \
--- a/runtime/caml/memprof.h
+++ b/runtime/caml/memprof.h
@ -28,6 +28,7 @@ extern void caml_memprof_handle_postponed();

 extern void caml_memprof_track_alloc_shr(value block);
 extern void caml_memprof_track_young(tag_t tag, uintnat wosize, int from_caml);
+extern void caml_memprof_track_interned(header_t* block, header_t* blockend);

 extern void caml_memprof_renew_minor_sample(void);
 extern value* caml_memprof_young_trigger;
--- a/runtime/intern.c
+++ b/runtime/intern.c
@ -34,6 +34,7 @@
 #include "caml/mlvalues.h"
 #include "caml/misc.h"
 #include "caml/reverse.h"
+#include "caml/memprof.h"

 static unsigned char * intern_src;
 /* Reading pointer in block holding input data. */
@ -659,8 +660,9 @@ static void intern_alloc(mlsize_t whsize, mlsize_t num_objects,
    CAMLassert(intern_obj_table == NULL);
 }

-static void intern_add_to_heap(mlsize_t whsize)
+static header_t* intern_add_to_heap(mlsize_t whsize)
 {
+  header_t* res = NULL;
  /* Add new heap chunk to heap if needed */
  if (intern_extra_block != NULL) {
    /* If heap chunk not filled totally, build free block at end */
@ -675,11 +677,32 @@ static void intern_add_to_heap(mlsize_t whsize)
    }
    caml_allocated_words +=
      Wsize_bsize ((char *) intern_dest - intern_extra_block);
-    caml_add_to_heap(intern_extra_block);
+    if(caml_add_to_heap(intern_extra_block) != 0) {
+      intern_cleanup();
+      caml_raise_out_of_memory();
+    }
+    res = (header_t*)intern_extra_block;
    intern_extra_block = NULL; // To prevent intern_cleanup freeing it
-  } else {
+  } else if(intern_block != 0) { /* [intern_block = 0] when [whsize = 0]  */
+    res = Hp_val(intern_block);
    intern_block = 0; // To prevent intern_cleanup rewriting its header
  }
+  return res;
+}
+
+static value intern_end(value res, mlsize_t whsize) {
+  header_t *block = intern_add_to_heap(whsize);
+  header_t *blockend = intern_dest;
+
+  /* Free everything */
+  intern_cleanup();
+
+  /* Memprof tracking has to be done here, because unmarshalling can
+     still fail until now. */
+  if(block != NULL)
+    caml_memprof_track_interned(block, blockend);
+
+  return caml_check_urgent_gc(res);
 }

 /* Parsing the header */
@ -776,16 +799,16 @@ static value caml_input_val_core(struct channel *chan, int outside_heap)
  intern_alloc(h.whsize, h.num_objects, outside_heap);
  /* Fill it in */
  intern_rec(&res);
-  if (!outside_heap) {
-    intern_add_to_heap(h.whsize);
-  } else {
+  if (!outside_heap)
+    return intern_end(res, h.whsize);
+  else {
    caml_disown_for_heap(intern_extra_block);
    intern_extra_block = NULL;
    intern_block = 0;
+    /* Free everything */
+    intern_cleanup();
+    return caml_check_urgent_gc(res);
  }
-  /* Free everything */
-  intern_cleanup();
-  return caml_check_urgent_gc(res);
 }

 value caml_input_val(struct channel* chan)
@ -835,10 +858,7 @@ CAMLexport value caml_input_val_from_bytes(value str, intnat ofs)
  intern_src = &Byte_u(str, ofs + h.header_len); /* If a GC occurred */
  /* Fill it in */
  intern_rec(&obj);
-  intern_add_to_heap(h.whsize);
-  /* Free everything */
-  intern_cleanup();
-  CAMLreturn (caml_check_urgent_gc(obj));
+  CAMLreturn (intern_end(obj, h.whsize));
 }

 CAMLprim value caml_input_value_from_string(value str, value ofs)
@ -858,10 +878,7 @@ static value input_val_from_block(struct marshal_header * h)
  intern_alloc(h->whsize, h->num_objects, 0);
  /* Fill it in */
  intern_rec(&obj);
-  intern_add_to_heap(h->whsize);
-  /* Free internal data structures */
-  intern_cleanup();
-  return caml_check_urgent_gc(obj);
+  return (intern_end(obj, h->whsize));
 }

 CAMLexport value caml_input_value_from_malloc(char * data, intnat ofs)
--- a/runtime/memprof.c
+++ b/runtime/memprof.c
@ -179,7 +179,7 @@ CAMLprim value caml_memprof_set(value v)
 enum ml_alloc_kind {
  Minor = Val_long(0),
  Major = Val_long(1),
-  Serialized = Val_long(2)
+  Unmarshalled = Val_long(2)
 };

 /* When we call do_callback, we suspend/resume sampling. In order to
@ -287,13 +287,13 @@ static void purge_postponed_queue(void)
   block is allocated, but not yet initialized, so that the heap
   invariants are broken. */
 static void register_postponed_callback(value block, uintnat occurrences,
-                                        enum ml_alloc_kind kind)
+                                        enum ml_alloc_kind kind,
+                                        value* callstack)
 {
-  value callstack;
  struct postponed_block* new_hd;
  if (occurrences == 0) return;
-  callstack = capture_callstack_postponed();
-  if (callstack == 0) return;    /* OOM */
+  if (*callstack == 0) *callstack = capture_callstack_postponed();
+  if (*callstack == 0) return;    /* OOM */

  new_hd = postponed_next(postponed_hd);
  if (new_hd == postponed_tl) {
@ -319,7 +319,7 @@ static void register_postponed_callback(value block, uintnat occurrences,
  }

  postponed_hd->block = block;
-  postponed_hd->callstack = callstack;
+  postponed_hd->callstack = *callstack;
  postponed_hd->occurrences = occurrences;
  postponed_hd->kind = kind;
  postponed_hd = new_hd;
@ -371,11 +371,12 @@ void caml_memprof_scan_roots(scanning_action f) {

 void caml_memprof_track_alloc_shr(value block)
 {
+  value callstack = 0;
  CAMLassert(Is_in_heap(block));
  /* This test also makes sure memprof is initialized. */
  if (lambda == 0 || caml_memprof_suspended) return;
  register_postponed_callback(
-      block, mt_generate_binom(Whsize_val(block)), Major);
+      block, mt_generate_binom(Whsize_val(block)), Major, &callstack);
 }

 /* Shifts the next sample in the minor heap by [n] words. Essentially,
@ -438,8 +439,9 @@ void caml_memprof_track_young(tag_t tag, uintnat wosize, int from_caml)
                      - Caml_state->young_ptr) + 1;

  if (!from_caml) {
+    value callstack = 0;
    register_postponed_callback(Val_hp(Caml_state->young_ptr), occurrences,
-                                Minor);
+                                Minor, &callstack);
    caml_memprof_renew_minor_sample();
    CAMLreturn0;
  }
@ -493,3 +495,39 @@ void caml_memprof_track_young(tag_t tag, uintnat wosize, int from_caml)

  CAMLreturn0;
 }
+
+void caml_memprof_track_interned(header_t* block, header_t* blockend) {
+  header_t *p;
+  value callstack = 0;
+
+  if(lambda == 0 || caml_memprof_suspended)
+    return;
+
+  /* We have to select the sampled blocks before sampling them,
+     because sampling may trigger GC, and then blocks can escape from
+     [block, blockend[. So we use the postponing machinery for
+     selecting blocks. [intern.c] will call [check_urgent_gc] which
+     will call [caml_memprof_handle_postponed] in turn. */
+  p = block;
+  while(1) {
+    uintnat next_sample = mt_generate_geom();
+    header_t *next_sample_p, *next_p;
+    if(next_sample > blockend - p)
+      break;
+    /* [next_sample_p] is the block *following* the next sampled
+       block! */
+    next_sample_p = p + next_sample;
+
+    while(1) {
+      next_p = p + Whsize_hp(p);
+      if(next_p >= next_sample_p) break;
+      p = next_p;
+    }
+
+    register_postponed_callback(
+      Val_hp(p), mt_generate_binom(next_p - next_sample_p) + 1,
+      Unmarshalled, &callstack);
+
+    p = next_p;
+  }
+}
--- a/stdlib/gc.ml
+++ b/stdlib/gc.ml
@ -124,7 +124,7 @@ module Memprof =
    type alloc_kind =
      | Minor
      | Major
-      | Serialized
+      | Unmarshalled

    type sample_info = {
        n_samples: int; kind: alloc_kind; tag: int;
--- a/stdlib/gc.mli
+++ b/stdlib/gc.mli
@ -401,12 +401,11 @@ module Memprof :
    type alloc_kind =
      | Minor
      | Major
-      | Serialized
+      | Unmarshalled
    (** Allocation kinds
        - [Minor] : the allocation took place in the minor heap.
        - [Major] : the allocation took place in the major heap.
-        - [Serialized] : the allocation happened during a
-          deserialization. *)
+        - [Unmarshalled] : the allocation happened while unmarshalling. *)

    type sample_info = {
        n_samples: int;
--- a/testsuite/tests/statmemprof/intern.byte.reference
+++ b/testsuite/tests/statmemprof/intern.byte.reference
@ -0,0 +1,13 @@
+check_nosample
+check_ephe_full_major
+check_no_nested
+check_distrib 2 3000 3 0.000010
+check_distrib 2 3000 1 0.000100
+check_distrib 2 2000 1 0.010000
+check_distrib 2 2000 1 0.900000
+check_distrib 300000 300000 20 0.100000
+check_callstack
+Raised by primitive operation at file "intern.ml", line 32, characters 14-35
+Called from file "intern.ml", line 168, characters 2-25
+Called from file "intern.ml", line 174, characters 9-27
+OK !
--- a/testsuite/tests/statmemprof/intern.ml
+++ b/testsuite/tests/statmemprof/intern.ml
@ -0,0 +1,177 @@
+(* TEST
+   flags = "-g"
+   * bytecode
+     reference = "${test_source_directory}/intern.byte.reference"
+   * native
+     reference = "${test_source_directory}/intern.opt.reference"
+     compare_programs = "false"
+*)
+
+open Gc.Memprof
+
+type t = Dummy of int (* Skip tag 0. *) | I of int | II of int * int | Cons of t
+let rec t_of_len = function
+  | len when len <= 1 -> assert false
+  | 2 -> I 1
+  | 3 -> II (2, 3)
+  | len -> Cons (t_of_len (len - 2))
+
+let marshalled_data = Hashtbl.create 17
+let[@inline never] get_marshalled_data len : t =
+  Marshal.from_string (Hashtbl.find marshalled_data len) 0
+let precompute_marshalled_data lo hi =
+  for len = lo to hi do
+    if not (Hashtbl.mem marshalled_data len) then
+      Hashtbl.add marshalled_data len (Marshal.to_string (t_of_len len) [])
+  done
+
+let root = ref []
+let[@inline never] do_intern lo hi cnt keep =
+  for j = 0 to cnt-1 do
+    for i = lo to hi do
+      root := get_marshalled_data i :: !root
+    done;
+    if not keep then root := []
+  done
+
+let check_nosample () =
+  Printf.printf "check_nosample\n%!";
+  precompute_marshalled_data 2 3000;
+  start {
+      sampling_rate = 0.;
+      callstack_size = 10;
+      callback = fun _ ->
+        Printf.printf "Callback called with sampling_rate = 0\n";
+        assert(false)
+  };
+  do_intern 2 3000 1 false
+
+let () = check_nosample ()
+
+let check_ephe_full_major () =
+  Printf.printf "check_ephe_full_major\n%!";
+  precompute_marshalled_data 2 3000;
+  let ephes = ref [] in
+  start {
+    sampling_rate = 0.01;
+    callstack_size = 10;
+    callback = fun _ ->
+      let res = Ephemeron.K1.create () in
+      ephes := res :: !ephes;
+      Some res
+  };
+  do_intern 2 3000 1 true;
+  stop ();
+  List.iter (fun e -> assert (Ephemeron.K1.check_key e)) !ephes;
+  Gc.full_major ();
+  List.iter (fun e -> assert (Ephemeron.K1.check_key e)) !ephes;
+  root := [];
+  Gc.full_major ();
+  List.iter (fun e -> assert (not (Ephemeron.K1.check_key e))) !ephes
+
+let () = check_ephe_full_major ()
+
+let check_no_nested () =
+  Printf.printf "check_no_nested\n%!";
+  precompute_marshalled_data 2 300;
+  let in_callback = ref false in
+  start {
+      (* FIXME: we should use 1. to make sure the block is sampled,
+       but the runtime does an infinite loop in native mode in this
+       case. This bug will go away when the sampling of natively
+       allocated will be correctly implemented. *)
+      sampling_rate = 0.5;
+      callstack_size = 10;
+      callback = fun _ ->
+        assert (not !in_callback);
+        in_callback := true;
+        do_intern 100 200 1 false;
+        in_callback := false;
+        None
+  };
+  do_intern 100 200 1 false;
+  stop ()
+
+let () = check_no_nested ()
+
+let check_distrib lo hi cnt rate =
+  Printf.printf "check_distrib %d %d %d %f\n%!" lo hi cnt rate;
+  precompute_marshalled_data lo hi;
+  let smp = ref 0 in
+  start {
+      sampling_rate = rate;
+      callstack_size = 10;
+      callback = fun info ->
+        (* We also allocate the list constructor in the minor heap. *)
+        if info.kind = Unmarshalled then begin
+          begin match info.tag, info.size with
+          | 1, 1 | 2, 2 | 3, 1 -> ()
+          | _ -> assert false
+          end;
+          assert (info.n_samples > 0);
+          smp := !smp + info.n_samples
+        end;
+        None
+    };
+  do_intern lo hi cnt false;
+  stop ();
+
+  (* The probability distribution of the number of samples follows a
+     binomial distribution of parameters tot_alloc and rate. Given
+     that tot_alloc*rate and tot_alloc*(1-rate) are large (i.e., >
+     100), this distribution is approximately equal to a normal
+     distribution. We compute a 1e-8 confidence interval for !smp
+     using quantiles of the normal distribution, and check that we are
+     in this confidence interval. *)
+  let tot_alloc = cnt*(lo+hi)*(hi-lo+1)/2 in
+  assert (float tot_alloc *. rate > 100. &&
+          float tot_alloc *. (1. -. rate) > 100.);
+  let mean = float tot_alloc *. rate in
+  let stddev = sqrt (float tot_alloc *. rate *. (1. -. rate)) in
+  (* This assertion has probability to fail close to 1e-8. *)
+  assert (abs_float (mean -. float !smp) <= stddev *. 5.7)
+
+let () =
+  check_distrib 2 3000 3 0.00001;
+  check_distrib 2 3000 1 0.0001;
+  check_distrib 2 2000 1 0.01;
+  check_distrib 2 2000 1 0.9;
+  check_distrib 300000 300000 20 0.1
+
+(* FIXME : in bytecode mode, the function [caml_get_current_callstack_impl],
+   which is supposed to capture the current call stack, does not have access
+   to the current value of [pc]. Therefore, depending on how the C call is
+   performed, we may miss the first call stack slot in the captured backtraces.
+   This is the reason why the reference file is different in native and
+   bytecode modes.
+
+   Note that [Printexc.get_callstack] does not suffer from this problem, because
+   this function is actually an automatically generated stub which performs th
+   C call. This is because [Printexc.get_callstack] is not declared as external
+   in the mli file. *)
+
+let[@inline never] check_callstack () =
+  Printf.printf "check_callstack\n%!";
+  precompute_marshalled_data 2 300;
+  let callstack = ref None in
+  start {
+      (* FIXME: we should use 1. to make sure the block is sampled,
+       but the runtime does an infinite loop in native mode in this
+       case. This bug will go away when the sampling of natively
+       allocated will be correctly implemented. *)
+      sampling_rate = 0.5;
+      callstack_size = 10;
+      callback = fun info ->
+        if info.kind = Unmarshalled then callstack := Some info.callstack;
+        None
+    };
+  do_intern 2 300 1 false;
+  stop ();
+  match !callstack with
+  | None -> assert false
+  | Some cs -> Printexc.print_raw_backtrace stdout cs
+
+let () = check_callstack ()
+
+let () =
+  Printf.printf "OK !\n"
--- a/testsuite/tests/statmemprof/intern.opt.reference
+++ b/testsuite/tests/statmemprof/intern.opt.reference
@ -0,0 +1,14 @@
+check_nosample
+check_ephe_full_major
+check_no_nested
+check_distrib 2 3000 3 0.000010
+check_distrib 2 3000 1 0.000100
+check_distrib 2 2000 1 0.010000
+check_distrib 2 2000 1 0.900000
+check_distrib 300000 300000 20 0.100000
+check_callstack
+Raised by primitive operation at file "marshal.ml", line 61, characters 9-35
+Called from file "intern.ml", line 32, characters 14-35
+Called from file "intern.ml", line 168, characters 2-25
+Called from file "intern.ml", line 174, characters 9-27
+OK !
--- a/testsuite/tests/statmemprof/ocamltests
+++ b/testsuite/tests/statmemprof/ocamltests
@ -2,3 +2,4 @@ arrays_in_major.ml
 arrays_in_minor.ml
 lists_in_minor.ml
 exception_callback.ml
+intern.ml