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(************************************************************************)
(* * The Coq Proof Assistant / The Coq Development Team *)
(* v * INRIA, CNRS and contributors - Copyright 1999-2018 *)
(* <O___,, * (see CREDITS file for the list of authors) *)
(* \VV/ **************************************************************)
(* // * This file is distributed under the terms of the *)
(* * GNU Lesser General Public License Version 2.1 *)
(* * (see LICENSE file for the text of the license) *)
(************************************************************************)
(*s Logical and physical size of ocaml values. *)
(** {6 Logical sizes} *)
let c = ref 0
let s = ref 0
let b = ref 0
let m = ref 0
let rec obj_stats d t =
if Obj.is_int t then m := max d !m
else if Obj.tag t >= Obj.no_scan_tag then
if Obj.tag t = Obj.string_tag then
(c := !c + Obj.size t; b := !b + 1; m := max d !m)
else if Obj.tag t = Obj.double_tag then
(s := !s + 2; b := !b + 1; m := max d !m)
else if Obj.tag t = Obj.double_array_tag then
(s := !s + 2 * Obj.size t; b := !b + 1; m := max d !m)
else (b := !b + 1; m := max d !m)
else
let n = Obj.size t in
s := !s + n; b := !b + 1;
block_stats (d + 1) (n - 1) t
and block_stats d i t =
if i >= 0 then (obj_stats d (Obj.field t i); block_stats d (i-1) t)
let obj_stats a =
c := 0; s:= 0; b:= 0; m:= 0;
obj_stats 0 (Obj.repr a);
(!c, !s + !b, !m)
(** {6 Physical sizes} *)
(*s Pointers already visited are stored in a hash-table, where
comparisons are done using physical equality. *)
module H = Hashtbl.Make(
struct
type t = Obj.t
let equal = (==)
let hash = Hashtbl.hash
end)
let node_table = (H.create 257 : unit H.t)
let in_table o = try H.find node_table o; true with Not_found -> false
let add_in_table o = H.add node_table o ()
let reset_table () = H.clear node_table
(*s Objects are traversed recursively, as soon as their tags are less than
[no_scan_tag]. [count] records the numbers of words already visited. *)
let size_of_double = Obj.size (Obj.repr 1.0)
let count = ref 0
let rec traverse t =
if not (in_table t) && Obj.is_block t then begin
add_in_table t;
let n = Obj.size t in
let tag = Obj.tag t in
if tag < Obj.no_scan_tag then
begin
count := !count + 1 + n;
for i = 0 to n - 1 do traverse (Obj.field t i) done
end
else if tag = Obj.string_tag then
count := !count + 1 + n
else if tag = Obj.double_tag then
count := !count + size_of_double
else if tag = Obj.double_array_tag then
count := !count + 1 + size_of_double * n
else
incr count
end
(*s Sizes of objects in words and in bytes. The size in bytes is computed
system-independently according to [Sys.word_size]. *)
let size o =
reset_table ();
count := 0;
traverse (Obj.repr o);
!count
let size_b o = (size o) * (Sys.word_size / 8)
let size_kb o = (size o) / (8192 / Sys.word_size)
(** {6 Physical sizes with sharing} *)
(** This time, all the size of objects are computed with respect
to a larger object containing them all, and we only count
the new blocks not already seen earlier in the left-to-right
visit of the englobing object.
The very same object could have a zero size or not, depending
of the occurrence we're considering in the englobing object.
For speaking of occurrences, we use an [int list] for a path
of field indexes from the outmost block to the one we're looking.
In the list, the leftmost integer is the field index in the deepest
block.
*)
(** We now store in the hashtable the size (with sharing), and
also the position of the first occurrence of the object *)
let node_sizes = (H.create 257 : (int*int list) H.t)
let get_size o = H.find node_sizes o
let add_size o n pos = H.replace node_sizes o (n,pos)
let reset_sizes () = H.clear node_sizes
let global_object = ref (Obj.repr 0)
(** [sum n f] is [f 0 + f 1 + ... + f (n-1)], evaluated from left to right *)
let sum n f =
let rec loop k acc = if k >= n then acc else loop (k+1) (acc + f k)
in loop 0 0
(** Recursive visit of the main object, filling the hashtable *)
let rec compute_size o pos =
if not (Obj.is_block o) then 0
else
try
let _ = get_size o in 0 (* already seen *)
with Not_found ->
let n = Obj.size o in
add_size o (-1) pos (* temp size, for cyclic values *);
let tag = Obj.tag o in
let size =
if tag < Obj.no_scan_tag then
1 + n + sum n (fun i -> compute_size (Obj.field o i) (i::pos))
else if tag = Obj.string_tag then
1 + n
else if tag = Obj.double_tag then
size_of_double
else if tag = Obj.double_array_tag then
size_of_double * n
else
1
in
add_size o size pos;
size
(** Provides the global object in which we'll search shared sizes *)
let register_shared_size t =
let o = Obj.repr t in
reset_sizes ();
global_object := o;
ignore (compute_size o [])
(** Shared size of an object with respect to the global object given
by the last [register_shared_size] *)
let shared_size pos o =
if not (Obj.is_block o) then 0
else
let size,pos' =
try get_size o
with Not_found -> failwith "shared_size: unregistered structure ?"
in
match pos with
| Some p when p <> pos' -> 0
| _ -> size
let shared_size_of_obj t = shared_size None (Obj.repr t)
(** Shared size of the object at some positiion in the global object given
by the last [register_shared_size] *)
let shared_size_of_pos pos =
let rec obj_of_pos o = function
| [] -> o
| n::pos' ->
let o' = obj_of_pos o pos' in
assert (Obj.is_block o' && n < Obj.size o');
Obj.field o' n
in
shared_size (Some pos) (obj_of_pos !global_object pos)
(*s Total size of the allocated ocaml heap. *)
let heap_size () =
let stat = Gc.stat ()
and control = Gc.get () in
let max_words_total = stat.Gc.heap_words + control.Gc.minor_heap_size in
(max_words_total * (Sys.word_size / 8))
let heap_size_kb () = (heap_size () + 1023) / 1024
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