package mopsa

  1. Overview
  2. Docs
Legend:
Page
Library
Module
Module type
Parameter
Class
Class type
Source

Source file function_profiler.ml

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
(****************************************************************************)
(*                                                                          *)
(* This file is part of MOPSA, a Modular Open Platform for Static Analysis. *)
(*                                                                          *)
(* Copyright (C) 2017-2019 The MOPSA Project.                               *)
(*                                                                          *)
(* This program is free software: you can redistribute it and/or modify     *)
(* it under the terms of the GNU Lesser General Public License as published *)
(* by the Free Software Foundation, either version 3 of the License, or     *)
(* (at your option) any later version.                                      *)
(*                                                                          *)
(* This program is distributed in the hope that it will be useful,          *)
(* but WITHOUT ANY WARRANTY; without even the implied warranty of           *)
(* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the            *)
(* GNU Lesser General Public License for more details.                      *)
(*                                                                          *)
(* You should have received a copy of the GNU Lesser General Public License *)
(* along with this program.  If not, see <http://www.gnu.org/licenses/>.    *)
(*                                                                          *)
(****************************************************************************)

(** Hook to profile time spent in analyzing function calls *)

open Mopsa
open Hook
open Ast


module Hook =
struct

  (** {2 Hook header} *)
  (** *************** *)

  let name = "function_profiler"

  let debug fmt = Debug.debug ~channel:"function_profiler" fmt


  (** {2 Command-line options} *)
  (** ************************ *)

  (** Path of the output flame graph samples file *)
  let opt_flame_graph_path = ref ""

  let () = register_builtin_option {
      key = "-flamegraph";
      category = "Profiling";
      doc = " path where flame graphs samples are saved";
      spec = Set_string (opt_flame_graph_path,ArgExt.empty);
      default = "";
    }


  (** Resolution of the flame graph samples *)
  let opt_flame_graph_resolution = ref "ms"

  let () = register_builtin_option {
      key = "-flamegraph-resolution";
      category = "Profiling";
      doc = " resolution of the flame graph samples";
      spec = Symbol (["s"; "ms"; "us"; "ns"], (fun r -> opt_flame_graph_resolution := r));
      default = "ms";
    }



  (** {2 Timing records} *)
  (** ****************** *)

  (** Timing record of a function call *)
  type timing = {
    callstack : string list; (** Call stack *)
    time      : float;       (** Time spent in the function *)
  }


  (** Collection of past timing records *)
  let records : timing Queue.t = Queue.create ()

  (** Current timing record *)
  let cur : timing ref = ref { callstack = []; time = 0. }


  (** {2 Call stack observer} *)
  (** *********************** *)

  (** Update the state when a call is detected *)
  let call_detected (call:callsite) =
    (* First, stop the timer of previous call, save it in the queue
       and create a new timing record *)
    let t = Sys.time () in
    let timing = { !cur with time = t -. !cur.time } in
    Queue.push timing records;
    let timing = { callstack = call.call_fun_orig_name :: !cur.callstack ; time = t; } in
    cur := timing


  (** Update the state when a return is detected *)
  let return_detected () =
    (* Stop the timer of the returning call, save it in the queue and
       restore the timing record of the previous call *)
    let t = Sys.time () in
    let timing = { !cur with time = t -. !cur.time } in
    Queue.push timing records;
    let timing = { callstack = List.tl !cur.callstack ; time = t; } in
    cur := timing


  (** Observe the call stack and update the timing records *)
  let observe_callstack (cs:callstack) range =
    let depth = callstack_length cs in
    (* Decrease by 1 the current depth to take into account the first
       hidden %program call, added by init but not present in the call
       stack *)
    let cur_depth = List.length !cur.callstack - 1 in
    if depth = cur_depth then () else
    if depth = cur_depth + 1 then call_detected (callstack_top cs) else
    if depth = cur_depth - 1 then return_detected ()
    else debug "unsupported call stack configuration: current = %d, previous = %d@.current = %a@.previous = %a@." cur_depth depth (Format.pp_print_list Format.pp_print_string) !cur.callstack Callstack.pp_callstack cs


  (** {2 Statistics} *)
  (** ************** *)

  (** Print a timing record as a flame graph sample *)
  let pp_timing_sample fmt t =
    let resolution = match !opt_flame_graph_resolution with
      | "s"  -> 1.0
      | "ms" -> 1000.0
      | "us" -> 1000000.0
      | "ns" -> 1000000000.0
      | _    -> assert false
    in
    Format.fprintf fmt "%a %d"
      (Format.pp_print_list ~pp_sep:(fun fmt () -> Format.pp_print_string fmt ";") Format.pp_print_string) (List.rev t.callstack)
      (resolution *. t.time |> int_of_float)


  (** Export timing records as flame graph samples *)
  let export_flame_graph () =
    let o = open_out !opt_flame_graph_path in
    let fmt = Format.formatter_of_out_channel o in
    Queue.iter (fun t ->
        Format.fprintf fmt "%a@.%!" pp_timing_sample t
      ) records


  (** Print the statistics table *)
  let print_stats () =
    let module FunStat = MapExt.StringMap in
    (* For each function compute:
       - The total time
       - The self time: time spent in statements of the function
       - The number of times the function was called
    *)
    let total,self,times,_,longest_fname_length = Queue.fold (fun (total,self,times,last,longest_fname_length) timing ->
        let fname = List.hd timing.callstack in
        let longest_fname_length = if String.length fname > longest_fname_length then String.length fname else longest_fname_length in
        let self = FunStat.add fname (timing.time +. try FunStat.find fname self with Not_found -> 0.) self in
        let total = List.fold_left (fun total f ->
            FunStat.add f (timing.time +. try FunStat.find f total with Not_found -> 0.) total
          ) total timing.callstack
        in
        let times =
          if List.length last < List.length timing.callstack then
            FunStat.add fname (1 + try FunStat.find fname times with Not_found -> 0) times
          else
            times
        in
        total,self,times,timing.callstack,longest_fname_length
      ) (FunStat.empty,FunStat.empty,FunStat.empty,[],0) records
    in
    (* Sort functions by the total time *)
    let sorted = FunStat.bindings total |>
                 List.sort (fun (_, total) (_, total') ->
                     compare total' total
                   )
    in
    let open Format in
    printf "Functions profiling:@.";
    List.iter (fun (fname, total) ->
        printf "%s%s   %.4fs(total)   %.4fs(self)   x%d@."
          fname
          (String.make (longest_fname_length - String.length fname) ' ')
          total
          (FunStat.find fname self)
          (FunStat.find fname times)
        ;
      ) sorted



  (** {2 Events handlers} *)
  (** ******************* *)

  let init ctx =
    let t = Sys.time () in
    let timing = { callstack = ["%program"]; time = t } in
    cur := timing


  let on_before_exec route stmt man flow =
    observe_callstack (Flow.get_callstack flow) stmt.srange

  let on_after_exec route stmt man flow post = ()

  let on_before_eval route semantic exp man flow = ()

  let on_after_eval route semantic exp man flow eval =
    observe_callstack (Cases.get_ctx eval |> find_ctx Context.callstack_ctx_key) exp.erange

  let on_finish man flow =
    let t = Sys.time () in
    let timing = { !cur with time = t -. !cur.time } in
    Queue.push timing records;
    if !opt_flame_graph_path <> "" then export_flame_graph ();
    print_stats ()


end

let () =
  register_stateless_hook (module Hook)
OCaml

Innovation. Community. Security.