diff --git a/NEWS b/NEWS
index 8cb302c9e..446769524 100644
--- a/NEWS
+++ b/NEWS
@@ -6,6 +6,12 @@ New in spot 2.1.2.dev (not yet released)
     LTL over finite words) model checking to LTL model checking.  This
     is based on a transformation by De Giacomo & Vardi (IJCAI'13).
 
+  * autfilt, dstar2tgba, ltl2tgba, ltlcross, ltldo learned to time any
+    task in a more precise way thanks to %R, %[LETTER]R option. User time,
+    system time or children processing time or ... (see --help) can be
+    measured separately. A typical use-case is to exclude time spent
+    inside ltldo by keeping only time spent in each executed tool.
+
   Library:
 
   * from_ltlf() is a new function implementing the --from-ltlf
diff --git a/bin/autfilt.cc b/bin/autfilt.cc
index 848f9f189..4abab6196 100644
--- a/bin/autfilt.cc
+++ b/bin/autfilt.cc
@@ -963,8 +963,8 @@ namespace
     process_automaton(const spot::const_parsed_aut_ptr& haut,
                       const char* filename)
     {
-      spot::stopwatch sw;
-      sw.start();
+      process_timer timer;
+      timer.start();
 
       // If --stats or --name is used, duplicate the automaton so we
       // never modify the original automaton (e.g. with
@@ -1183,8 +1183,7 @@ namespace
               run->project(aut)->highlight(word_aut.second);
           }
 
-      const double conversion_time = sw.stop();
-
+      timer.stop();
       if (opt->uniq)
         {
           auto tmp =
@@ -1197,8 +1196,7 @@ namespace
 
       ++match_count;
 
-      printer.print(aut, nullptr, filename, -1, conversion_time, haut,
-                    prefix, suffix);
+      printer.print(aut, timer, nullptr, filename, -1, haut, prefix, suffix);
 
       if (opt_max_count >= 0 && match_count >= opt_max_count)
         abort_run = true;
diff --git a/bin/common_aoutput.cc b/bin/common_aoutput.cc
index d2c37b15e..db3f4363a 100644
--- a/bin/common_aoutput.cc
+++ b/bin/common_aoutput.cc
@@ -20,20 +20,19 @@
 #include "common_sys.hh"
 #include "error.h"
 #include "argmatch.h"
-
 #include "common_aoutput.hh"
 #include "common_post.hh"
 #include "common_cout.hh"
 
+#include <unistd.h>
 #include <spot/twa/bddprint.hh>
-
 #include <spot/twaalgos/dot.hh>
-#include <spot/twaalgos/lbtt.hh>
 #include <spot/twaalgos/hoa.hh>
-#include <spot/twaalgos/neverclaim.hh>
-#include <spot/twaalgos/stutter.hh>
 #include <spot/twaalgos/isunamb.hh>
+#include <spot/twaalgos/lbtt.hh>
+#include <spot/twaalgos/neverclaim.hh>
 #include <spot/twaalgos/strength.hh>
+#include <spot/twaalgos/stutter.hh>
 
 automaton_format_t automaton_format = Hoa;
 static const char* automaton_format_opt = nullptr;
@@ -173,6 +172,11 @@ static const argp_option io_options[] =
       "using the following LETTERS, possibly concatenated: (a) accepting, "
       "(r) rejecting, (v) trivial, (t) terminal, (w) weak, "
       "(iw) inherently weak. Use uppercase letters to negate them.", 0 },
+    { "%R, %[LETTERS]R", 0, nullptr,
+      OPTION_DOC | OPTION_NO_USAGE,
+      "CPU time (excluding parsing), in seconds; Add LETTERS to restrict to"
+      "(u) user time, (s) system time or to omit (p) parent processes, "
+      "(c) children processes.", 0 },
     { "%N, %n", 0, nullptr, OPTION_DOC | OPTION_NO_USAGE,
       "number of nondeterministic states", 0 },
     { "%D, %d", 0, nullptr, OPTION_DOC | OPTION_NO_USAGE,
@@ -180,7 +184,7 @@ static const argp_option io_options[] =
     { "%P, %p", 0, nullptr, OPTION_DOC | OPTION_NO_USAGE,
       "1 if the automaton is complete, 0 otherwise", 0 },
     { "%r", 0, nullptr, OPTION_DOC | OPTION_NO_USAGE,
-      "processing time (excluding parsing) in seconds", 0 },
+      "wall-clock time elapsed in seconds (excluding parsing)", 0 },
     { "%W, %w", 0, nullptr, OPTION_DOC | OPTION_NO_USAGE,
       "one word accepted by the automaton", 0 },
     { "%%", 0, nullptr, OPTION_DOC | OPTION_NO_USAGE,
@@ -225,6 +229,11 @@ static const argp_option o_options[] =
       "using the following LETTERS, possibly concatenated: (a) accepting, "
       "(r) rejecting, (v) trivial, (t) terminal, (w) weak, "
       "(iw) inherently weak. Use uppercase letters to negate them.", 0 },
+    { "%R, %[LETTERS]R", 0, nullptr,
+      OPTION_DOC | OPTION_NO_USAGE,
+      "CPU time (excluding parsing), in seconds; Add LETTERS to restrict to"
+      "(u) user time, (s) system time or to omit (p) parent processes, "
+      "(c) children processes.", 0 },
     { "%n", 0, nullptr, OPTION_DOC | OPTION_NO_USAGE,
       "number of nondeterministic states in output", 0 },
     { "%d", 0, nullptr, OPTION_DOC | OPTION_NO_USAGE,
@@ -232,7 +241,7 @@ static const argp_option o_options[] =
     { "%p", 0, nullptr, OPTION_DOC | OPTION_NO_USAGE,
       "1 if the output is complete, 0 otherwise", 0 },
     { "%r", 0, nullptr, OPTION_DOC | OPTION_NO_USAGE,
-      "processing time (excluding parsing) in seconds", 0 },
+      "wall-clock time elapsed in seconds (excluding parsing)", 0 },
     { "%w", 0, nullptr, OPTION_DOC | OPTION_NO_USAGE,
       "one word accepted by the output automaton", 0 },
     { "%%", 0, nullptr, OPTION_DOC | OPTION_NO_USAGE,
@@ -351,6 +360,7 @@ hoa_stat_printer::hoa_stat_printer(std::ostream& os, const char* format,
   declare('>', &csv_suffix_);
   declare('F', &filename_);
   declare('L', &location_);
+  declare('R', &timer_);
   if (input != ltl_input)
     declare('f', &filename_);        // Override the formula printer.
   declare('h', &output_aut_);
@@ -362,9 +372,12 @@ std::ostream&
 hoa_stat_printer::print(const spot::const_parsed_aut_ptr& haut,
                         const spot::const_twa_graph_ptr& aut,
                         spot::formula f,
-                        const char* filename, int loc, double run_time,
+                        const char* filename, int loc, process_timer& ptimer,
                         const char* csv_prefix, const char* csv_suffix)
 {
+  timer_ = ptimer.dt;
+  double run_time = ptimer.get_lap_sw();
+
   filename_ = filename ? filename : "";
   csv_prefix_ = csv_prefix ? csv_prefix : "";
   csv_suffix_ = csv_suffix ? csv_suffix : "";
@@ -494,12 +507,13 @@ automaton_printer::automaton_printer(stat_style input)
 
 void
 automaton_printer::print(const spot::twa_graph_ptr& aut,
+                         // Time for statistics
+                         process_timer& ptimer,
                          spot::formula f,
                          // Input location for errors and statistics.
                          const char* filename,
                          int loc,
-                         // Time and input automaton for statistics
-                         double time,
+                         // input automaton for statistics
                          const spot::const_parsed_aut_ptr& haut,
                          const char* csv_prefix,
                          const char* csv_suffix)
@@ -518,7 +532,7 @@ automaton_printer::print(const spot::twa_graph_ptr& aut,
   if (opt_name)
     {
       name.str("");
-      namer.print(haut, aut, f, filename, loc, time, csv_prefix, csv_suffix);
+      namer.print(haut, aut, f, filename, loc, ptimer, csv_prefix, csv_suffix);
       aut->set_named_prop("automaton-name", new std::string(name.str()));
     }
 
@@ -526,7 +540,7 @@ automaton_printer::print(const spot::twa_graph_ptr& aut,
   if (opt_output)
     {
       outputname.str("");
-      outputnamer.print(haut, aut, f, filename, loc, time,
+      outputnamer.print(haut, aut, f, filename, loc, ptimer,
                         csv_prefix, csv_suffix);
       std::string fname = outputname.str();
       auto p = outputfiles.emplace(fname, nullptr);
@@ -556,7 +570,7 @@ automaton_printer::print(const spot::twa_graph_ptr& aut,
       break;
     case Stats:
       statistics.set_output(*out);
-      statistics.print(haut, aut, f, filename, loc, time,
+      statistics.print(haut, aut, f, filename, loc, ptimer,
                        csv_prefix, csv_suffix) << '\n';
       break;
     }
@@ -590,3 +604,70 @@ void printable_automaton::print(std::ostream& os, const char* pos) const
     }
   print_hoa(os, val_, options.c_str());
 }
+
+void printable_timer::print(std::ostream& os, const char* pos) const
+{
+  double res = 0;
+
+  if (*pos != '[')
+  {
+    res = val_.get_uscp(true, true, true, true);
+    os << res / sysconf(_SC_CLK_TCK);
+    return;
+  }
+
+  bool user = false;
+  bool system = false;
+  bool parent = false;
+  bool children = false;
+
+  const char* beg = pos;
+  auto error = [&](std::string str)
+  {
+    std::ostringstream tmp;
+    const char* end = std::strchr(pos, ']');
+    tmp << "unknown option '" << str << "' in '%" << std::string(beg, end + 2)
+      << '\'';
+    throw std::runtime_error(tmp.str());
+  };
+
+  do
+  {
+    ++pos;
+    switch (*pos)
+    {
+      case 'u':
+        user = true;
+        break;
+      case 's':
+        system = true;
+        break;
+      case 'p':
+        parent = true;
+        break;
+      case 'c':
+        children = true;
+        break;
+      case ' ':
+      case '\t':
+      case '\n':
+      case ',':
+      case ']':
+        break;
+      default:
+        error(std::string(pos, pos + 1));
+    }
+  } while (*pos != ']');
+
+  if (user && !parent && !children)
+    parent = children = true;
+  if (system && !parent && !children)
+    parent = children = true;
+  if (parent && !user && !system)
+    user = system = true;
+  if (children && !user && !system)
+    user = system = true;
+
+  res = val_.get_uscp(user, system, children, parent);
+  os << res / sysconf(_SC_CLK_TCK);
+}
diff --git a/bin/common_aoutput.hh b/bin/common_aoutput.hh
index 008fc9c09..9a10b0745 100644
--- a/bin/common_aoutput.hh
+++ b/bin/common_aoutput.hh
@@ -20,18 +20,17 @@
 #pragma once
 
 #include "common_sys.hh"
+#include "common_file.hh"
 
 #include <argp.h>
 #include <memory>
-
+#include <spot/misc/timer.hh>
 #include <spot/parseaut/public.hh>
-
-#include <spot/twaalgos/stats.hh>
-#include <spot/twaalgos/sccinfo.hh>
 #include <spot/twaalgos/gtec/gtec.hh>
-#include <spot/twaalgos/word.hh>
 #include <spot/twaalgos/isdet.hh>
-#include "common_file.hh"
+#include <spot/twaalgos/sccinfo.hh>
+#include <spot/twaalgos/stats.hh>
+#include <spot/twaalgos/word.hh>
 
 
 // Format for automaton output
@@ -74,6 +73,40 @@ struct printable_automaton final:
   void print(std::ostream& os, const char* pos) const override;
 };
 
+
+struct process_timer
+{
+  void start()
+  {
+    sw.start();
+    dt.start();
+  }
+
+  void stop()
+  {
+    // sw.stop() --> It always returns the duration since the last call to
+    // start(). Therefore, it wont't stop timing, moreover, it can be called
+    // multiple times.
+    sw_lap_ = sw.stop();
+    dt.stop();
+  }
+  double get_lap_sw()
+  {
+    return sw_lap_;
+  }
+
+  spot::timer dt;
+  spot::stopwatch sw;
+  double sw_lap_ = 0;
+};
+
+struct printable_timer final:
+  public spot::printable_value<spot::timer>
+{
+  using spot::printable_value<spot::timer>::operator=;
+  void print(std::ostream& os, const char* pos) const override;
+};
+
 /// \brief prints various statistics about a TGBA
 ///
 /// This object can be configured to display various statistics
@@ -83,7 +116,7 @@ class hoa_stat_printer: protected spot::stat_printer
 {
 public:
   hoa_stat_printer(std::ostream& os, const char* format,
-                   stat_style input = no_input);
+      stat_style input = no_input);
 
   using spot::formater::declare;
   using spot::formater::set_output;
@@ -93,10 +126,10 @@ public:
   /// The \a f argument is not needed if the Formula does not need
   /// to be output.
   std::ostream&
-  print(const spot::const_parsed_aut_ptr& haut,
+    print(const spot::const_parsed_aut_ptr& haut,
         const spot::const_twa_graph_ptr& aut,
         spot::formula f,
-        const char* filename, int loc, double run_time,
+        const char* filename, int loc, process_timer& ptimer,
         const char* csv_prefix, const char* csv_suffix);
 
 private:
@@ -117,6 +150,7 @@ private:
   spot::printable_value<unsigned> haut_complete_;
   spot::printable_value<const char*> csv_prefix_;
   spot::printable_value<const char*> csv_suffix_;
+  printable_timer timer_;
   printable_automaton input_aut_;
   printable_automaton output_aut_;
 };
@@ -132,18 +166,17 @@ class automaton_printer
   std::map<std::string, std::unique_ptr<output_file>> outputfiles;
 
 public:
-
   automaton_printer(stat_style input = no_input);
   ~automaton_printer();
 
   void
   print(const spot::twa_graph_ptr& aut,
+        process_timer& ptimer,
         spot::formula f = nullptr,
         // Input location for errors and statistics.
         const char* filename = nullptr,
         int loc = -1,
         // Time and input automaton for statistics
-        double time = 0.0,
         const spot::const_parsed_aut_ptr& haut = nullptr,
         const char* csv_prefix = nullptr,
         const char* csv_suffix = nullptr);
diff --git a/bin/dstar2tgba.cc b/bin/dstar2tgba.cc
index 7df42b64b..505e6b303 100644
--- a/bin/dstar2tgba.cc
+++ b/bin/dstar2tgba.cc
@@ -213,13 +213,12 @@ namespace
     process_automaton(const spot::const_parsed_aut_ptr& haut,
                       const char* filename)
     {
-      spot::stopwatch sw;
-      sw.start();
+      process_timer timer;
+      timer.start();
       auto nba = spot::to_generalized_buchi(haut->aut);
       auto aut = post.run(nba, nullptr);
-      const double conversion_time = sw.stop();
-
-      printer.print(aut, nullptr, filename, -1, conversion_time, haut);
+      timer.stop();
+      printer.print(aut, timer, nullptr, filename, -1, haut);
       flush_cout();
       return 0;
     }
diff --git a/bin/ltl2tgba.cc b/bin/ltl2tgba.cc
index d1c1992ab..41beae20d 100644
--- a/bin/ltl2tgba.cc
+++ b/bin/ltl2tgba.cc
@@ -139,12 +139,12 @@ namespace
                         s.c_str());
         }
 
-      spot::stopwatch sw;
-      sw.start();
+      process_timer timer;
+      timer.start();
       auto aut = trans.run(&f);
-      const double translation_time = sw.stop();
+      timer.stop();
 
-      printer.print(aut, f, filename, linenum, translation_time, nullptr,
+      printer.print(aut, timer, f, filename, linenum, nullptr,
                     prefix, suffix);
       return 0;
     }
diff --git a/bin/ltlcross.cc b/bin/ltlcross.cc
index fe171a284..f93804c56 100644
--- a/bin/ltlcross.cc
+++ b/bin/ltlcross.cc
@@ -39,6 +39,7 @@
 #include "common_file.hh"
 #include "common_finput.hh"
 #include "common_hoaread.hh"
+#include "common_aoutput.hh"
 #include <spot/parseaut/public.hh>
 #include <spot/tl/print.hh>
 #include <spot/tl/apcollect.hh>
@@ -534,11 +535,10 @@ namespace
       std::string cmd = command.str();
       std::cerr << "Running [" << l << translator_num << "]: "
                 << cmd << std::endl;
-      spot::stopwatch sw;
-      sw.start();
+      process_timer timer;
+      timer.start();
       int es = exec_with_timeout(cmd.c_str());
-      double duration = sw.stop();
-
+      timer.stop();
       const char* status_str = nullptr;
 
       spot::twa_graph_ptr res = nullptr;
@@ -619,7 +619,7 @@ namespace
           statistics* st = &(*fstats)[translator_num];
           st->status_str = status_str;
           st->status_code = es;
-          st->time = duration;
+          st->time = timer.get_lap_sw();
 
           // Compute statistics.
           if (res)
diff --git a/bin/ltldo.cc b/bin/ltldo.cc
index c9e69776f..81cc3da33 100644
--- a/bin/ltldo.cc
+++ b/bin/ltldo.cc
@@ -168,7 +168,7 @@ namespace
     }
 
     spot::twa_graph_ptr
-    translate(unsigned int translator_num, bool& problem, double& duration)
+    translate(unsigned int translator_num, bool& problem, process_timer& timer)
     {
       output.reset(translator_num);
 
@@ -178,10 +178,9 @@ namespace
       std::string cmd = command.str();
       //std::cerr << "Running [" << l << translator_num << "]: "
       // << cmd << std::endl;
-      spot::stopwatch sw;
-      sw.start();
+      timer.start();
       int es = exec_with_timeout(cmd.c_str());
-      duration = sw.stop();
+      timer.stop();
 
       spot::twa_graph_ptr res = nullptr;
       problem = false;
@@ -316,8 +315,8 @@ namespace
       for (unsigned t = 0; t < ts; ++t)
         {
           bool problem;
-          double translation_time;
-          auto aut = runner.translate(t, problem, translation_time);
+          process_timer timer;
+          auto aut = runner.translate(t, problem, timer);
           if (problem)
             {
               if (errors_opt == errors_abort)
@@ -333,7 +332,7 @@ namespace
               aut = post.run(aut, f);
               cmdname = translators[t].name;
               roundval = round;
-              printer.print(aut, f, filename, linenum, translation_time,
+              printer.print(aut, timer, f, filename, linenum,
                             nullptr, prefix, suffix);
             };
         }
diff --git a/bin/randaut.cc b/bin/randaut.cc
index ac65ac2e7..971f4664b 100644
--- a/bin/randaut.cc
+++ b/bin/randaut.cc
@@ -341,8 +341,8 @@ main(int argc, char** argv)
 
       for (;;)
         {
-          spot::stopwatch sw;
-          sw.start();
+          process_timer timer;
+          timer.start();
 
           if (ap_count_given.max > 0
               && ap_count_given.min != ap_count_given.max)
@@ -395,10 +395,10 @@ main(int argc, char** argv)
               trials = max_trials;
             }
 
-          auto runtime = sw.stop();
+          timer.stop();
 
-          printer.print(aut, nullptr,
-                        opt_seed_str, automaton_num, runtime, nullptr);
+          printer.print(aut, timer, nullptr,
+                        opt_seed_str, automaton_num, nullptr);
 
           ++automaton_num;
           if (opt_automata > 0 && automaton_num >= opt_automata)
diff --git a/spot/misc/formater.hh b/spot/misc/formater.hh
index d1edc985a..879cbebd0 100644
--- a/spot/misc/formater.hh
+++ b/spot/misc/formater.hh
@@ -20,10 +20,13 @@
 #pragma once
 
 #include <spot/misc/common.hh>
+#include <spot/misc/timer.hh>
 #include <iostream>
 #include <string>
 #include <vector>
 
+#define UNUSED(expr) do { (void)(expr); } while (0)
+
 namespace spot
 {
   class printable
@@ -85,6 +88,15 @@ namespace spot
     }
   };
 
+  // This function was defined to avoid compilation error when
+  // instantiating function spot::printable_value<spot::timer>::print
+  // because of: os << val_;
+  std::ostream& operator<<(std::ostream& os, const timer& dt)
+  {
+    UNUSED(dt);
+    return os;
+  }
+
   /// The default callback simply writes "%c".
   class printable_id: public printable
   {
diff --git a/spot/misc/timer.cc b/spot/misc/timer.cc
index e1e98c74d..649f59884 100644
--- a/spot/misc/timer.cc
+++ b/spot/misc/timer.cc
@@ -27,6 +27,15 @@
 
 namespace spot
 {
+  /*
+  std::ostream& operator<<(std::ostream& os, const timer& dt)
+  {
+    os << "utime<" << dt.utime() << ">, cutime<" << dt.cutime()
+      << ">, stime<" << dt.stime() << ">, cstime<" << dt.cstime() << '>';
+    return os;
+  }
+  */
+
 
   std::ostream&
   timer_map::print(std::ostream& os) const
@@ -39,8 +48,11 @@ namespace spot
       {
         total.utime += i->second.first.utime();
         total.stime += i->second.first.stime();
+        total.cutime += i->second.first.cutime();
+        total.cstime += i->second.first.cstime();
       }
-    clock_t grand_total = total.utime + total.stime;
+    clock_t grand_total = total.utime + total.cutime
+      + total.stime + total.cstime;
 
     os << std::setw(23) << ""
        << "|    user time   |    sys. time   |      total     |"
@@ -61,18 +73,21 @@ namespace spot
         const char* sep = t.is_running() ? "+|" : " |";
 
         os << std::setw(22) << name << sep
-           << std::setw(6) << t.utime() << ' '
+           << std::setw(6) << t.utime() + t.cutime() << ' '
            << std::setw(8) << (total.utime ?
-                               100.0 * t.utime() / total.utime : 0.)
+                               100.0 * (t.utime() + t.cutime())
+                               / (total.utime + total.cutime) : 0.)
            << sep
-           << std::setw(6) << t.stime() << ' '
+           << std::setw(6) << t.stime() + t.cstime() << ' '
            << std::setw(8) << (total.stime ?
-                               100.0 * t.stime() / total.stime : 0.)
+                               100.0 * (t.stime() +t.cstime())
+                               / (total.stime + total.cstime) : 0.)
            << sep
-           << std::setw(6) << t.utime() + t.stime() << ' '
+           << std::setw(6) << t.utime() + t.cutime() + t.stime()
+            + t.cstime() << ' '
            << std::setw(8) << (grand_total ?
-                               (100.0 * (t.utime() + t.stime()) /
-                                grand_total) : 0.)
+                               (100.0 * (t.utime() + t.cutime() + t.stime()
+                                         + t.cstime()) / grand_total) : 0.)
            << sep
            << std::setw(4) << i->second.second
            << std::endl;
@@ -80,10 +95,10 @@ namespace spot
     os << std::setw(79) << std::setfill('-') << "" << std::setfill(' ')
        << std::endl
        << std::setw(22) << "TOTAL" << " |"
-       << std::setw(6) << total.utime << ' '
+       << std::setw(6) << total.utime + total.cutime << ' '
        << std::setw(8) << 100.
        << " |"
-       << std::setw(6) << total.stime << ' '
+       << std::setw(6) << total.stime + total.cstime << ' '
        << std::setw(8) << 100.
        << " |"
        << std::setw(6) << grand_total << ' '
diff --git a/spot/misc/timer.hh b/spot/misc/timer.hh
index 107c8b846..9b933e0e2 100644
--- a/spot/misc/timer.hh
+++ b/spot/misc/timer.hh
@@ -66,19 +66,22 @@ namespace spot
     }
   };
 
-
   /// A structure to record elapsed time in clock ticks.
   struct time_info
   {
     time_info()
-      : utime(0), stime(0)
+      : utime(0), stime(0), cutime(0), cstime(0)
     {
     }
     clock_t utime;
     clock_t stime;
+    clock_t cutime;
+    clock_t cstime;
   };
 
-  /// A timekeeper that accumulate interval of time.
+  /// A timekeeper that accumulate interval of time in a more detailed way.
+  /// For instance, you can get the time spent with or without children
+  /// processes.
   class timer
   {
   public:
@@ -96,8 +99,10 @@ namespace spot
 #ifdef SPOT_HAVE_TIMES
       struct tms tmp;
       times(&tmp);
-      start_.utime = tmp.tms_utime + tmp.tms_cutime;
-      start_.stime = tmp.tms_stime + tmp.tms_cstime;
+      start_.utime = tmp.tms_utime;
+      start_.cutime = tmp.tms_cutime;
+      start_.stime = tmp.tms_stime;
+      start_.cstime = tmp.tms_cstime;
 #else
       start_.utime = clock();
 #endif
@@ -110,8 +115,10 @@ namespace spot
 #ifdef SPOT_HAVE_TIMES
       struct tms tmp;
       times(&tmp);
-      total_.utime += tmp.tms_utime + tmp.tms_cutime - start_.utime;
-      total_.stime += tmp.tms_stime + tmp.tms_cstime - start_.stime;
+      total_.utime += tmp.tms_utime - start_.utime;
+      total_.cutime += tmp.tms_cutime - start_.cutime;
+      total_.stime += tmp.tms_stime - start_.stime;
+      total_.cstime += tmp.tms_cstime - start_.cstime;
 #else
       total_.utime += clock() - start_.utime;
 #endif
@@ -119,7 +126,8 @@ namespace spot
       running = false;
     }
 
-    /// \brief Return the user time of all accumulated interval.
+    /// \brief Return the user time of the current process (without children)
+    /// of all accumulated interval.
     ///
     /// Any time interval that has been start()ed but not stop()ed
     /// will not be accounted for.
@@ -129,7 +137,18 @@ namespace spot
       return total_.utime;
     }
 
-    /// \brief Return the system time of all accumulated interval.
+    /// \brief Return the user time of children of all accumulated interval.
+    ///
+    /// Any time interval that has been start()ed but not stop()ed
+    /// will not be accounted for.
+    clock_t
+    cutime() const
+    {
+      return total_.cutime;
+    }
+
+    /// \brief Return the system time of the current process (whithout children)
+    /// of all accumulated interval.
     ///
     /// Any time interval that has been start()ed but not stop()ed
     /// will not be accounted for.
@@ -139,6 +158,34 @@ namespace spot
       return total_.stime;
     }
 
+    /// \brief Return the system time of children of all accumulated interval.
+    ///
+    /// Any time interval that has been start()ed but not stop()ed
+    /// will not be accounted for.
+    clock_t
+    cstime() const
+    {
+      return total_.cstime;
+    }
+
+    clock_t get_uscp(bool user, bool system, bool children, bool parent) const
+    {
+      clock_t res = 0;
+
+      if (user && parent)
+        res += utime();
+
+      if (user && children)
+        res += cutime();
+
+      if (system && parent)
+        res += stime();
+
+      if (system && children)
+        res += cstime();
+
+      return res;
+    }
 
     /// \brief Whether the timer is running.
     bool
@@ -153,6 +200,10 @@ namespace spot
     bool running;
   };
 
+  // This function declared here must be implemented in each file
+  // that includes this header, well, only if this operator is needed!
+  inline std::ostream& operator<<(std::ostream& os, const timer& dt);
+
   /// \brief A map of timer, where each timer has a name.
   ///
   /// Timer_map also keeps track of the number of measures each timer
diff --git a/spot/twaalgos/dtbasat.cc b/spot/twaalgos/dtbasat.cc
index 70036eff5..0f250fa9c 100644
--- a/spot/twaalgos/dtbasat.cc
+++ b/spot/twaalgos/dtbasat.cc
@@ -794,8 +794,10 @@ namespace spot
           }
         out << ','
             << s.first << ',' << s.second << ','
-            << te.utime() << ',' << te.stime() << ','
-            << ts.utime() << ',' << ts.stime() << '\n';
+            << te.utime() + te.cutime() << ','
+            << te.stime() + te.cstime() << ','
+            << ts.utime() + ts.cutime() << ','
+            << ts.stime() + ts.cstime() << '\n';
       }
     static bool show = getenv("SPOT_SATSHOW");
     if (show && res)
diff --git a/spot/twaalgos/dtwasat.cc b/spot/twaalgos/dtwasat.cc
index 6da958dae..c9b01f236 100644
--- a/spot/twaalgos/dtwasat.cc
+++ b/spot/twaalgos/dtwasat.cc
@@ -1173,8 +1173,10 @@ namespace spot
           }
         out << ','
             << s.first << ',' << s.second << ','
-            << te.utime() << ',' << te.stime() << ','
-            << ts.utime() << ',' << ts.stime() << '\n';
+            << te.utime() + te.cutime() << ','
+            << te.stime() + te.cstime() << ','
+            << ts.utime() + ts.cutime() << ','
+            << ts.stime() + ts.cstime() << '\n';
       }
     static bool show = getenv("SPOT_SATSHOW");
     if (show && res)