process.cpp

   1 #include <algorithm>
   2 #include <tr1/functional>
   3 #include <iterator>
   4 #include <numeric>
   5 #include <stdexcept>
   6 #include <sstream>
   7 #include <xbt/log.h>
   8 #include <xbt/time.h>
   9
  10 XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(proc);
  11
  12 #include "misc.h"
  13 #include "options.h"
  14
  15 #include "process.h"
  16
  17 double process::total_load_init = 0.0;
  18 double process::total_load_running = 0.0;
  19 double process::total_load_exit = 0.0;
  20
  21 process::process(int argc, char* argv[])
  22 {
  23     if (argc < 2 || !(std::istringstream(argv[1]) >> load))
  24         throw std::invalid_argument("bad or missing initial load parameter");
  25
  26     neigh.assign(argv + 2, argv + argc);
  27
  28     pneigh.reserve(neigh.size());
  29     for (unsigned i = 0 ; i < neigh.size() ; i++) {
  30         neighbor* ptr = &neigh[i];
  31         m_host_t host = MSG_get_host_by_name(ptr->get_name());
  32         pneigh.push_back(ptr);
  33         rev_neigh.insert(std::make_pair(host, ptr));
  34     }
  35
  36     prev_load_broadcast = -1;   // force sending of load on first send()
  37     expected_load = load;
  38     total_load_running += load;
  39     total_load_init += load;
  40
  41     ctrl_close_pending = data_close_pending = neigh.size();
  42     if (neigh.size() == 1) {
  43         comm.next_close_on_ctrl_is_last();
  44         comm.next_close_on_data_is_last();
  45     }
  46     close_received = false;
  47     may_receive =  (neigh.size() > 0); // the same as (ctrl_close_pending ||
  48                                        //              data_close_pending)
  49     finalizing = false;
  50     if (may_receive)
  51         comm.listen();
  52
  53     e_xbt_log_priority_t logp = xbt_log_priority_verbose;
  54     if (!LOG_ISENABLED(logp))
  55         return;
  56     std::ostringstream oss;
  57     oss << neigh.size() << " neighbor";
  58     if (!neigh.empty()) {
  59         oss << ESSE(neigh.size()) << ": ";
  60         std::transform(neigh.begin(), neigh.end() - 1,
  61                        std::ostream_iterator<const char*>(oss, ", "),
  62                        std::tr1::mem_fn(&neighbor::get_name));
  63         oss << neigh.back().get_name();
  64     }
  65     LOG1(logp, "Got %s.", oss.str().c_str());
  66     print_loads(false, logp);
  67 }
  68
  69 process::~process()
  70 {
  71     total_load_exit += load;
  72 }
  73
  74 int process::run()
  75 {
  76     INFO1("Initial load: %g", load);
  77     VERB0("Starting...");
  78     iter = 0;
  79     while (true) {
  80         if (load > 0.0) {
  81             ++iter;
  82             if (opt::log_rate && iter % opt::log_rate == 0) {
  83                 if (opt::bookkeeping)
  84                     INFO3("(%u) current load: %g ; expected: %g",
  85                           iter, load, expected_load);
  86                 else
  87                     INFO2("(%u) current load: %g",
  88                           iter, load);
  89             }
  90
  91             if (opt::bookkeeping)
  92                 expected_load -= load_balance(expected_load);
  93             else
  94                 load -= load_balance(load);
  95
  96             print_loads(true, xbt_log_priority_debug);
  97
  98             send();
  99             compute();
 100
 101             if (opt::maxiter && iter >= opt::maxiter)
 102                 break;
 103         } else {
 104             // send load information, and load when bookkeeping
 105             send();
 106         }
 107
 108         // block on receiving unless there is something to compute or
 109         // to send
 110         bool recv_wait = (load == 0 &&
 111                           ((opt::bookkeeping ? expected_load : load)
 112                            == prev_load_broadcast));
 113         DEBUG1("CALL RECEIVE(%s)", recv_wait? "WAIT": "NO_WAIT");
 114         receive(recv_wait? WAIT: NO_WAIT);
 115
 116         // one of our neighbor is finalizing
 117         if (opt::exit_on_close && close_received)
 118             break;
 119
 120         // have no load and cannot receive anything
 121         if (load == 0.0 && !may_receive)
 122             break;
 123
 124         // fixme: this check should be implemented with a distributed
 125         // algorithm, and not a shared global variable!
 126         if (100.0 * total_load_running / total_load_init <=
 127             opt::load_ratio_threshold) {
 128             VERB0("No more load to balance in system, stopping.");
 129             break;
 130         }
 131
 132     }
 133     VERB0("Going to finalize...");
 134     finalize();
 135
 136     /* Open Questions :
 137      * - definition of load on heterogeneous hosts ?
 138      * - how to detect convergence ?
 139      * - how to manage link failures ?
 140      */
 141
 142     VERB0("Done.");
 143     INFO3("Final load after %d iteration%s: %g", iter, ESSE(iter), load);
 144     if (opt::bookkeeping)
 145         INFO1("Expected load: %g", expected_load);
 146     return 0;
 147 }
 148
 149 double process::sum_of_to_send() const
 150 {
 151     using namespace std::tr1;
 152     using namespace std::tr1::placeholders;
 153
 154     return std::accumulate(neigh.begin(), neigh.end(), 0.0,
 155                            bind(std::plus<double>(),
 156                                 _1, bind(&neighbor::get_to_send, _2)));
 157 }
 158
 159 double process::load_balance(double /*my_load*/)
 160 {
 161     if (iter == 1)
 162         WARN0("process::load_balance is a no-op!");
 163     return 0.0;
 164 }
 165
 166 void process::compute()
 167 {
 168     if (load > 0.0) {
 169         double duration = opt::comp_cost(load);
 170         m_task_t task = MSG_task_create("computation", duration, 0.0, NULL);
 171         DEBUG2("compute %g flop%s.", duration, ESSE(duration));
 172         MSG_task_execute(task);
 173         MSG_task_destroy(task);
 174     } else {
 175         DEBUG0("nothing to compute !");
 176     }
 177 }
 178
 179 void process::send1_no_bookkeeping(neighbor& nb)
 180 {
 181     if (load != prev_load_broadcast)
 182         comm.send(nb.get_ctrl_mbox(), new message(message::INFO, load));
 183     double load_to_send = nb.get_to_send();
 184     if (load_to_send > 0.0) {
 185         comm.send(nb.get_data_mbox(), new message(message::LOAD, load_to_send));
 186         nb.set_to_send(0.0);
 187     }
 188 }
 189
 190 void process::send1_bookkeeping(neighbor& nb)
 191 {
 192     if (expected_load != prev_load_broadcast)
 193         comm.send(nb.get_ctrl_mbox(),
 194                   new message(message::INFO, expected_load));
 195     double load_to_send;
 196     double new_debt;
 197     double debt_to_send = nb.get_to_send();
 198     if (debt_to_send > 0.0) {
 199         comm.send(nb.get_ctrl_mbox(),
 200                   new message(message::CREDIT, debt_to_send));
 201         nb.set_to_send(0.0);
 202         new_debt = nb.get_debt() + debt_to_send;
 203     } else {
 204         new_debt = nb.get_debt();
 205     }
 206     if (load <= new_debt) {
 207         load_to_send = load;
 208         nb.set_debt(new_debt - load_to_send);
 209         load = 0.0;
 210     } else {
 211         load_to_send = new_debt;
 212         nb.set_debt(0.0);
 213         load -= load_to_send;
 214     }
 215     if (load_to_send > 0.0)
 216         comm.send(nb.get_data_mbox(), new message(message::LOAD, load_to_send));
 217 }
 218
 219 void process::send()
 220 {
 221     using namespace std::tr1;
 222     using namespace std::tr1::placeholders;
 223
 224     if (opt::bookkeeping) {
 225         std::for_each(neigh.begin(), neigh.end(),
 226                       bind(&process::send1_bookkeeping, this, _1));
 227         prev_load_broadcast = expected_load;
 228     } else {
 229         std::for_each(neigh.begin(), neigh.end(),
 230                       bind(&process::send1_no_bookkeeping, this, _1));
 231         prev_load_broadcast = load;
 232     }
 233 }
 234
 235 void process::receive(recv_wait_mode wait)
 236 {
 237     // DEBUG1("go for receive(%s)",
 238     //        "NO_WAIT\0WAIT\0\0\0\0WAIT_FOR_CLOSE" + 8 * wait);
 239     message* msg;
 240     m_host_t from;
 241     bool do_wait = (wait != NO_WAIT);
 242     while (may_receive && comm.recv(msg, from, do_wait)) {
 243         switch (msg->get_type()) {
 244         case message::INFO: {
 245             neighbor* n = rev_neigh[from];
 246             n->set_load(msg->get_amount());
 247             break;
 248         }
 249         case message::CREDIT:
 250             expected_load += msg->get_amount();
 251             break;
 252         case message::LOAD: {
 253             double ld = msg->get_amount();
 254             load += ld;
 255             if (finalizing)
 256                 total_load_running -= ld;
 257             break;
 258         }
 259         case message::CTRL_CLOSE:
 260             if (--ctrl_close_pending == 1)
 261                 comm.next_close_on_ctrl_is_last();
 262             // DEBUG1("ctrl_close_pending = %d", ctrl_close_pending);
 263             close_received = true;
 264             break;
 265         case message::DATA_CLOSE:
 266             if (--data_close_pending == 1)
 267                 comm.next_close_on_data_is_last();
 268             // DEBUG1("data_close_pending = %d", data_close_pending);
 269             close_received = true;
 270             break;
 271         }
 272         delete msg;
 273         may_receive = (ctrl_close_pending || data_close_pending);
 274         do_wait = (wait == WAIT_FOR_CLOSE);
 275     }
 276 }
 277
 278 void process::finalize1(neighbor& nb)
 279 {
 280     comm.send(nb.get_ctrl_mbox(), new message(message::CTRL_CLOSE, 0.0));
 281     comm.send(nb.get_data_mbox(), new message(message::DATA_CLOSE, 0.0));
 282 }
 283
 284 void process::finalize()
 285 {
 286     using namespace std::tr1;
 287     using namespace std::tr1::placeholders;
 288
 289     finalizing = true;
 290     total_load_running -= load;
 291
 292     DEBUG2("send CLOSE to %d neighbor%s.",
 293            (int )neigh.size(), ESSE(neigh.size()));
 294     std::for_each(neigh.begin(), neigh.end(),
 295                   bind(&process::finalize1, this, _1));
 296
 297     DEBUG2("wait for CLOSE from %d neighbor%s.",
 298            (int )neigh.size(), ESSE(neigh.size()));
 299     receive(WAIT_FOR_CLOSE);
 300
 301     comm.flush(true);
 302 }
 303
 304 #define print_loads_generic(vec, verbose, logp, cat)                    \
 305     if (_XBT_LOG_ISENABLEDV((*cat), logp)) {                            \
 306         using namespace std::tr1;                                       \
 307         using namespace std::tr1::placeholders;                         \
 308         XCLOG0(cat, logp, "Neighbor loads:");                           \
 309         std::for_each(vec.begin(), vec.end(),                           \
 310                       bind(&neighbor::print, _1, verbose, logp, cat));  \
 311     } else ((void)0)
 312
 313 void process::print_loads(bool verbose,
 314                           e_xbt_log_priority_t logp,
 315                           xbt_log_category_t cat) const
 316 {
 317     print_loads_generic(neigh, verbose, logp, cat);
 318 }
 319
 320 void process::print_loads_p(bool verbose,
 321                             e_xbt_log_priority_t logp,
 322                             xbt_log_category_t cat) const
 323 {
 324     print_loads_generic(pneigh, verbose, logp, cat);
 325 }
 326
 327 #undef print_loads_generic
 328
 329 // Local variables:
 330 // mode: c++
 331 // End: