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 #include "tracing.h"
  15
  16 #include "process.h"
  17
  18 double process::total_load_init = 0.0;
  19 double process::total_load_running = 0.0;
  20 double process::total_load_exit = 0.0;
  21
  22 process::process(int argc, char* argv[])
  23 {
  24     if (argc < 2 || !(std::istringstream(argv[1]) >> load))
  25         throw std::invalid_argument("bad or missing initial load parameter");
  26
  27     neigh.assign(argv + 2, argv + argc);
  28
  29     pneigh.reserve(neigh.size());
  30     for (unsigned i = 0 ; i < neigh.size() ; i++) {
  31         neighbor* ptr = &neigh[i];
  32         m_host_t host = MSG_get_host_by_name(ptr->get_name());
  33         pneigh.push_back(ptr);
  34         rev_neigh.insert(std::make_pair(host, ptr));
  35     }
  36
  37     comp = 0.0;
  38
  39     prev_load_broadcast = -1;   // force sending of load on first send_all()
  40     expected_load = load;
  41     total_load_running += load;
  42     total_load_init += load;
  43
  44     ctrl_close_pending = data_close_pending = neigh.size();
  45     close_received = false;
  46     finalizing = false;
  47
  48     e_xbt_log_priority_t logp = xbt_log_priority_verbose;
  49     if (!LOG_ISENABLED(logp))
  50         return;
  51     std::ostringstream oss;
  52     oss << neigh.size() << " neighbor";
  53     if (!neigh.empty()) {
  54         oss << ESSE(neigh.size()) << ": ";
  55         std::transform(neigh.begin(), neigh.end() - 1,
  56                        std::ostream_iterator<const char*>(oss, ", "),
  57                        std::tr1::mem_fn(&neighbor::get_name));
  58         oss << neigh.back().get_name();
  59     }
  60     LOG1(logp, "Got %s.", oss.str().c_str());
  61     print_loads(false, logp);
  62 }
  63
  64 process::~process()
  65 {
  66     total_load_exit += load;
  67     if (opt::bookkeeping) {
  68         INFO4("Final load after %d:%d iterations: %g ; expected: %g",
  69               lb_iter, comp_iter, load, expected_load);
  70     } else {
  71         INFO2("Final load after %d iterations: %g",
  72               lb_iter, load);
  73         if (lb_iter != comp_iter)
  74             WARN2("lb_iter (%d) and comp_iter (%d) differ!",
  75                   lb_iter, comp_iter);
  76     }
  77     VERB1("Total computation for this process: %g", comp);
  78 }
  79
  80 int process::run()
  81 {
  82     double next_iter_after_date = 0.0;
  83     INFO1("Initial load: %g", load);
  84     VERB0("Starting...");
  85     comp_iter = lb_iter = 0;
  86     while (true) {
  87         double ld = lb_load();
  88         if (ld > 0.0) {
  89             double now = MSG_get_clock();
  90             if (now < next_iter_after_date)
  91                 MSG_process_sleep(next_iter_after_date - now);
  92             next_iter_after_date = MSG_get_clock() + opt::min_iter_duration;
  93
  94             ++lb_iter;
  95
  96             if (opt::log_rate && lb_iter % opt::log_rate == 0) {
  97                 if (opt::bookkeeping)
  98                     INFO4("(%u:%u) current load: %g ; expected: %g",
  99                           lb_iter, comp_iter, load, expected_load);
 100                 else
 101                     INFO2("(%u) current load: %g",
 102                           lb_iter, load);
 103             }
 104
 105             ld -= load_balance(ld);
 106
 107             print_loads(true, xbt_log_priority_debug);
 108         }
 109         lb_load() = ld;
 110
 111         // send load information, and load (data) if any
 112         send_all();
 113         if (load > 0.0) {
 114             ++comp_iter;
 115             compute();
 116         }
 117
 118         if (opt::lb_maxiter && lb_iter >= opt::lb_maxiter) {
 119             VERB2("Reached lb_maxiter: %d/%d", lb_iter, opt::lb_maxiter);
 120             break;
 121         }
 122         if (opt::comp_maxiter && comp_iter >= opt::comp_maxiter) {
 123             VERB2("Reached comp_maxiter: %d/%d", comp_iter, opt::comp_maxiter);
 124             break;
 125         }
 126         if (opt::time_limit && MSG_get_clock() >= opt::time_limit) {
 127             VERB2("Reached time limit: %g/%g", MSG_get_clock(), opt::time_limit);
 128             break;
 129         }
 130
 131         // block on receiving unless there is something to compute or
 132         // to send
 133         double timeout;
 134         if (load != 0 || lb_load() != prev_load_broadcast)
 135             timeout = 0.0;
 136         else if (opt::min_iter_duration)
 137             timeout = opt::min_iter_duration;
 138         else
 139             timeout = 1.0;
 140         receive(timeout);
 141
 142         // one of our neighbor is finalizing
 143         if (opt::exit_on_close && close_received) {
 144             VERB0("Close received");
 145             break;
 146         }
 147
 148         // have no load and cannot receive anything
 149         if (load == 0.0 && !may_receive()) {
 150             VERB0("I'm a poor lonesome process, and I have no load...");
 151             break;
 152         }
 153
 154         // fixme: this check should be implemented with a distributed
 155         // algorithm, and not a shared global variable!
 156         // fixme: should this chunk be moved before call to receive() ?
 157         if (100.0 * total_load_running / total_load_init <=
 158             opt::load_ratio_threshold) {
 159             VERB0("No more load to balance in system.");
 160             break;
 161         } else {
 162             DEBUG1("still %g load to balance, continuing...", total_load_running);
 163         }
 164     }
 165     VERB0("Going to finalize...");
 166     finalize();
 167
 168     /* Open Questions :
 169      * - definition of load on heterogeneous hosts ?
 170      * - how to detect convergence ?
 171      * - how to manage link failures ?
 172      */
 173
 174     VERB0("Done.");
 175     return 0;
 176 }
 177
 178 double process::sum_of_to_send() const
 179 {
 180     using std::tr1::bind;
 181     using std::tr1::placeholders::_1;
 182     using std::tr1::placeholders::_2;
 183
 184     return std::accumulate(neigh.begin(), neigh.end(), 0.0,
 185                            bind(std::plus<double>(),
 186                                 _1, bind(&neighbor::get_to_send, _2)));
 187 }
 188
 189 double process::load_balance(double /*my_load*/)
 190 {
 191     if (lb_iter == 1)           // warn only once
 192         WARN0("process::load_balance() is a no-op!");
 193     return 0.0;
 194 }
 195
 196 void process::compute()
 197 {
 198     if (load > 0.0) {
 199         double flops = opt::comp_cost(load);
 200         m_task_t task = MSG_task_create("computation", flops, 0.0, NULL);
 201         TRACE_msg_set_task_category(task, TRACE_CAT_COMP);
 202         DEBUG2("compute %g flop%s", flops, ESSE(flops));
 203         MSG_task_execute(task);
 204         comp += flops;
 205         MSG_task_destroy(task);
 206     } else {
 207         DEBUG0("nothing to compute !");
 208     }
 209 }
 210
 211 void process::send1_no_bookkeeping(neighbor& nb)
 212 {
 213     if (load != prev_load_broadcast)
 214         comm.send(nb.get_ctrl_mbox(), new message(message::INFO, load));
 215     double load_to_send = nb.get_to_send();
 216     if (load_to_send > 0.0) {
 217         comm.send(nb.get_data_mbox(), new message(message::LOAD, load_to_send));
 218         nb.set_to_send(0.0);
 219     }
 220 }
 221
 222 void process::send1_bookkeeping(neighbor& nb)
 223 {
 224     if (expected_load != prev_load_broadcast)
 225         comm.send(nb.get_ctrl_mbox(),
 226                   new message(message::INFO, expected_load));
 227     double load_to_send;
 228     double new_debt;
 229     double debt_to_send = nb.get_to_send();
 230     if (debt_to_send > 0.0) {
 231         comm.send(nb.get_ctrl_mbox(),
 232                   new message(message::CREDIT, debt_to_send));
 233         nb.set_to_send(0.0);
 234         new_debt = nb.get_debt() + debt_to_send;
 235     } else {
 236         new_debt = nb.get_debt();
 237     }
 238     if (load <= new_debt) {
 239         load_to_send = load;
 240         nb.set_debt(new_debt - load_to_send);
 241         load = 0.0;
 242     } else {
 243         load_to_send = new_debt;
 244         nb.set_debt(0.0);
 245         load -= load_to_send;
 246     }
 247     if (load_to_send > 0.0)
 248         comm.send(nb.get_data_mbox(), new message(message::LOAD, load_to_send));
 249 }
 250
 251 void process::send_all()
 252 {
 253     using std::tr1::bind;
 254     using std::tr1::placeholders::_1;
 255
 256     if (opt::bookkeeping) {
 257         std::for_each(neigh.begin(), neigh.end(),
 258                       bind(&process::send1_bookkeeping, this, _1));
 259         prev_load_broadcast = expected_load;
 260     } else {
 261         std::for_each(neigh.begin(), neigh.end(),
 262                       bind(&process::send1_no_bookkeeping, this, _1));
 263         prev_load_broadcast = load;
 264     }
 265     comm.flush(false);
 266 }
 267
 268 void process::receive(double timeout)
 269 {
 270     message* msg;
 271     m_host_t from;
 272
 273     DEBUG2("%sblocking receive (%g)", "\0non-" + !timeout, timeout);
 274     while (may_receive() && comm.recv(msg, from, timeout)) {
 275         switch (msg->get_type()) {
 276         case message::INFO: {
 277             neighbor* n = rev_neigh[from];
 278             n->set_load(msg->get_amount());
 279             break;
 280         }
 281         case message::CREDIT:
 282             expected_load += msg->get_amount();
 283             break;
 284         case message::LOAD: {
 285             double ld = msg->get_amount();
 286             load += ld;
 287             if (finalizing)
 288                 total_load_running -= ld;
 289             break;
 290         }
 291         case message::CTRL_CLOSE:
 292             ctrl_close_pending--;
 293             close_received = true;
 294             break;
 295         case message::DATA_CLOSE:
 296             data_close_pending--;
 297             close_received = true;
 298             break;
 299         }
 300         delete msg;
 301         timeout = 0.0;          // only wait on first recv
 302     }
 303     comm.flush(false);
 304 }
 305
 306 void process::finalize1(neighbor& nb)
 307 {
 308     comm.send(nb.get_ctrl_mbox(), new message(message::CTRL_CLOSE, 0.0));
 309     comm.send(nb.get_data_mbox(), new message(message::DATA_CLOSE, 0.0));
 310 }
 311
 312 void process::finalize()
 313 {
 314     using std::tr1::bind;
 315     using std::tr1::placeholders::_1;
 316
 317     finalizing = true;
 318     total_load_running -= load;
 319
 320     DEBUG2("send CLOSE to %lu neighbor%s",
 321            (unsigned long )neigh.size(), ESSE(neigh.size()));
 322     std::for_each(neigh.begin(), neigh.end(),
 323                   bind(&process::finalize1, this, _1));
 324
 325     DEBUG2("wait for CLOSE from %lu neighbor%s",
 326            (unsigned long )neigh.size(), ESSE(neigh.size()));
 327     while (may_receive()) {
 328         comm.flush(false);
 329         receive(-1.0);
 330     }
 331
 332     comm.flush(true);
 333 }
 334
 335 #define print_loads_generic(vec, verbose, logp, cat)                    \
 336     if (_XBT_LOG_ISENABLEDV((*cat), logp)) {                            \
 337         using std::tr1::bind;                                           \
 338         using std::tr1::placeholders::_1;                               \
 339         XCLOG0(cat, logp, "Neighbor loads:");                           \
 340         std::for_each(vec.begin(), vec.end(),                           \
 341                       bind(&neighbor::print, _1, verbose, logp, cat));  \
 342     } else ((void)0)
 343
 344 void process::print_loads(bool verbose,
 345                           e_xbt_log_priority_t logp,
 346                           xbt_log_category_t cat) const
 347 {
 348     print_loads_generic(neigh, verbose, logp, cat);
 349 }
 350
 351 void process::print_loads_p(bool verbose,
 352                             e_xbt_log_priority_t logp,
 353                             xbt_log_category_t cat) const
 354 {
 355     print_loads_generic(pneigh, verbose, logp, cat);
 356 }
 357
 358 #undef print_loads_generic
 359
 360 // Local variables:
 361 // mode: c++
 362 // End: