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