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     close_received = false;
  43     may_receive =  (neigh.size() > 0); // the same as (ctrl_close_pending ||
  44                                        //              data_close_pending)
  45     finalizing = false;
  46
  47     e_xbt_log_priority_t logp = xbt_log_priority_verbose;
  48     if (!LOG_ISENABLED(logp))
  49         return;
  50     std::ostringstream oss;
  51     oss << neigh.size() << " neighbor";
  52     if (!neigh.empty()) {
  53         oss << ESSE(neigh.size()) << ": ";
  54         std::transform(neigh.begin(), neigh.end() - 1,
  55                        std::ostream_iterator<const char*>(oss, ", "),
  56                        std::tr1::mem_fn(&neighbor::get_name));
  57         oss << neigh.back().get_name();
  58     }
  59     LOG1(logp, "Got %s.", oss.str().c_str());
  60     print_loads(false, logp);
  61 }
  62
  63 process::~process()
  64 {
  65     total_load_exit += load;
  66 }
  67
  68 int process::run()
  69 {
  70     INFO1("Initial load: %g", load);
  71     VERB0("Starting...");
  72     comp_iter = lb_iter = 0;
  73     while (true) {
  74         if (load > 0.0) {
  75             ++comp_iter;
  76             if (opt::log_rate && comp_iter % opt::log_rate == 0) {
  77                 if (opt::bookkeeping)
  78                     INFO4("(%u:%u) current load: %g ; expected: %g",
  79                           comp_iter, lb_iter, load, expected_load);
  80                 else
  81                     INFO2("(%u) current load: %g",
  82                           comp_iter, load);
  83             }
  84
  85             if (opt::bookkeeping)
  86                 expected_load -= load_balance(expected_load);
  87             else
  88                 load -= load_balance(load);
  89
  90             print_loads(true, xbt_log_priority_debug);
  91
  92             send();
  93             compute();
  94
  95         } else {
  96             // send load information, and load when bookkeeping
  97             send();
  98         }
  99
 100         if (opt::comp_maxiter && comp_iter >= opt::comp_maxiter)
 101             break;
 102         if (opt::lb_maxiter && lb_iter >= opt::lb_maxiter)
 103             break;
 104
 105         // block on receiving unless there is something to compute or
 106         // to send
 107         bool recv_wait = (load == 0 &&
 108                           ((opt::bookkeeping ? expected_load : load)
 109                            == prev_load_broadcast));
 110         receive(recv_wait? WAIT: NO_WAIT);
 111
 112         // one of our neighbor is finalizing
 113         if (opt::exit_on_close && close_received)
 114             break;
 115
 116         // have no load and cannot receive anything
 117         if (load == 0.0 && !may_receive)
 118             break;
 119
 120         // fixme: this check should be implemented with a distributed
 121         // algorithm, and not a shared global variable!
 122         // fixme: should this chunk be moved before call to receive() ?
 123         if (100.0 * total_load_running / total_load_init <=
 124             opt::load_ratio_threshold) {
 125             VERB0("No more load to balance in system, stopping.");
 126             break;
 127         }
 128
 129     }
 130     VERB0("Going to finalize...");
 131     finalize();
 132
 133     /* Open Questions :
 134      * - definition of load on heterogeneous hosts ?
 135      * - how to detect convergence ?
 136      * - how to manage link failures ?
 137      */
 138
 139     VERB0("Done.");
 140     INFO3("Final load after %d iteration%s: %g",
 141           comp_iter, ESSE(comp_iter), load);
 142     if (opt::bookkeeping)
 143         INFO1("Expected load: %g", expected_load);
 144     return 0;
 145 }
 146
 147 double process::sum_of_to_send() const
 148 {
 149     using std::tr1::bind;
 150     using std::tr1::placeholders::_1;
 151     using std::tr1::placeholders::_2;
 152
 153     return std::accumulate(neigh.begin(), neigh.end(), 0.0,
 154                            bind(std::plus<double>(),
 155                                 _1, bind(&neighbor::get_to_send, _2)));
 156 }
 157
 158 double process::load_balance(double /*my_load*/)
 159 {
 160     if (lb_iter == 1)           // warn only once
 161         WARN0("process::load_balance is a no-op!");
 162     return 0.0;
 163 }
 164
 165 void process::compute()
 166 {
 167     if (load > 0.0) {
 168         double duration = opt::comp_cost(load);
 169         m_task_t task = MSG_task_create("computation", duration, 0.0, NULL);
 170         DEBUG2("compute %g flop%s", duration, ESSE(duration));
 171         MSG_task_execute(task);
 172         MSG_task_destroy(task);
 173     } else {
 174         DEBUG0("nothing to compute !");
 175     }
 176 }
 177
 178 void process::send1_no_bookkeeping(neighbor& nb)
 179 {
 180     if (load != prev_load_broadcast)
 181         comm.send(nb.get_ctrl_mbox(), new message(message::INFO, load));
 182     double load_to_send = nb.get_to_send();
 183     if (load_to_send > 0.0) {
 184         comm.send(nb.get_data_mbox(), new message(message::LOAD, load_to_send));
 185         nb.set_to_send(0.0);
 186     }
 187 }
 188
 189 void process::send1_bookkeeping(neighbor& nb)
 190 {
 191     if (expected_load != prev_load_broadcast)
 192         comm.send(nb.get_ctrl_mbox(),
 193                   new message(message::INFO, expected_load));
 194     double load_to_send;
 195     double new_debt;
 196     double debt_to_send = nb.get_to_send();
 197     if (debt_to_send > 0.0) {
 198         comm.send(nb.get_ctrl_mbox(),
 199                   new message(message::CREDIT, debt_to_send));
 200         nb.set_to_send(0.0);
 201         new_debt = nb.get_debt() + debt_to_send;
 202     } else {
 203         new_debt = nb.get_debt();
 204     }
 205     if (load <= new_debt) {
 206         load_to_send = load;
 207         nb.set_debt(new_debt - load_to_send);
 208         load = 0.0;
 209     } else {
 210         load_to_send = new_debt;
 211         nb.set_debt(0.0);
 212         load -= load_to_send;
 213     }
 214     if (load_to_send > 0.0)
 215         comm.send(nb.get_data_mbox(), new message(message::LOAD, load_to_send));
 216 }
 217
 218 void process::send()
 219 {
 220     using std::tr1::bind;
 221     using std::tr1::placeholders::_1;
 222
 223     if (opt::bookkeeping) {
 224         std::for_each(neigh.begin(), neigh.end(),
 225                       bind(&process::send1_bookkeeping, this, _1));
 226         prev_load_broadcast = expected_load;
 227     } else {
 228         std::for_each(neigh.begin(), neigh.end(),
 229                       bind(&process::send1_no_bookkeeping, this, _1));
 230         prev_load_broadcast = load;
 231     }
 232 }
 233
 234 void process::receive(recv_wait_mode wait)
 235 {
 236     message* msg;
 237     m_host_t from;
 238
 239     DEBUG1("go for receive(%s)",
 240            "NO_WAIT\0WAIT\0\0\0\0WAIT_FOR_CLOSE" + 8 * wait);
 241
 242     bool do_wait = (wait != NO_WAIT);
 243     while (may_receive && comm.recv(msg, from, do_wait)) {
 244         switch (msg->get_type()) {
 245         case message::INFO: {
 246             neighbor* n = rev_neigh[from];
 247             n->set_load(msg->get_amount());
 248             break;
 249         }
 250         case message::CREDIT:
 251             expected_load += msg->get_amount();
 252             break;
 253         case message::LOAD: {
 254             double ld = msg->get_amount();
 255             load += ld;
 256             if (finalizing)
 257                 total_load_running -= ld;
 258             break;
 259         }
 260         case message::CTRL_CLOSE:
 261             ctrl_close_pending--;
 262             DEBUG1("ctrl_close_pending = %d", ctrl_close_pending);
 263             close_received = true;
 264             break;
 265         case message::DATA_CLOSE:
 266             data_close_pending--;
 267             DEBUG1("data_close_pending = %d", data_close_pending);
 268             close_received = true;
 269             break;
 270         }
 271         delete msg;
 272         may_receive = (ctrl_close_pending || data_close_pending);
 273         do_wait = (wait == WAIT_FOR_CLOSE);
 274     }
 275 }
 276
 277 void process::finalize1(neighbor& nb)
 278 {
 279     comm.send(nb.get_ctrl_mbox(), new message(message::CTRL_CLOSE, 0.0));
 280     comm.send(nb.get_data_mbox(), new message(message::DATA_CLOSE, 0.0));
 281 }
 282
 283 void process::finalize()
 284 {
 285     using std::tr1::bind;
 286     using std::tr1::placeholders::_1;
 287
 288     finalizing = true;
 289     total_load_running -= load;
 290
 291     DEBUG2("send CLOSE to %lu neighbor%s",
 292            (unsigned long )neigh.size(), ESSE(neigh.size()));
 293     std::for_each(neigh.begin(), neigh.end(),
 294                   bind(&process::finalize1, this, _1));
 295
 296     DEBUG2("wait for CLOSE from %lu neighbor%s",
 297            (unsigned long )neigh.size(), ESSE(neigh.size()));
 298     receive(WAIT_FOR_CLOSE);
 299
 300     comm.flush(true);
 301 }
 302
 303 #define print_loads_generic(vec, verbose, logp, cat)                    \
 304     if (_XBT_LOG_ISENABLEDV((*cat), logp)) {                            \
 305         using std::tr1::bind;                                           \
 306         using std::tr1::placeholders::_1;                               \
 307         XCLOG0(cat, logp, "Neighbor loads:");                           \
 308         std::for_each(vec.begin(), vec.end(),                           \
 309                       bind(&neighbor::print, _1, verbose, logp, cat));  \
 310     } else ((void)0)
 311
 312 void process::print_loads(bool verbose,
 313                           e_xbt_log_priority_t logp,
 314                           xbt_log_category_t cat) const
 315 {
 316     print_loads_generic(neigh, verbose, logp, cat);
 317 }
 318
 319 void process::print_loads_p(bool verbose,
 320                             e_xbt_log_priority_t logp,
 321                             xbt_log_category_t cat) const
 322 {
 323     print_loads_generic(pneigh, verbose, logp, cat);
 324 }
 325
 326 #undef print_loads_generic
 327
 328 // Local variables:
 329 // mode: c++
 330 // End: