process.cpp

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