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 process::process(int argc, char* argv[])
  17 {
  18     if (argc < 2 || !(std::istringstream(argv[1]) >> load))
  19         throw std::invalid_argument("bad or missing initial load");
  20
  21     neigh.assign(argv + 2, argv + argc);
  22
  23     pneigh.reserve(neigh.size());
  24     for (unsigned i = 0 ; i < neigh.size() ; i++) {
  25         neighbor* ptr = &neigh[i];
  26         m_host_t host = MSG_get_host_by_name(ptr->get_name());
  27         pneigh.push_back(ptr);
  28         rev_neigh.insert(std::make_pair(host, ptr));
  29     }
  30
  31     expected_load = load;
  32
  33     ctrl_close_pending = data_close_pending = neigh.size();
  34     if (neigh.size() == 1) {
  35         comm.next_close_on_ctrl_is_last();
  36         comm.next_close_on_data_is_last();
  37     }
  38     if (neigh.size() > 0)
  39         comm.listen();
  40
  41     e_xbt_log_priority_t logp = xbt_log_priority_verbose;
  42     if (!LOG_ISENABLED(logp))
  43         return;
  44     std::ostringstream oss;
  45     oss << neigh.size() << " neighbor";
  46     if (!neigh.empty()) {
  47         oss << ESSE(neigh.size()) << ": ";
  48         std::transform(neigh.begin(), neigh.end() - 1,
  49                        std::ostream_iterator<const char*>(oss, ", "),
  50                        std::tr1::mem_fn(&neighbor::get_name));
  51         oss << neigh.back().get_name();
  52     }
  53     LOG1(logp, "Got %s.", oss.str().c_str());
  54     print_loads(logp);
  55 }
  56
  57 process::~process()
  58 {
  59 }
  60
  61 int process::run()
  62 {
  63     bool one_more = true;
  64
  65     INFO1("Initial load: %g", load);
  66     VERB0("Starting...");
  67     // first send() to inform neighbors about our load (force it)
  68     prev_load_broadcast = !(opt::bookkeeping? expected_load: load);
  69     send();
  70     iter = 0;
  71     while (one_more) {
  72         if (opt::log_rate && iter % opt::log_rate == 0) {
  73             if (opt::bookkeeping)
  74                 INFO3("(%u) current load: %g ; expected: %g",
  75                       iter, load, expected_load);
  76             else
  77                 INFO2("(%u) current load: %g",
  78                       iter, load);
  79         }
  80         print_loads(xbt_log_priority_debug);
  81
  82         bool do_compute = load > 0.0;
  83         if (do_compute) {
  84             compute();
  85             ++iter;
  86         }
  87
  88         bool close_received = !receive(do_compute? NO_WAIT: WAIT);
  89
  90         if (opt::bookkeeping)
  91             expected_load -= load_balance(expected_load);
  92         else
  93             load -= load_balance(load);
  94
  95         send();
  96
  97         if (opt::exit_on_close && close_received)
  98             one_more = false;
  99         if (opt::maxiter && iter >= opt::maxiter)
 100             one_more = false;
 101     }
 102     VERB0("Going to finalize...");
 103     finalize();
 104
 105     /* Open Questions :
 106      * - definition of load on heterogeneous hosts ?
 107      * - how to detect convergence ?
 108      * - how to manage link failures ?
 109      */
 110
 111     VERB0("Done.");
 112     if (opt::bookkeeping)
 113         INFO4("Final load after %d iteration%s: %g ; expected: %g",
 114               iter, ESSE(iter), load, expected_load);
 115     else
 116         INFO3("Final load after %d iteration%s: %g", iter, ESSE(iter), load);
 117     return 0;
 118 }
 119
 120 double process::sum_of_to_send() const
 121 {
 122     using namespace std::tr1;
 123     using namespace std::tr1::placeholders;
 124
 125     return std::accumulate(neigh.begin(), neigh.end(), 0.0,
 126                            bind(std::plus<double>(),
 127                                 _1, bind(&neighbor::get_to_send, _2)));
 128 }
 129
 130 double process::load_balance(double /*my_load*/)
 131 {
 132     return 0.0;
 133 }
 134
 135 void process::compute()
 136 {
 137     double duration = opt::comp_cost(load);
 138     m_task_t task = MSG_task_create("computation", duration, 0.0, NULL);
 139     DEBUG2("compute %g flop%s.", duration, ESSE(duration));
 140     MSG_task_execute(task);
 141     MSG_task_destroy(task);
 142 }
 143
 144 void process::send1_no_bookkeeping(neighbor& nb)
 145 {
 146     if (load != prev_load_broadcast)
 147         comm.send(nb.get_ctrl_mbox(), new message(message::INFO, load));
 148     double load_to_send = nb.get_to_send();
 149     if (load_to_send > 0.0) {
 150         comm.send(nb.get_data_mbox(), new message(message::LOAD, load_to_send));
 151         nb.set_to_send(0.0);
 152     }
 153 }
 154
 155 void process::send1_bookkeeping(neighbor& nb)
 156 {
 157     if (expected_load != prev_load_broadcast)
 158         comm.send(nb.get_ctrl_mbox(),
 159                   new message(message::INFO, expected_load));
 160     double load_to_send;
 161     double new_debt;
 162     double debt_to_send = nb.get_to_send();
 163     if (debt_to_send > 0.0) {
 164         comm.send(nb.get_ctrl_mbox(),
 165                   new message(message::CREDIT, debt_to_send));
 166         nb.set_to_send(0.0);
 167         new_debt = nb.get_debt() + debt_to_send;
 168     } else {
 169         new_debt = nb.get_debt();
 170     }
 171     if (load <= new_debt) {
 172         load_to_send = load;
 173         nb.set_debt(new_debt - load_to_send);
 174         load = 0.0;
 175     } else {
 176         load_to_send = new_debt;
 177         nb.set_debt(0.0);
 178         load -= load_to_send;
 179     }
 180     if (load_to_send > 0.0)
 181         comm.send(nb.get_data_mbox(), new message(message::LOAD, load_to_send));
 182 }
 183
 184 void process::send()
 185 {
 186     using namespace std::tr1;
 187     using namespace std::tr1::placeholders;
 188
 189     // fixme: shall we send data at all iterations?
 190     if (opt::bookkeeping) {
 191         std::for_each(neigh.begin(), neigh.end(),
 192                       bind(&process::send1_bookkeeping, this, _1));
 193         prev_load_broadcast = expected_load;
 194     } else {
 195         std::for_each(neigh.begin(), neigh.end(),
 196                       bind(&process::send1_no_bookkeeping, this, _1));
 197         prev_load_broadcast = load;
 198     }
 199 }
 200
 201 // Returns false if a CLOSE message was received.
 202 bool process::receive(recv_wait_mode wait)
 203 {
 204     bool result = true;
 205     message* msg;
 206     m_host_t from;
 207     bool do_recv = ctrl_close_pending || data_close_pending;
 208     while (do_recv && comm.recv(msg, from, wait)) {
 209         switch (msg->get_type()) {
 210         case message::INFO: {
 211             neighbor* n = rev_neigh[from];
 212             n->set_load(msg->get_amount());
 213             break;
 214         }
 215         case message::CREDIT:
 216             expected_load += msg->get_amount();
 217             break;
 218         case message::LOAD:
 219             load += msg->get_amount();
 220             break;
 221         case message::CTRL_CLOSE:
 222             if (--ctrl_close_pending == 1)
 223                 comm.next_close_on_ctrl_is_last();
 224             DEBUG1("ctrl_close_pending = %d", ctrl_close_pending);
 225             result = false;
 226             break;
 227         case message::DATA_CLOSE:
 228             if (--data_close_pending == 1)
 229                 comm.next_close_on_data_is_last();
 230             DEBUG1("data_close_pending = %d", data_close_pending);
 231             result = false;
 232             break;
 233         }
 234         delete msg;
 235         do_recv = (wait == WAIT_FOR_CLOSE) &&
 236             (ctrl_close_pending || data_close_pending);
 237     }
 238     return result;
 239 }
 240
 241 void process::finalize1(neighbor& nb)
 242 {
 243     comm.send(nb.get_ctrl_mbox(), new message(message::CTRL_CLOSE, 0.0));
 244     comm.send(nb.get_data_mbox(), new message(message::DATA_CLOSE, 0.0));
 245 }
 246
 247 void process::finalize()
 248 {
 249     using namespace std::tr1;
 250     using namespace std::tr1::placeholders;
 251
 252     DEBUG2("send CLOSE to %d neighbor%s.",
 253            (int )neigh.size(), ESSE(neigh.size()));
 254     std::for_each(neigh.begin(), neigh.end(),
 255                   bind(&process::finalize1, this, _1));
 256
 257     DEBUG2("wait for CLOSE from %d neighbor%s.",
 258            (int )neigh.size(), ESSE(neigh.size()));
 259     receive(WAIT_FOR_CLOSE);
 260
 261     comm.flush(true);
 262 }
 263
 264 void process::print_loads(e_xbt_log_priority_t logp)
 265 {
 266     if (!LOG_ISENABLED(logp))
 267         return;
 268
 269     std::ostringstream oss;
 270     if (neigh.empty()) {
 271         oss << "no neighbor!";
 272     } else {
 273         std::transform(neigh.begin(), neigh.end() - 1,
 274                        std::ostream_iterator<double>(oss, ", "),
 275                        std::tr1::mem_fn(&neighbor::get_load));
 276         oss << neigh.back().get_load();
 277     }
 278     LOG1(logp, "Neighbor loads: %s", oss.str().c_str());
 279 }
 280
 281 // Local variables:
 282 // mode: c++
 283 // End: