process.cpp

   1 #include <algorithm>
   2 #include <cmath>
   3 #include <functional>
   4 #include <iterator>
   5 #include <numeric>
   6 #include <stdexcept>
   7 #include <sstream>
   8 #include <xbt/log.h>
   9 #include <xbt/time.h>
  10
  11 XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(proc);
  12
  13 #include "misc.h"
  14 #include "options.h"
  15 #include "tracing.h"
  16
  17 #include "process.h"
  18
  19 double process::total_load_init = 0.0;
  20 double process::total_load_running = 0.0;
  21 double process::total_load_exit = 0.0;
  22
  23 int process::process_counter = 0;
  24 double process::total_load_average;
  25 double process::load_diff_threshold;
  26
  27 namespace {
  28
  29     void sleep_until_date(double& date, double duration)
  30     {
  31         double sleep_duration = date - MSG_get_clock();
  32         if (sleep_duration > 0.0)
  33             MSG_process_sleep(sleep_duration);
  34         date = MSG_get_clock() + duration;
  35     }
  36
  37 }
  38
  39 process::process(int argc, char* argv[])
  40 {
  41     if (argc < 2 || !(std::istringstream(argv[1]) >> real_load))
  42         throw std::invalid_argument("bad or missing initial load parameter");
  43
  44     double iload = std::trunc(real_load);
  45     if (opt::integer_transfer && real_load != iload) {
  46         XBT_WARN("Initial load %g is not an integer.  Truncate it.",
  47                  real_load);
  48         real_load = iload;
  49     }
  50
  51     neigh.assign(argv + 2, argv + argc);
  52
  53     pneigh.reserve(neigh.size());
  54     for (unsigned i = 0 ; i < neigh.size() ; i++) {
  55         neighbor* ptr = &neigh[i];
  56         m_host_t host = MSG_get_host_by_name(ptr->get_name());
  57         pneigh.push_back(ptr);
  58         rev_neigh.insert(std::make_pair(host, ptr));
  59     }
  60
  61     // Note: there should not be race condition with the current
  62     // version of Simgrid, when updating the global variables.
  63
  64     prev_load_broadcast = -1;   // force sending of load on first send_all()
  65     expected_load = real_load;
  66     total_load_running += real_load;
  67     total_load_init += real_load;
  68     received_load = 0.0;
  69
  70     idle_duration = 0.0;
  71     convergence = -1.0;
  72
  73     process_counter++;
  74     total_load_average = total_load_running / process_counter;
  75     load_diff_threshold = (opt::load_ratio_threshold +
  76                            opt::avg_load_ratio * total_load_average) / 100.0;
  77
  78     ctrl_close_pending = data_close_pending = neigh.size();
  79     close_received = false;
  80     finalizing = false;
  81
  82     all_comp_iter = comp_iter = lb_iter = 0;
  83
  84     lb_thread = new_msg_thread("loba",
  85                                std::bind(&process::load_balance_loop, this));
  86
  87     e_xbt_log_priority_t logp = xbt_log_priority_verbose;
  88     if (!LOG_ISENABLED(logp))
  89         return;
  90     std::ostringstream oss;
  91     oss << neigh.size() << " neighbor";
  92     if (!neigh.empty()) {
  93         oss << ESSE(neigh.size()) << ": ";
  94         std::transform(neigh.begin(), neigh.end() - 1,
  95                        std::ostream_iterator<const char*>(oss, ", "),
  96                        std::mem_fn(&neighbor::get_name));
  97         oss << neigh.back().get_name();
  98     }
  99     XBT_LOG(logp, "Got %s.", oss.str().c_str());
 100     print_loads(false, logp);
 101 }
 102
 103 process::~process()
 104 {
 105     delete lb_thread;
 106     total_load_exit += real_load;
 107     xbt_assert(received_load == 0.0,
 108                "received_load is %g, but should be 0.0 !", received_load);
 109     if (opt::log_rate < 0)
 110         return;
 111     XBT_INFO("Final load after %d:%d:%d iterations: %g",
 112              lb_iter, comp_iter, all_comp_iter, real_load);
 113     if (convergence >= 0.0)
 114         XBT_INFO("Convergence within %g%% was achieved at time %g",
 115                  opt::avg_load_ratio, convergence);
 116     else
 117         XBT_INFO("Convergence within %g%% was not achieved",
 118                  opt::avg_load_ratio);
 119     XBT_VERB("Expected load was: %g", expected_load);
 120     XBT_VERB("Total computation for this process: %g", get_comp_amount());
 121     print_loads(true, xbt_log_priority_debug);
 122 }
 123
 124 int process::run()
 125 {
 126     if (opt::log_rate >= 0) {
 127         XBT_INFO("Initial load: %g", real_load);
 128         XBT_VERB("Initial expected load: %g", expected_load);
 129     }
 130     XBT_VERB("Starting...");
 131     mutex.acquire();
 132     lb_thread->start();
 133     while (lb_iter <= opt::comp_iter_delay)
 134         cond.wait(mutex);
 135     mutex.release();
 136     double sleep_duration = opt::comp_time_delay - MSG_get_clock();
 137     if (sleep_duration > 0.0)
 138         MSG_process_sleep(sleep_duration);
 139     compute_loop();
 140     lb_thread->wait();
 141     XBT_VERB("Done.");
 142     return 0;
 143 }
 144
 145 void process::load_balance_loop()
 146 {
 147     using std::placeholders::_1;
 148
 149     double next_iter_after_date = MSG_get_clock() + opt::min_lb_iter_duration;
 150     while (still_running()) {
 151         if (lb_iter == opt::comp_iter_delay) {
 152             mutex.acquire();
 153             ++lb_iter;
 154             cond.signal();
 155             mutex.release();
 156         } else {
 157             ++lb_iter;
 158         }
 159
 160         ctrl_receive(0.0);
 161
 162         mutex.acquire();
 163         if (!opt::bookkeeping)
 164             expected_load = real_load - get_sum_of_to_send();
 165         // nothing to do with opt::bookkeeping
 166
 167         if (opt::log_rate && lb_iter % opt::log_rate == 0) {
 168             XBT_INFO("(%u:%u:%u) current load: %g",
 169                      lb_iter, comp_iter, all_comp_iter, real_load);
 170             XBT_VERB("... expected load: %g", expected_load);
 171         }
 172
 173         if (expected_load > 0.0)
 174             load_balance();
 175
 176         print_loads(true, xbt_log_priority_debug);
 177
 178         // send
 179         comm.ctrl_flush(false);
 180         std::for_each(neigh.begin(), neigh.end(),
 181                       std::bind(&process::ctrl_send, this, _1));
 182         prev_load_broadcast = expected_load;
 183         mutex.release();
 184
 185         sleep_until_date(next_iter_after_date, opt::min_lb_iter_duration);
 186     }
 187
 188     XBT_VERB("Going to finalize for %s...", __func__);
 189     XBT_DEBUG("send CTRL_CLOSE to %zu neighbor%s",
 190               neigh.size(), ESSE(neigh.size()));
 191     std::for_each(neigh.begin(), neigh.end(),
 192                   std::bind(&process::ctrl_close, this, _1));
 193     while (ctrl_close_pending) {
 194         comm.ctrl_flush(false);
 195         XBT_DEBUG("waiting for %d CTRL_CLOSE", ctrl_close_pending);
 196         ctrl_receive(-1.0);
 197     }
 198     comm.ctrl_flush(true);
 199 }
 200
 201 void process::compute_loop()
 202 {
 203     using std::placeholders::_1;
 204
 205     double next_iter_after_date = MSG_get_clock() + opt::min_comp_iter_duration;
 206     double idle_since_date = 0.0;
 207     while (still_running()) {
 208
 209         do {
 210             // receive
 211             // if there is something to compute, do not block
 212             // else, block the duration of an *lb* iteration
 213             data_receive(real_load > 0.0 ? 0.0 : opt::min_lb_iter_duration);
 214
 215             // send
 216             comm.data_flush(false);
 217             mutex.acquire();
 218             real_load += received_load;
 219             received_load = 0.0;
 220             std::for_each(neigh.begin(), neigh.end(),
 221                           std::bind(&process::data_send, this, _1));
 222             mutex.release();
 223
 224             ++all_comp_iter;
 225
 226         } while (real_load == 0.0);
 227
 228         convergence_check();
 229
 230         // compute
 231         idle_duration += MSG_get_clock() - idle_since_date;
 232         ++comp_iter;
 233         double flops = opt::comp_cost(real_load);
 234         m_task_t task = MSG_task_create("computation", flops, 0.0, NULL);
 235         TRACE_msg_set_task_category(task, TRACE_CAT_COMP);
 236         XBT_DEBUG("compute %g flop%s", flops, ESSE(flops));
 237         MSG_task_execute(task);
 238         add_comp_amount(flops);
 239         MSG_task_destroy(task);
 240
 241         idle_since_date = MSG_get_clock();
 242
 243         sleep_until_date(next_iter_after_date, opt::min_comp_iter_duration);
 244     }
 245
 246     XBT_VERB("Going to finalize for %s...", __func__);
 247     finalizing = true;
 248     XBT_DEBUG("send DATA_CLOSE to %zu neighbor%s",
 249               neigh.size(), ESSE(neigh.size()));
 250     std::for_each(neigh.begin(), neigh.end(),
 251                   std::bind(&process::data_close, this, _1));
 252     while (data_close_pending) {
 253         comm.data_flush(false);
 254         XBT_DEBUG("waiting for %d DATA_CLOSE", data_close_pending);
 255         data_receive(-1.0);
 256     }
 257     real_load += received_load;
 258     received_load = 0.0;
 259     total_load_running -= real_load;
 260     convergence_check();
 261     comm.data_flush(true);
 262 }
 263
 264 void process::convergence_check()
 265 {
 266     double load_diff = std::fabs(real_load - total_load_average);
 267     bool converged = load_diff <= load_diff_threshold;
 268
 269     if (convergence >= 0.0) {
 270         if (!converged) {
 271             XBT_VERB("current load has diverged: %g (%.4g%%)",
 272                      real_load, 100.0 * load_diff / total_load_average);
 273             convergence = -1.0;
 274         }
 275     } else {
 276         if (converged) {
 277             XBT_VERB("current load has converged: %g (%.4g%%)",
 278                      real_load,  100.0 * load_diff / total_load_average);
 279             convergence = MSG_get_clock();
 280         }
 281     }
 282 }
 283
 284 bool process::still_running()
 285 {
 286     static bool last_status = true;
 287
 288     if (!last_status) {
 289         /* nop */
 290
 291     } else if (opt::exit_request) {
 292         XBT_VERB("Global exit requested");
 293         last_status = false;
 294
 295     } else if (opt::time_limit && MSG_get_clock() >= opt::time_limit) {
 296         XBT_VERB("Reached time limit: %g/%g", MSG_get_clock(), opt::time_limit);
 297         last_status = false;
 298
 299     } else if (opt::lb_maxiter && lb_iter >= opt::lb_maxiter) {
 300         XBT_VERB("Reached lb_maxiter: %d/%d", lb_iter, opt::lb_maxiter);
 301         last_status = false;
 302
 303     } else if (opt::comp_maxiter && comp_iter >= opt::comp_maxiter) {
 304         XBT_VERB("Reached comp_maxiter: %d/%d", comp_iter, opt::comp_maxiter);
 305         last_status = false;
 306
 307     } else if (opt::exit_on_close && close_received) {
 308         XBT_VERB("Close received");
 309         last_status = false;
 310
 311     } else if (real_load == 0.0 && !data_close_pending) {
 312         XBT_VERB("I'm a poor lonesome process, and I have no load...");
 313         last_status = false;
 314
 315     } else if (100.0 * total_load_running / total_load_init <=
 316                opt::load_ratio_threshold) {
 317         // fixme: this check should be implemented with a distributed
 318         // algorithm, and not a shared global variable!
 319         XBT_VERB("No more load to balance in system.");
 320         last_status = false;
 321     }
 322
 323     return last_status;
 324 }
 325
 326 double process::get_sum_of_to_send() const
 327 {
 328     using std::placeholders::_1;
 329     using std::placeholders::_2;
 330
 331     return std::accumulate(neigh.begin(), neigh.end(), 0.0,
 332                            std::bind(std::plus<double>(), _1,
 333                                      std::bind(&neighbor::get_to_send, _2)));
 334 }
 335
 336 void process::load_balance()
 337 {
 338     if (lb_iter == 1)           // warn only once
 339         XBT_WARN("process::load_balance() is a no-op!");
 340 }
 341
 342 void process::send(neighbor& nb, double amount)
 343 {
 344     expected_load -= amount;
 345     nb.set_to_send(nb.get_to_send() + amount);
 346     nb.set_load(nb.get_load() + amount);
 347 }
 348
 349 void process::ctrl_send(neighbor& nb)
 350 {
 351     double info_to_send = expected_load;
 352     double debt_to_send;
 353     if (opt::bookkeeping) {     // bookkeeping
 354         debt_to_send = nb.get_to_send();
 355         if (debt_to_send > 0.0) {
 356             nb.set_to_send(0.0);
 357             nb.set_debt(nb.get_debt() + debt_to_send);
 358         }
 359     } else {                    // !bookkeeping
 360         debt_to_send = 0.0;
 361     }
 362     if (info_to_send != prev_load_broadcast || debt_to_send > 0.0) {
 363         message* msg = new message(message::CTRL, info_to_send, debt_to_send);
 364         add_ctrl_send_mesg(msg->get_size());
 365         comm.ctrl_send(nb.get_ctrl_mbox(), msg);
 366     }
 367 }
 368
 369 double process::compute_load_to_send(double desired)
 370 {
 371     if (opt::integer_transfer)
 372         desired = std::floor(desired);
 373     return desired >= opt::min_transfer_amount ? desired : 0.0;
 374 }
 375
 376 void process::data_send(neighbor& nb)
 377 {
 378     double load_to_send;
 379     if (opt::bookkeeping) {     // bookkeeping
 380         double excess_load;     // load amount we are able to send
 381         if (opt::egocentric)
 382             excess_load = std::max(0.0, real_load - expected_load);
 383         else
 384             excess_load = real_load;
 385
 386         double balance = nb.get_debt() - nb.get_credit();
 387         load_to_send = std::min(excess_load,
 388                                 std::max(0.0, balance));
 389
 390         // adjust load to send (rounding, truncation, etc.)
 391         load_to_send = compute_load_to_send(load_to_send);
 392         if (load_to_send > 0.0)
 393             nb.set_debt(nb.get_debt() - load_to_send);
 394     } else {                    // !bookkeeping
 395         load_to_send = compute_load_to_send(nb.get_to_send());
 396         if (load_to_send > 0.0)
 397             nb.set_to_send(nb.get_to_send() - load_to_send);
 398     }
 399     real_load -= load_to_send;
 400     while (load_to_send > 0.0) {
 401         double amount;
 402         if (opt::max_transfer_amount)
 403             amount = std::min(load_to_send, opt::max_transfer_amount);
 404         else
 405             amount = load_to_send;
 406         message* msg = new message(message::DATA, amount);
 407         add_data_send_mesg(msg->get_size());
 408         comm.data_send(nb.get_data_mbox(), msg);
 409         load_to_send -= amount;
 410     }
 411 }
 412
 413 void process::ctrl_close(neighbor& nb)
 414 {
 415     comm.ctrl_send(nb.get_ctrl_mbox(), new message(message::CTRL_CLOSE, 0.0));
 416 }
 417
 418 void process::data_close(neighbor& nb)
 419 {
 420     comm.data_send(nb.get_data_mbox(), new message(message::DATA_CLOSE, 0.0));
 421 }
 422
 423 void process::ctrl_receive(double timeout)
 424 {
 425     message* msg;
 426     m_host_t from;
 427
 428     XBT_DEBUG("%sblocking receive on ctrl (%g)", "\0non-" + !timeout, timeout);
 429     while (ctrl_close_pending && comm.ctrl_recv(msg, from, timeout)) {
 430         if (msg->get_type() != message::CTRL_CLOSE)
 431             add_ctrl_recv_mesg(msg->get_size());
 432         handle_message(msg, from);
 433         timeout = 0.0;
 434     }
 435 }
 436
 437 void process::data_receive(double timeout)
 438 {
 439     message* msg;
 440     m_host_t from;
 441
 442     XBT_DEBUG("%sblocking receive on data (%g)", "\0non-" + !timeout, timeout);
 443     while (data_close_pending && comm.data_recv(msg, from, timeout)) {
 444         if (msg->get_type() != message::DATA_CLOSE)
 445             add_data_recv_mesg(msg->get_size());
 446         handle_message(msg, from);
 447         timeout = 0.0;
 448     }
 449 }
 450
 451 void process::handle_message(message* msg, m_host_t from)
 452 {
 453     switch (msg->get_type()) {
 454     case message::CTRL: {
 455         neighbor* n = rev_neigh[from];
 456         n->set_load(msg->get_amount() + n->get_to_send());
 457         if (opt::bookkeeping) {
 458             double credit = msg->get_credit();
 459             expected_load += credit;
 460             n->set_credit(n->get_credit() + credit);
 461         }
 462         break;
 463     }
 464     case message::DATA: {
 465         neighbor* n = rev_neigh[from];
 466         double ld = msg->get_amount();
 467         received_load += ld;
 468         n->set_credit(n->get_credit() - ld);
 469         break;
 470     }
 471     case message::CTRL_CLOSE:
 472         ctrl_close_pending--;
 473         close_received = true;
 474         break;
 475     case message::DATA_CLOSE:
 476         data_close_pending--;
 477         close_received = true;
 478         break;
 479     }
 480     delete msg;
 481 }
 482
 483 #define print_loads_generic(vec, verbose, logp, cat)                    \
 484     if (_XBT_LOG_ISENABLEDV((*cat), logp)) {                            \
 485         using std::placeholders::_1;                                    \
 486         XBT_XCLOG(cat, logp, "My load: %g (real); %g (expected).  "     \
 487                   "Neighbor loads:", real_load, expected_load);         \
 488         std::for_each(vec.begin(), vec.end(),                           \
 489                       std::bind(&neighbor::print, _1, verbose, logp, cat)); \
 490     } else ((void)0)
 491
 492 void process::print_loads(bool verbose,
 493                           e_xbt_log_priority_t logp,
 494                           xbt_log_category_t cat) const
 495 {
 496     print_loads_generic(neigh, verbose, logp, cat);
 497 }
 498
 499 void process::print_loads_p(bool verbose,
 500                             e_xbt_log_priority_t logp,
 501                             xbt_log_category_t cat) const
 502 {
 503     print_loads_generic(pneigh, verbose, logp, cat);
 504 }
 505
 506 #undef print_loads_generic
 507
 508 // Local variables:
 509 // mode: c++
 510 // End: