src/simix/smx_context_sysv.c

   1 /* context_sysv - context switching with ucontexts from System V           */
   2
   3 /* Copyright (c) 2009-2014. The SimGrid Team.
   4  * All rights reserved.                                                     */
   5
   6 /* This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the license (GNU LGPL) which comes with this package. */
   8
   9 #include <stdarg.h>
  10
  11 #include "xbt/parmap.h"
  12 #include "smx_private.h"
  13 #include "internal_config.h"
  14 #include "context_sysv_config.h"        /* loads context system definitions */
  15 #include "mc/mc.h"
  16
  17 #ifdef _XBT_WIN32
  18 #  include <win32_ucontext.h>     /* context relative declarations */
  19 #else
  20 #  include <ucontext.h>           /* context relative declarations */
  21 #endif
  22
  23 #ifdef HAVE_VALGRIND_VALGRIND_H
  24 #  include <valgrind/valgrind.h>
  25 #endif                          /* HAVE_VALGRIND_VALGRIND_H */
  26
  27 XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(simix_context);
  28
  29 typedef struct s_smx_ctx_sysv {
  30   s_smx_ctx_base_t super;       /* Fields of super implementation */
  31   ucontext_t uc;                /* the ucontext that executes the code */
  32 #ifdef HAVE_VALGRIND_VALGRIND_H
  33   unsigned int valgrind_stack_id;       /* the valgrind stack id */
  34 #endif
  35   char stack[0];                /* the thread stack (must remain the last element of the structure) */
  36 } s_smx_ctx_sysv_t, *smx_ctx_sysv_t;
  37
  38 #ifdef CONTEXT_THREADS
  39 static xbt_parmap_t sysv_parmap;
  40 static smx_ctx_sysv_t* sysv_workers_context;   /* space to save the worker's context in each thread */
  41 static unsigned long sysv_threads_working;     /* number of threads that have started their work */
  42 static xbt_os_thread_key_t sysv_worker_id_key; /* thread-specific storage for the thread id */
  43 #endif
  44 static unsigned long sysv_process_index = 0;   /* index of the next process to run in the
  45                                                 * list of runnable processes */
  46 static smx_ctx_sysv_t sysv_maestro_context;
  47
  48 static int smx_ctx_sysv_factory_finalize(smx_context_factory_t *factory);
  49 static smx_context_t
  50 smx_ctx_sysv_create_context_sized(size_t structure_size,
  51                                   xbt_main_func_t code, int argc,
  52                                   char **argv,
  53                                   void_pfn_smxprocess_t cleanup_func,
  54                                   smx_process_t process);
  55 static void smx_ctx_sysv_free(smx_context_t context);
  56 static smx_context_t
  57 smx_ctx_sysv_create_context(xbt_main_func_t code, int argc, char **argv,
  58     void_pfn_smxprocess_t cleanup_func, smx_process_t process);
  59
  60 static void smx_ctx_sysv_wrapper(int count, ...);
  61
  62 static void smx_ctx_sysv_stop_serial(smx_context_t context);
  63 static void smx_ctx_sysv_suspend_serial(smx_context_t context);
  64 static void smx_ctx_sysv_resume_serial(smx_process_t first_process);
  65 static void smx_ctx_sysv_runall_serial(void);
  66
  67 static void smx_ctx_sysv_stop_parallel(smx_context_t context);
  68 static void smx_ctx_sysv_suspend_parallel(smx_context_t context);
  69 static void smx_ctx_sysv_resume_parallel(smx_process_t first_process);
  70 static void smx_ctx_sysv_runall_parallel(void);
  71
  72 /* This is a bit paranoid about sizeof(smx_ctx_sysv_t) not being a multiple of
  73  * sizeof(int), but it doesn't harm. */
  74 #define CTX_ADDR_LEN                            \
  75   (sizeof(smx_ctx_sysv_t) / sizeof(int) +       \
  76    !!(sizeof(smx_ctx_sysv_t) % sizeof(int)))
  77
  78 void SIMIX_ctx_sysv_factory_init(smx_context_factory_t *factory)
  79 {
  80   smx_ctx_base_factory_init(factory);
  81   XBT_VERB("Activating SYSV context factory");
  82
  83   (*factory)->finalize = smx_ctx_sysv_factory_finalize;
  84   (*factory)->create_context = smx_ctx_sysv_create_context;
  85   /* Do not overload that method (*factory)->finalize */
  86   (*factory)->free = smx_ctx_sysv_free;
  87   (*factory)->name = "smx_sysv_context_factory";
  88
  89   if (SIMIX_context_is_parallel()) {
  90 #ifdef CONTEXT_THREADS  /* To use parallel ucontexts a thread pool is needed */
  91     int nthreads = SIMIX_context_get_nthreads();
  92     sysv_parmap = xbt_parmap_new(nthreads, SIMIX_context_get_parallel_mode());
  93     sysv_workers_context = xbt_new(smx_ctx_sysv_t, nthreads);
  94     sysv_maestro_context = NULL;
  95     xbt_os_thread_key_create(&sysv_worker_id_key);
  96     (*factory)->stop = smx_ctx_sysv_stop_parallel;
  97     (*factory)->suspend = smx_ctx_sysv_suspend_parallel;
  98     (*factory)->runall = smx_ctx_sysv_runall_parallel;
  99 #else
 100     THROWF(arg_error, 0, "No thread support for parallel context execution");
 101 #endif
 102   } else {
 103     (*factory)->stop = smx_ctx_sysv_stop_serial;
 104     (*factory)->suspend = smx_ctx_sysv_suspend_serial;
 105     (*factory)->runall = smx_ctx_sysv_runall_serial;
 106   }
 107 }
 108
 109 static int smx_ctx_sysv_factory_finalize(smx_context_factory_t *factory)
 110 {
 111 #ifdef CONTEXT_THREADS
 112   if (sysv_parmap)
 113     xbt_parmap_destroy(sysv_parmap);
 114   xbt_free(sysv_workers_context);
 115 #endif
 116   return smx_ctx_base_factory_finalize(factory);
 117 }
 118
 119 static smx_context_t
 120 smx_ctx_sysv_create_context_sized(size_t size, xbt_main_func_t code,
 121                                   int argc, char **argv,
 122                                   void_pfn_smxprocess_t cleanup_func,
 123                                   smx_process_t process)
 124 {
 125   int ctx_addr[CTX_ADDR_LEN];
 126   smx_ctx_sysv_t context =
 127       (smx_ctx_sysv_t) smx_ctx_base_factory_create_context_sized(size,
 128                                                                  code,
 129                                                                  argc,
 130                                                                  argv,
 131                                                                  cleanup_func,
 132                                                                  process);
 133
 134   /* if the user provided a function for the process then use it,
 135      otherwise it is the context for maestro */
 136   if (code) {
 137
 138     getcontext(&(context->uc));
 139
 140     context->uc.uc_link = NULL;
 141
 142     context->uc.uc_stack.ss_sp =
 143         pth_skaddr_makecontext(context->stack, smx_context_stack_size);
 144
 145     context->uc.uc_stack.ss_size =
 146         pth_sksize_makecontext(context->stack, smx_context_stack_size);
 147
 148 #ifdef HAVE_VALGRIND_VALGRIND_H
 149     context->valgrind_stack_id =
 150         VALGRIND_STACK_REGISTER(context->uc.uc_stack.ss_sp,
 151                                 ((char *) context->uc.uc_stack.ss_sp) +
 152                                 context->uc.uc_stack.ss_size);
 153 #endif                          /* HAVE_VALGRIND_VALGRIND_H */
 154     memcpy(ctx_addr, &context, sizeof(smx_ctx_sysv_t));
 155     switch (CTX_ADDR_LEN) {
 156     case 1:
 157       makecontext(&context->uc, (void (*)())smx_ctx_sysv_wrapper,
 158                   1, ctx_addr[0]);
 159       break;
 160     case 2:
 161       makecontext(&context->uc, (void (*)())smx_ctx_sysv_wrapper,
 162                   2, ctx_addr[0], ctx_addr[1]);
 163       break;
 164     default:
 165       xbt_die("Ucontexts are not supported on this arch yet (addr len = %zu/%zu = %zu)",
 166               sizeof(smx_ctx_sysv_t), sizeof(int), CTX_ADDR_LEN);
 167     }
 168   } else {
 169     if (process != NULL && sysv_maestro_context == NULL)
 170       sysv_maestro_context = context;
 171   }
 172
 173   if(MC_is_active() && code)
 174     MC_new_stack_area(context, ((smx_context_t)context)->process->name,
 175                       &(context->uc), size);
 176
 177   return (smx_context_t) context;
 178 }
 179
 180 static smx_context_t
 181 smx_ctx_sysv_create_context(xbt_main_func_t code, int argc, char **argv,
 182                             void_pfn_smxprocess_t cleanup_func,
 183                             smx_process_t process)
 184 {
 185
 186   return smx_ctx_sysv_create_context_sized(sizeof(s_smx_ctx_sysv_t) +
 187                                            smx_context_stack_size,
 188                                            code, argc, argv, cleanup_func,
 189                                            process);
 190
 191 }
 192
 193 static void smx_ctx_sysv_free(smx_context_t context)
 194 {
 195
 196   if (context) {
 197
 198 #ifdef HAVE_VALGRIND_VALGRIND_H
 199     VALGRIND_STACK_DEREGISTER(((smx_ctx_sysv_t)
 200                                context)->valgrind_stack_id);
 201 #endif                          /* HAVE_VALGRIND_VALGRIND_H */
 202
 203   }
 204   smx_ctx_base_free(context);
 205 }
 206
 207 static void smx_ctx_sysv_wrapper(int first, ...)
 208 {
 209   int ctx_addr[CTX_ADDR_LEN];
 210   smx_ctx_sysv_t context;
 211
 212   ctx_addr[0] = first;
 213   if (CTX_ADDR_LEN > 1) {
 214     va_list ap;
 215     int i;
 216     va_start(ap, first);
 217     for (i = 1; i < CTX_ADDR_LEN; i++)
 218       ctx_addr[i] = va_arg(ap, int);
 219     va_end(ap);
 220   }
 221   memcpy(&context, ctx_addr, sizeof(smx_ctx_sysv_t));
 222   (context->super.code) (context->super.argc, context->super.argv);
 223
 224   simix_global->context_factory->stop((smx_context_t) context);
 225 }
 226
 227 static void smx_ctx_sysv_stop_serial(smx_context_t context)
 228 {
 229   smx_ctx_base_stop(context);
 230   smx_ctx_sysv_suspend_serial(context);
 231 }
 232
 233 static void smx_ctx_sysv_suspend_serial(smx_context_t context)
 234 {
 235   /* determine the next context */
 236   smx_context_t next_context;
 237   unsigned long int i = sysv_process_index++;
 238
 239   if (i < xbt_dynar_length(simix_global->process_to_run)) {
 240     /* execute the next process */
 241     XBT_DEBUG("Run next process");
 242     next_context = xbt_dynar_get_as(
 243         simix_global->process_to_run,i, smx_process_t)->context;
 244   }
 245   else {
 246     /* all processes were run, return to maestro */
 247     XBT_DEBUG("No more process to run");
 248     next_context = (smx_context_t) sysv_maestro_context;
 249   }
 250   SIMIX_context_set_current(next_context);
 251   swapcontext(&((smx_ctx_sysv_t) context)->uc,
 252       &((smx_ctx_sysv_t) next_context)->uc);
 253 }
 254
 255 static void smx_ctx_sysv_resume_serial(smx_process_t first_process)
 256 {
 257   smx_context_t context = first_process->context;
 258   SIMIX_context_set_current(context);
 259   swapcontext(&sysv_maestro_context->uc,
 260       &((smx_ctx_sysv_t) context)->uc);
 261 }
 262
 263 static void smx_ctx_sysv_runall_serial(void)
 264 {
 265   smx_process_t first_process =
 266       xbt_dynar_get_as(simix_global->process_to_run, 0, smx_process_t);
 267   sysv_process_index = 1;
 268
 269   /* execute the first process */
 270   smx_ctx_sysv_resume_serial(first_process);
 271 }
 272
 273 static void smx_ctx_sysv_stop_parallel(smx_context_t context)
 274 {
 275   smx_ctx_base_stop(context);
 276   smx_ctx_sysv_suspend_parallel(context);
 277 }
 278
 279 static void smx_ctx_sysv_suspend_parallel(smx_context_t context)
 280 {
 281 #ifdef CONTEXT_THREADS
 282   /* determine the next context */
 283   smx_process_t next_work = xbt_parmap_next(sysv_parmap);
 284   smx_context_t next_context;
 285   ucontext_t* next_stack;
 286
 287   if (next_work != NULL) {
 288     /* there is a next process to resume */
 289     XBT_DEBUG("Run next process");
 290     next_context = next_work->context;
 291     next_stack = &((smx_ctx_sysv_t) next_context)->uc;
 292   }
 293   else {
 294     /* all processes were run, go to the barrier */
 295     XBT_DEBUG("No more processes to run");
 296     unsigned long worker_id =
 297         (unsigned long) xbt_os_thread_get_specific(sysv_worker_id_key);
 298     next_context = (smx_context_t)sysv_workers_context[worker_id];
 299     next_stack = &((smx_ctx_sysv_t)next_context)->uc;
 300   }
 301
 302   SIMIX_context_set_current(next_context);
 303   swapcontext(&((smx_ctx_sysv_t) context)->uc, next_stack);
 304 #endif
 305 }
 306
 307 static void smx_ctx_sysv_resume_parallel(smx_process_t first_process)
 308 {
 309 #ifdef CONTEXT_THREADS
 310   unsigned long worker_id = __sync_fetch_and_add(&sysv_threads_working, 1);
 311   xbt_os_thread_set_specific(sysv_worker_id_key, (void*) worker_id);
 312   smx_ctx_sysv_t worker_context = (smx_ctx_sysv_t)SIMIX_context_self();
 313   sysv_workers_context[worker_id] = worker_context;
 314   ucontext_t* worker_stack = &worker_context->uc;
 315
 316   smx_context_t context = first_process->context;
 317   SIMIX_context_set_current(context);
 318   swapcontext(worker_stack, &((smx_ctx_sysv_t) context)->uc);
 319 #endif
 320 }
 321
 322 static void smx_ctx_sysv_runall_parallel(void)
 323 {
 324 #ifdef CONTEXT_THREADS
 325   sysv_threads_working = 0;
 326   xbt_parmap_apply(sysv_parmap, (void_f_pvoid_t) smx_ctx_sysv_resume_parallel,
 327       simix_global->process_to_run);
 328 #endif
 329 }