src/simix/smx_context_sysv.c

   1 /* context_sysv - context switching with ucontextes from System V           */
   2
   3 /* Copyright (c) 2009, 2010. 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 "simix/private.h"
  13 #include "gras_config.h"
  14 #include "context_sysv_config.h"        /* loads context system definitions */
  15
  16 #ifdef _XBT_WIN32
  17 #  include <win32_ucontext.h>     /* context relative declarations */
  18 #else
  19 #  include <ucontext.h>           /* context relative declarations */
  20 #endif
  21
  22 #ifdef HAVE_VALGRIND_VALGRIND_H
  23 #  include <valgrind/valgrind.h>
  24 #endif                          /* HAVE_VALGRIND_VALGRIND_H */
  25
  26 XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(simix_context);
  27
  28 typedef struct s_smx_ctx_sysv {
  29   s_smx_ctx_base_t super;       /* Fields of super implementation */
  30   ucontext_t uc;                /* the ucontext that executes the code */
  31 #ifdef HAVE_VALGRIND_VALGRIND_H
  32   unsigned int valgrind_stack_id;       /* the valgrind stack id */
  33 #endif
  34   char stack[0];                /* the thread stack (must remain the last element of the structure) */
  35 } s_smx_ctx_sysv_t, *smx_ctx_sysv_t;
  36
  37 #ifdef CONTEXT_THREADS
  38 static xbt_parmap_t sysv_parmap;
  39 static ucontext_t* sysv_workers_stacks;        /* space to save the worker's stack in each thread */
  40 static unsigned long sysv_threads_working;     /* number of threads that have started their work */
  41 static xbt_os_thread_key_t sysv_worker_id_key; /* thread-specific storage for the thread id */
  42 #endif
  43 static unsigned long sysv_process_index = 0;   /* index of the next process to run in the
  44                                                 * list of runnable processes */
  45 static smx_ctx_sysv_t sysv_maestro_context;
  46
  47 static int smx_ctx_sysv_factory_finalize(smx_context_factory_t *factory);
  48 static smx_context_t
  49 smx_ctx_sysv_create_context_sized(size_t structure_size,
  50                                   xbt_main_func_t code, int argc,
  51                                   char **argv,
  52                                   void_pfn_smxprocess_t cleanup_func,
  53                                   void *data);
  54 static void smx_ctx_sysv_free(smx_context_t context);
  55 static smx_context_t smx_ctx_sysv_self_parallel(void);
  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, void* data);
  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_VOIDP not being a multiple of SIZEOF_INT,
  73  * but it doesn't harm. */
  74 #define CTX_ADDR_LEN (SIZEOF_VOIDP / SIZEOF_INT + !!(SIZEOF_VOIDP % SIZEOF_INT))
  75 union u_ctx_addr {
  76   void *addr;
  77   int intv[CTX_ADDR_LEN];
  78 };
  79 #if (CTX_ADDR_LEN == 1)
  80 #  define CTX_ADDR_SPLIT(u) (u).intv[0]
  81 #elif (CTX_ADDR_LEN == 2)
  82 #  define CTX_ADDR_SPLIT(u) (u).intv[0], (u).intv[1]
  83 #else
  84 #  error Your architecture is not supported yet
  85 #endif
  86
  87 void SIMIX_ctx_sysv_factory_init(smx_context_factory_t *factory)
  88 {
  89   smx_ctx_base_factory_init(factory);
  90   XBT_VERB("Activating SYSV context factory");
  91
  92   (*factory)->finalize = smx_ctx_sysv_factory_finalize;
  93   (*factory)->create_context = smx_ctx_sysv_create_context;
  94   /* Do not overload that method (*factory)->finalize */
  95   (*factory)->free = smx_ctx_sysv_free;
  96   (*factory)->name = "smx_sysv_context_factory";
  97
  98   if (SIMIX_context_is_parallel()) {
  99 #ifdef CONTEXT_THREADS  /* To use parallel ucontexts a thread pool is needed */
 100     int nthreads = SIMIX_context_get_nthreads();
 101     sysv_parmap = xbt_parmap_new(nthreads, SIMIX_context_get_parallel_mode());
 102     sysv_workers_stacks = xbt_new(ucontext_t, nthreads);
 103     xbt_os_thread_key_create(&sysv_worker_id_key);
 104     (*factory)->stop = smx_ctx_sysv_stop_parallel;
 105     (*factory)->suspend = smx_ctx_sysv_suspend_parallel;
 106     (*factory)->runall = smx_ctx_sysv_runall_parallel;
 107 #else
 108     THROWF(arg_error, 0, "No thread support for parallel context execution");
 109 #endif
 110   } else {
 111     (*factory)->stop = smx_ctx_sysv_stop_serial;
 112     (*factory)->suspend = smx_ctx_sysv_suspend_serial;
 113     (*factory)->runall = smx_ctx_sysv_runall_serial;
 114   }
 115 }
 116
 117 static int smx_ctx_sysv_factory_finalize(smx_context_factory_t *factory)
 118 {
 119 #ifdef CONTEXT_THREADS
 120   if (sysv_parmap)
 121     xbt_parmap_destroy(sysv_parmap);
 122   xbt_free(sysv_workers_stacks);
 123 #endif
 124   return smx_ctx_base_factory_finalize(factory);
 125 }
 126
 127 static smx_context_t
 128 smx_ctx_sysv_create_context_sized(size_t size, xbt_main_func_t code,
 129                                   int argc, char **argv,
 130                                   void_pfn_smxprocess_t cleanup_func,
 131                                   void *data)
 132 {
 133   union u_ctx_addr ctx_addr;
 134   smx_ctx_sysv_t context =
 135       (smx_ctx_sysv_t) smx_ctx_base_factory_create_context_sized(size,
 136                                                                  code,
 137                                                                  argc,
 138                                                                  argv,
 139                                                                  cleanup_func,
 140                                                                  data);
 141
 142   /* if the user provided a function for the process then use it,
 143      otherwise it is the context for maestro */
 144   if (code) {
 145
 146     getcontext(&(context->uc));
 147
 148     context->uc.uc_link = NULL;
 149
 150     context->uc.uc_stack.ss_sp =
 151         pth_skaddr_makecontext(context->stack, smx_context_stack_size);
 152
 153     context->uc.uc_stack.ss_size =
 154         pth_sksize_makecontext(context->stack, smx_context_stack_size);
 155
 156 #ifdef HAVE_VALGRIND_VALGRIND_H
 157     context->valgrind_stack_id =
 158         VALGRIND_STACK_REGISTER(context->uc.uc_stack.ss_sp,
 159                                 ((char *) context->uc.uc_stack.ss_sp) +
 160                                 context->uc.uc_stack.ss_size);
 161 #endif                          /* HAVE_VALGRIND_VALGRIND_H */
 162     ctx_addr.addr = context;
 163     makecontext(&context->uc, (void (*)())smx_ctx_sysv_wrapper,
 164                 CTX_ADDR_LEN, CTX_ADDR_SPLIT(ctx_addr));
 165   } else {
 166     sysv_maestro_context = context;
 167   }
 168
 169   return (smx_context_t) context;
 170 }
 171
 172 static smx_context_t
 173 smx_ctx_sysv_create_context(xbt_main_func_t code, int argc, char **argv,
 174     void_pfn_smxprocess_t cleanup_func,
 175     void *data)
 176 {
 177
 178   return smx_ctx_sysv_create_context_sized(sizeof(s_smx_ctx_sysv_t) + smx_context_stack_size,
 179                                            code, argc, argv, cleanup_func,
 180                                            data);
 181
 182 }
 183
 184 static void smx_ctx_sysv_free(smx_context_t context)
 185 {
 186
 187   if (context) {
 188
 189 #ifdef HAVE_VALGRIND_VALGRIND_H
 190     VALGRIND_STACK_DEREGISTER(((smx_ctx_sysv_t)
 191                                context)->valgrind_stack_id);
 192 #endif                          /* HAVE_VALGRIND_VALGRIND_H */
 193
 194   }
 195   smx_ctx_base_free(context);
 196 }
 197
 198 static void smx_ctx_sysv_wrapper(int first, ...)
 199 {
 200   union u_ctx_addr ctx_addr;
 201   smx_ctx_sysv_t context;
 202
 203   ctx_addr.intv[0] = first;
 204   if (CTX_ADDR_LEN > 1) {
 205     va_list ap;
 206     int i;
 207     va_start(ap, first);
 208     for (i = 1; i < CTX_ADDR_LEN; i++)
 209       ctx_addr.intv[i] = va_arg(ap, int);
 210     va_end(ap);
 211   }
 212   context = ctx_addr.addr;
 213   (context->super.code) (context->super.argc, context->super.argv);
 214
 215   simix_global->context_factory->stop((smx_context_t) context);
 216 }
 217
 218 static void smx_ctx_sysv_stop_serial(smx_context_t context)
 219 {
 220   smx_ctx_base_stop(context);
 221   smx_ctx_sysv_suspend_serial(context);
 222 }
 223
 224 static void smx_ctx_sysv_suspend_serial(smx_context_t context)
 225 {
 226   /* determine the next context */
 227   smx_context_t next_context;
 228   unsigned long int i = sysv_process_index++;
 229
 230   if (i < xbt_dynar_length(simix_global->process_to_run)) {
 231     /* execute the next process */
 232     XBT_DEBUG("Run next process");
 233     next_context = xbt_dynar_get_as(
 234         simix_global->process_to_run,i, smx_process_t)->context;
 235   }
 236   else {
 237     /* all processes were run, return to maestro */
 238     XBT_DEBUG("No more process to run");
 239     next_context = (smx_context_t) sysv_maestro_context;
 240   }
 241   SIMIX_context_set_current(next_context);
 242   swapcontext(&((smx_ctx_sysv_t) context)->uc,
 243       &((smx_ctx_sysv_t) next_context)->uc);
 244 }
 245
 246 static void smx_ctx_sysv_resume_serial(smx_process_t first_process)
 247 {
 248   smx_context_t context = first_process->context;
 249   SIMIX_context_set_current(context);
 250   swapcontext(&sysv_maestro_context->uc,
 251       &((smx_ctx_sysv_t) context)->uc);
 252 }
 253
 254 static void smx_ctx_sysv_runall_serial(void)
 255 {
 256   if (!xbt_dynar_is_empty(simix_global->process_to_run)) {
 257     smx_process_t first_process =
 258         xbt_dynar_get_as(simix_global->process_to_run, 0, smx_process_t);
 259     sysv_process_index = 1;
 260
 261     /* execute the first process */
 262     smx_ctx_sysv_resume_serial(first_process);
 263   }
 264 }
 265
 266 static void smx_ctx_sysv_stop_parallel(smx_context_t context)
 267 {
 268   smx_ctx_base_stop(context);
 269   smx_ctx_sysv_suspend_parallel(context);
 270 }
 271
 272 static void smx_ctx_sysv_suspend_parallel(smx_context_t context)
 273 {
 274 #ifdef CONTEXT_THREADS
 275   /* determine the next context */
 276   smx_process_t next_work = xbt_parmap_next(sysv_parmap);
 277   smx_context_t next_context;
 278   ucontext_t* next_stack;
 279
 280   if (next_work != NULL) {
 281     /* there is a next process to resume */
 282     XBT_DEBUG("Run next process");
 283     next_context = next_work->context;
 284     next_stack = &((smx_ctx_sysv_t) next_context)->uc;
 285   }
 286   else {
 287     /* all processes were run, go to the barrier */
 288     XBT_DEBUG("No more processes to run");
 289     next_context = (smx_context_t) sysv_maestro_context;
 290     unsigned long worker_id =
 291         (unsigned long) xbt_os_thread_get_specific(sysv_worker_id_key);
 292     next_stack = &sysv_workers_stacks[worker_id];
 293   }
 294
 295   SIMIX_context_set_current(next_context);
 296   swapcontext(&((smx_ctx_sysv_t) context)->uc, next_stack);
 297 #endif
 298 }
 299
 300 static void smx_ctx_sysv_resume_parallel(smx_process_t first_process)
 301 {
 302 #ifdef CONTEXT_THREADS
 303   unsigned long worker_id = __sync_fetch_and_add(&sysv_threads_working, 1);
 304   xbt_os_thread_set_specific(sysv_worker_id_key, (void*) worker_id);
 305   ucontext_t* worker_stack = &sysv_workers_stacks[worker_id];
 306
 307   smx_context_t context = first_process->context;
 308   SIMIX_context_set_current(context);
 309   swapcontext(worker_stack, &((smx_ctx_sysv_t) context)->uc);
 310 #endif
 311 }
 312
 313 static void smx_ctx_sysv_runall_parallel(void)
 314 {
 315 #ifdef CONTEXT_THREADS
 316   sysv_threads_working = 0;
 317   xbt_parmap_apply(sysv_parmap, (void_f_pvoid_t) smx_ctx_sysv_resume_parallel,
 318       simix_global->process_to_run);
 319 #endif
 320 }