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 "smx_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
  56 smx_ctx_sysv_create_context(xbt_main_func_t code, int argc, char **argv,
  57     void_pfn_smxprocess_t cleanup_func, void* data);
  58
  59 static void smx_ctx_sysv_wrapper(int count, ...);
  60
  61 static void smx_ctx_sysv_stop_serial(smx_context_t context);
  62 static void smx_ctx_sysv_suspend_serial(smx_context_t context);
  63 static void smx_ctx_sysv_resume_serial(smx_process_t first_process);
  64 static void smx_ctx_sysv_runall_serial(void);
  65
  66 static void smx_ctx_sysv_stop_parallel(smx_context_t context);
  67 static void smx_ctx_sysv_suspend_parallel(smx_context_t context);
  68 static void smx_ctx_sysv_resume_parallel(smx_process_t first_process);
  69 static void smx_ctx_sysv_runall_parallel(void);
  70
  71 /* This is a bit paranoid about SIZEOF_VOIDP not being a multiple of SIZEOF_INT,
  72  * but it doesn't harm. */
  73 #define CTX_ADDR_LEN (SIZEOF_VOIDP / SIZEOF_INT + !!(SIZEOF_VOIDP % SIZEOF_INT))
  74 union u_ctx_addr {
  75   void *addr;
  76   int intv[CTX_ADDR_LEN];
  77 };
  78 #if (CTX_ADDR_LEN == 1)
  79 #  define CTX_ADDR_SPLIT(u) (u).intv[0]
  80 #elif (CTX_ADDR_LEN == 2)
  81 #  define CTX_ADDR_SPLIT(u) (u).intv[0], (u).intv[1]
  82 #else
  83 #  error Your architecture is not supported yet
  84 #endif
  85
  86 void SIMIX_ctx_sysv_factory_init(smx_context_factory_t *factory)
  87 {
  88   smx_ctx_base_factory_init(factory);
  89   XBT_VERB("Activating SYSV context factory");
  90
  91   (*factory)->finalize = smx_ctx_sysv_factory_finalize;
  92   (*factory)->create_context = smx_ctx_sysv_create_context;
  93   /* Do not overload that method (*factory)->finalize */
  94   (*factory)->free = smx_ctx_sysv_free;
  95   (*factory)->name = "smx_sysv_context_factory";
  96
  97   if (SIMIX_context_is_parallel()) {
  98 #ifdef CONTEXT_THREADS  /* To use parallel ucontexts a thread pool is needed */
  99     int nthreads = SIMIX_context_get_nthreads();
 100     sysv_parmap = xbt_parmap_new(nthreads, SIMIX_context_get_parallel_mode());
 101     sysv_workers_stacks = xbt_new(ucontext_t, nthreads);
 102     xbt_os_thread_key_create(&sysv_worker_id_key);
 103     (*factory)->stop = smx_ctx_sysv_stop_parallel;
 104     (*factory)->suspend = smx_ctx_sysv_suspend_parallel;
 105     (*factory)->runall = smx_ctx_sysv_runall_parallel;
 106 #else
 107     THROWF(arg_error, 0, "No thread support for parallel context execution");
 108 #endif
 109   } else {
 110     (*factory)->stop = smx_ctx_sysv_stop_serial;
 111     (*factory)->suspend = smx_ctx_sysv_suspend_serial;
 112     (*factory)->runall = smx_ctx_sysv_runall_serial;
 113   }
 114 }
 115
 116 static int smx_ctx_sysv_factory_finalize(smx_context_factory_t *factory)
 117 {
 118 #ifdef CONTEXT_THREADS
 119   if (sysv_parmap)
 120     xbt_parmap_destroy(sysv_parmap);
 121   xbt_free(sysv_workers_stacks);
 122 #endif
 123   return smx_ctx_base_factory_finalize(factory);
 124 }
 125
 126 static smx_context_t
 127 smx_ctx_sysv_create_context_sized(size_t size, xbt_main_func_t code,
 128                                   int argc, char **argv,
 129                                   void_pfn_smxprocess_t cleanup_func,
 130                                   void *data)
 131 {
 132   union u_ctx_addr ctx_addr;
 133   smx_ctx_sysv_t context =
 134       (smx_ctx_sysv_t) smx_ctx_base_factory_create_context_sized(size,
 135                                                                  code,
 136                                                                  argc,
 137                                                                  argv,
 138                                                                  cleanup_func,
 139                                                                  data);
 140
 141   /* if the user provided a function for the process then use it,
 142      otherwise it is the context for maestro */
 143   if (code) {
 144
 145     getcontext(&(context->uc));
 146
 147     context->uc.uc_link = NULL;
 148
 149     context->uc.uc_stack.ss_sp =
 150         pth_skaddr_makecontext(context->stack, smx_context_stack_size);
 151
 152     context->uc.uc_stack.ss_size =
 153         pth_sksize_makecontext(context->stack, smx_context_stack_size);
 154
 155 #ifdef HAVE_VALGRIND_VALGRIND_H
 156     context->valgrind_stack_id =
 157         VALGRIND_STACK_REGISTER(context->uc.uc_stack.ss_sp,
 158                                 ((char *) context->uc.uc_stack.ss_sp) +
 159                                 context->uc.uc_stack.ss_size);
 160 #endif                          /* HAVE_VALGRIND_VALGRIND_H */
 161     ctx_addr.addr = context;
 162     makecontext(&context->uc, (void (*)())smx_ctx_sysv_wrapper,
 163                 CTX_ADDR_LEN, CTX_ADDR_SPLIT(ctx_addr));
 164   } else {
 165     sysv_maestro_context = context;
 166   }
 167
 168   return (smx_context_t) context;
 169 }
 170
 171 static smx_context_t
 172 smx_ctx_sysv_create_context(xbt_main_func_t code, int argc, char **argv,
 173     void_pfn_smxprocess_t cleanup_func,
 174     void *data)
 175 {
 176
 177   return smx_ctx_sysv_create_context_sized(sizeof(s_smx_ctx_sysv_t) + smx_context_stack_size,
 178                                            code, argc, argv, cleanup_func,
 179                                            data);
 180
 181 }
 182
 183 static void smx_ctx_sysv_free(smx_context_t context)
 184 {
 185
 186   if (context) {
 187
 188 #ifdef HAVE_VALGRIND_VALGRIND_H
 189     VALGRIND_STACK_DEREGISTER(((smx_ctx_sysv_t)
 190                                context)->valgrind_stack_id);
 191 #endif                          /* HAVE_VALGRIND_VALGRIND_H */
 192
 193   }
 194   smx_ctx_base_free(context);
 195 }
 196
 197 static void smx_ctx_sysv_wrapper(int first, ...)
 198 {
 199   union u_ctx_addr ctx_addr;
 200   smx_ctx_sysv_t context;
 201
 202   ctx_addr.intv[0] = first;
 203   if (CTX_ADDR_LEN > 1) {
 204     va_list ap;
 205     int i;
 206     va_start(ap, first);
 207     for (i = 1; i < CTX_ADDR_LEN; i++)
 208       ctx_addr.intv[i] = va_arg(ap, int);
 209     va_end(ap);
 210   }
 211   context = ctx_addr.addr;
 212   (context->super.code) (context->super.argc, context->super.argv);
 213
 214   simix_global->context_factory->stop((smx_context_t) context);
 215 }
 216
 217 static void smx_ctx_sysv_stop_serial(smx_context_t context)
 218 {
 219   smx_ctx_base_stop(context);
 220   smx_ctx_sysv_suspend_serial(context);
 221 }
 222
 223 static void smx_ctx_sysv_suspend_serial(smx_context_t context)
 224 {
 225   /* determine the next context */
 226   smx_context_t next_context;
 227   unsigned long int i = sysv_process_index++;
 228
 229   if (i < xbt_dynar_length(simix_global->process_to_run)) {
 230     /* execute the next process */
 231     XBT_DEBUG("Run next process");
 232     next_context = xbt_dynar_get_as(
 233         simix_global->process_to_run,i, smx_process_t)->context;
 234   }
 235   else {
 236     /* all processes were run, return to maestro */
 237     XBT_DEBUG("No more process to run");
 238     next_context = (smx_context_t) sysv_maestro_context;
 239   }
 240   SIMIX_context_set_current(next_context);
 241   swapcontext(&((smx_ctx_sysv_t) context)->uc,
 242       &((smx_ctx_sysv_t) next_context)->uc);
 243 }
 244
 245 static void smx_ctx_sysv_resume_serial(smx_process_t first_process)
 246 {
 247   smx_context_t context = first_process->context;
 248   SIMIX_context_set_current(context);
 249   swapcontext(&sysv_maestro_context->uc,
 250       &((smx_ctx_sysv_t) context)->uc);
 251 }
 252
 253 static void smx_ctx_sysv_runall_serial(void)
 254 {
 255   if (!xbt_dynar_is_empty(simix_global->process_to_run)) {
 256     smx_process_t first_process =
 257         xbt_dynar_get_as(simix_global->process_to_run, 0, smx_process_t);
 258     sysv_process_index = 1;
 259
 260     /* execute the first process */
 261     smx_ctx_sysv_resume_serial(first_process);
 262   }
 263 }
 264
 265 static void smx_ctx_sysv_stop_parallel(smx_context_t context)
 266 {
 267   smx_ctx_base_stop(context);
 268   smx_ctx_sysv_suspend_parallel(context);
 269 }
 270
 271 static void smx_ctx_sysv_suspend_parallel(smx_context_t context)
 272 {
 273 #ifdef CONTEXT_THREADS
 274   /* determine the next context */
 275   smx_process_t next_work = xbt_parmap_next(sysv_parmap);
 276   smx_context_t next_context;
 277   ucontext_t* next_stack;
 278
 279   if (next_work != NULL) {
 280     /* there is a next process to resume */
 281     XBT_DEBUG("Run next process");
 282     next_context = next_work->context;
 283     next_stack = &((smx_ctx_sysv_t) next_context)->uc;
 284   }
 285   else {
 286     /* all processes were run, go to the barrier */
 287     XBT_DEBUG("No more processes to run");
 288     next_context = (smx_context_t) sysv_maestro_context;
 289     unsigned long worker_id =
 290         (unsigned long) xbt_os_thread_get_specific(sysv_worker_id_key);
 291     next_stack = &sysv_workers_stacks[worker_id];
 292   }
 293
 294   SIMIX_context_set_current(next_context);
 295   swapcontext(&((smx_ctx_sysv_t) context)->uc, next_stack);
 296 #endif
 297 }
 298
 299 static void smx_ctx_sysv_resume_parallel(smx_process_t first_process)
 300 {
 301 #ifdef CONTEXT_THREADS
 302   unsigned long worker_id = __sync_fetch_and_add(&sysv_threads_working, 1);
 303   xbt_os_thread_set_specific(sysv_worker_id_key, (void*) worker_id);
 304   ucontext_t* worker_stack = &sysv_workers_stacks[worker_id];
 305
 306   smx_context_t context = first_process->context;
 307   SIMIX_context_set_current(context);
 308   swapcontext(worker_stack, &((smx_ctx_sysv_t) context)->uc);
 309 #endif
 310 }
 311
 312 static void smx_ctx_sysv_runall_parallel(void)
 313 {
 314 #ifdef CONTEXT_THREADS
 315   sysv_threads_working = 0;
 316   xbt_parmap_apply(sysv_parmap, (void_f_pvoid_t) smx_ctx_sysv_resume_parallel,
 317       simix_global->process_to_run);
 318 #endif
 319 }