X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/0b2b203572323552d916d5d2c60d100a27ca7f72..0386b99694ba4c3ab18048e7a57d46bc34201bfb:/src/simix/smx_context_sysv.c diff --git a/src/simix/smx_context_sysv.c b/src/simix/smx_context_sysv.c index d8f90fe37e..7fc7f6f13d 100644 --- a/src/simix/smx_context_sysv.c +++ b/src/simix/smx_context_sysv.c @@ -15,7 +15,7 @@ #include "mc/mc.h" #ifdef _XBT_WIN32 -# include /* context relative declarations */ +# include /* context relative declarations */ #else # include /* context relative declarations */ #endif @@ -240,54 +240,70 @@ static void smx_ctx_sysv_stop_parallel(smx_context_t context) smx_ctx_sysv_suspend_parallel(context); } -static void smx_ctx_sysv_suspend_parallel(smx_context_t context) -{ +/* This function is called by maestro at the beginning of a scheduling round to get all working threads executing some stuff + * It is much easier to understand what happens if you see the working threads as bodies that swap their soul for the + * ones of the simulated processes that must run. + */ +static void smx_ctx_sysv_runall_parallel(void) { +#ifdef CONTEXT_THREADS + sysv_threads_working = 0; + // parmap_apply ensures that every working thread get an index in the process_to_run array (through an atomic fetch_and_add), + // and runs the smx_ctx_sysv_resume_parallel function on that index + xbt_parmap_apply(sysv_parmap, (void_f_pvoid_t) smx_ctx_sysv_resume_parallel, + simix_global->process_to_run); +#else + xbt_die("You asked for a parallel execution, but you don't have any threads."); +#endif +} + +/* This function is in charge of running one particular simulated process on the current thread */ +static void smx_ctx_sysv_resume_parallel(smx_process_t simulated_process_to_run) { +#ifdef CONTEXT_THREADS + unsigned long worker_id = __sync_fetch_and_add(&sysv_threads_working, 1); // what is my containing body? + xbt_os_thread_set_specific(sysv_worker_id_key, (void*) worker_id); // Store the number of my containing body in os-thread-specific area + smx_ctx_sysv_t worker_context = (smx_ctx_sysv_t)SIMIX_context_self(); // get my current soul + sysv_workers_context[worker_id] = worker_context; // write down that this soul is hosted in that body (for now) + ucontext_t* worker_stack = &worker_context->uc; // retrieves the system-level info that fuels this soul + + smx_context_t context = simulated_process_to_run->context; // That's the first soul that I should become + SIMIX_context_set_current(context); // write in simix that I switched my soul + swapcontext(worker_stack, &((smx_ctx_sysv_t) context)->uc); // actually do that using the relevant syscall + // No body runs that soul anymore at this point. Instead the current body took the soul of simulated process + // The simulated process wakes back after the call to "SIMIX_context_suspend(self->context);" within smx_process.c::SIMIX_process_yield() + + // From now on, the simulated processes will change their soul with the next soul to execute (in suspend_parallel, below). + // When nobody is to be executed in this scheduling round, the last simulated process will take back the initial soul of the current working thread +#endif +} + +/* This function is called when a simulated process wants to yield back to the maestro in a blocking simcall. + * This naturally occurs within SIMIX_context_suspend(self->context), called from SIMIX_process_yield() + * Actually, it does not really yield back to maestro, but into the next process that must be executed. + * If no one is to be executed, then it yields to the initial soul that was in this working thread (that was saved in resume_parallel). + */ +static void smx_ctx_sysv_suspend_parallel(smx_context_t context) { #ifdef CONTEXT_THREADS /* determine the next context */ - smx_process_t next_work = xbt_parmap_next(sysv_parmap); + smx_process_t next_work = xbt_parmap_next(sysv_parmap); // get the next soul to embody now smx_context_t next_context; - ucontext_t* next_stack; + ucontext_t* next_stack; // will contain the next soul to run, either simulated or initial minion's one - if (next_work != NULL) { - /* there is a next process to resume */ + if (next_work != NULL) { // there is a next soul to embody (ie, a next process to resume) XBT_DEBUG("Run next process"); next_context = next_work->context; - next_stack = &((smx_ctx_sysv_t) next_context)->uc; } else { /* all processes were run, go to the barrier */ XBT_DEBUG("No more processes to run"); - unsigned long worker_id = + unsigned long worker_id = // Get back the identity of my body that was stored when starting the scheduling round (unsigned long) xbt_os_thread_get_specific(sysv_worker_id_key); - next_context = (smx_context_t)sysv_workers_context[worker_id]; - next_stack = &((smx_ctx_sysv_t)next_context)->uc; + next_context = (smx_context_t)sysv_workers_context[worker_id]; // deduce the initial soul of that body + // When given that soul, the body will wait for the next scheduling round } - SIMIX_context_set_current(next_context); - swapcontext(&((smx_ctx_sysv_t) context)->uc, next_stack); -#endif -} - -static void smx_ctx_sysv_resume_parallel(smx_process_t first_process) -{ -#ifdef CONTEXT_THREADS - unsigned long worker_id = __sync_fetch_and_add(&sysv_threads_working, 1); - xbt_os_thread_set_specific(sysv_worker_id_key, (void*) worker_id); - smx_ctx_sysv_t worker_context = (smx_ctx_sysv_t)SIMIX_context_self(); - sysv_workers_context[worker_id] = worker_context; - ucontext_t* worker_stack = &worker_context->uc; + next_stack = &((smx_ctx_sysv_t)next_context)->uc; - smx_context_t context = first_process->context; - SIMIX_context_set_current(context); - swapcontext(worker_stack, &((smx_ctx_sysv_t) context)->uc); -#endif -} - -static void smx_ctx_sysv_runall_parallel(void) -{ -#ifdef CONTEXT_THREADS - sysv_threads_working = 0; - xbt_parmap_apply(sysv_parmap, (void_f_pvoid_t) smx_ctx_sysv_resume_parallel, - simix_global->process_to_run); + SIMIX_context_set_current(next_context); + swapcontext(&((smx_ctx_sysv_t) context)->uc, next_stack); // get that next soul #endif }