From f9c6777834b0f2a277966c3e6725600d52619f43 Mon Sep 17 00:00:00 2001 From: Martin Quinson Date: Sun, 18 May 2014 19:02:27 +0200 Subject: [PATCH 1/1] greatly improve the documentation of the parallel execution in simix --- src/simix/smx_context_sysv.c | 43 ++++++++++++++++++++---------------- 1 file changed, 24 insertions(+), 19 deletions(-) diff --git a/src/simix/smx_context_sysv.c b/src/simix/smx_context_sysv.c index cb5b022074..c3e5ecac0f 100644 --- a/src/simix/smx_context_sysv.c +++ b/src/simix/smx_context_sysv.c @@ -244,42 +244,47 @@ 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 } + next_stack = &((smx_ctx_sysv_t)next_context)->uc; + SIMIX_context_set_current(next_context); - swapcontext(&((smx_ctx_sysv_t) context)->uc, next_stack); + swapcontext(&((smx_ctx_sysv_t) context)->uc, next_stack); // get that next soul #endif } -static void smx_ctx_sysv_resume_parallel(smx_process_t first_process) +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); - 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; - - smx_context_t context = first_process->context; - SIMIX_context_set_current(context); - swapcontext(worker_stack, &((smx_ctx_sysv_t) context)->uc); + 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, above). + // 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 } -- 2.20.1