-/* context_sysv - context switching with ucontextes from System V */
+/* context_sysv - context switching with ucontexts from System V */
-/* Copyright (c) 2009, 2010. The SimGrid Team.
+/* Copyright (c) 2009-2015. The SimGrid Team.
* All rights reserved. */
- /* This program is free software; you can redistribute it and/or modify it
- * under the terms of the license (GNU LGPL) which comes with this package. */
+/* This program is free software; you can redistribute it and/or modify it
+ * under the terms of the license (GNU LGPL) which comes with this package. */
#include <stdarg.h>
-#include "smx_context_sysv_private.h"
#include "xbt/parmap.h"
-#include "simix/private.h"
-#include "gras_config.h"
-
-#ifdef HAVE_VALGRIND_VALGRIND_H
-# include <valgrind/valgrind.h>
-#endif /* HAVE_VALGRIND_VALGRIND_H */
+#include "smx_private.h"
+#include "src/internal_config.h"
+#include "src/context_sysv_config.h" /* loads context system definitions */
+#include "mc/mc.h"
#ifdef _XBT_WIN32
-#include "win32_ucontext.h"
+# include <xbt/win32_ucontext.h> /* context relative declarations */
#else
-#include "ucontext.h"
+# include <ucontext.h> /* context relative declarations */
#endif
XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(simix_context);
+typedef struct s_smx_ctx_sysv {
+ s_smx_ctx_base_t super; /* Fields of super implementation */
+ ucontext_t uc; /* the ucontext that executes the code */
+ char *stack; /* the thread stack */
+} s_smx_ctx_sysv_t, *smx_ctx_sysv_t;
+
#ifdef CONTEXT_THREADS
-static xbt_parmap_t parmap;
+static xbt_parmap_t sysv_parmap;
+static smx_ctx_sysv_t* sysv_workers_context; /* space to save the worker's context in each thread */
+static unsigned long sysv_threads_working; /* number of threads that have started their work */
+static xbt_os_thread_key_t sysv_worker_id_key; /* thread-specific storage for the thread id */
#endif
+static unsigned long sysv_process_index = 0; /* index of the next process to run in the
+ * list of runnable processes */
+static smx_ctx_sysv_t sysv_maestro_context;
+static int smx_ctx_sysv_factory_finalize(smx_context_factory_t *factory);
+static void smx_ctx_sysv_free(smx_context_t context);
static smx_context_t
smx_ctx_sysv_create_context(xbt_main_func_t code, int argc, char **argv,
- void_pfn_smxprocess_t cleanup_func, void* data);
+ void_pfn_smxprocess_t cleanup_func, smx_process_t process);
static void smx_ctx_sysv_wrapper(int count, ...);
-/* This is a bit paranoid about SIZEOF_VOIDP not being a multiple of SIZEOF_INT,
- * but it doesn't harm. */
-#define CTX_ADDR_LEN (SIZEOF_VOIDP / SIZEOF_INT + !!(SIZEOF_VOIDP % SIZEOF_INT))
-union u_ctx_addr {
- void *addr;
- int intv[CTX_ADDR_LEN];
-};
-#if (CTX_ADDR_LEN == 1)
-# define CTX_ADDR_SPLIT(u) (u).intv[0]
-#elif (CTX_ADDR_LEN == 2)
-# define CTX_ADDR_SPLIT(u) (u).intv[0], (u).intv[1]
-#else
-# error Your architecture is not supported yet
-#endif
+static void smx_ctx_sysv_stop_serial(smx_context_t context);
+static void smx_ctx_sysv_suspend_serial(smx_context_t context);
+static void smx_ctx_sysv_resume_serial(smx_process_t first_process);
+static void smx_ctx_sysv_runall_serial(void);
+
+static void smx_ctx_sysv_stop_parallel(smx_context_t context);
+static void smx_ctx_sysv_suspend_parallel(smx_context_t context);
+static void smx_ctx_sysv_resume_parallel(smx_process_t first_process);
+static void smx_ctx_sysv_runall_parallel(void);
+
+/* This is a bit paranoid about sizeof(smx_ctx_sysv_t) not being a multiple of
+ * sizeof(int), but it doesn't harm. */
+#define CTX_ADDR_LEN \
+ (sizeof(smx_ctx_sysv_t) / sizeof(int) + \
+ !!(sizeof(smx_ctx_sysv_t) % sizeof(int)))
void SIMIX_ctx_sysv_factory_init(smx_context_factory_t *factory)
{
(*factory)->create_context = smx_ctx_sysv_create_context;
/* Do not overload that method (*factory)->finalize */
(*factory)->free = smx_ctx_sysv_free;
- (*factory)->stop = smx_ctx_sysv_stop;
- (*factory)->suspend = smx_ctx_sysv_suspend;
(*factory)->name = "smx_sysv_context_factory";
if (SIMIX_context_is_parallel()) {
-#ifdef CONTEXT_THREADS /* To use parallel ucontexts a thread pool is needed */
- parmap = xbt_parmap_new(2);
+#ifdef CONTEXT_THREADS /* To use parallel ucontexts a thread pool is needed */
+ int nthreads = SIMIX_context_get_nthreads();
+ sysv_parmap = xbt_parmap_new(nthreads, SIMIX_context_get_parallel_mode());
+ sysv_workers_context = xbt_new(smx_ctx_sysv_t, nthreads);
+ sysv_maestro_context = NULL;
+ xbt_os_thread_key_create(&sysv_worker_id_key);
+ (*factory)->stop = smx_ctx_sysv_stop_parallel;
+ (*factory)->suspend = smx_ctx_sysv_suspend_parallel;
(*factory)->runall = smx_ctx_sysv_runall_parallel;
- (*factory)->self = smx_ctx_sysv_self_parallel;
#else
THROWF(arg_error, 0, "No thread support for parallel context execution");
#endif
- }else{
- (*factory)->runall = smx_ctx_sysv_runall;
+ } else {
+ (*factory)->stop = smx_ctx_sysv_stop_serial;
+ (*factory)->suspend = smx_ctx_sysv_suspend_serial;
+ (*factory)->runall = smx_ctx_sysv_runall_serial;
}
}
-int smx_ctx_sysv_factory_finalize(smx_context_factory_t *factory)
+static int smx_ctx_sysv_factory_finalize(smx_context_factory_t *factory)
{
#ifdef CONTEXT_THREADS
- if(parmap)
- xbt_parmap_destroy(parmap);
+ if (sysv_parmap)
+ xbt_parmap_destroy(sysv_parmap);
+ xbt_free(sysv_workers_context);
#endif
return smx_ctx_base_factory_finalize(factory);
}
-smx_context_t
-smx_ctx_sysv_create_context_sized(size_t size, xbt_main_func_t code,
- int argc, char **argv,
- void_pfn_smxprocess_t cleanup_func,
- void *data)
+static smx_context_t
+smx_ctx_sysv_create_context(xbt_main_func_t code, int argc, char **argv,
+ void_pfn_smxprocess_t cleanup_func,
+ smx_process_t process)
{
- union u_ctx_addr ctx_addr;
+ int ctx_addr[CTX_ADDR_LEN];
smx_ctx_sysv_t context =
- (smx_ctx_sysv_t) smx_ctx_base_factory_create_context_sized(size,
- code,
- argc,
- argv,
- cleanup_func,
- data);
-
- /* If the user provided a function for the process then use it
- otherwise is the context for maestro */
+ (smx_ctx_sysv_t) smx_ctx_base_factory_create_context_sized(
+ sizeof(s_smx_ctx_sysv_t),
+ code,
+ argc,
+ argv,
+ cleanup_func,
+ process);
+
+ /* if the user provided a function for the process then use it,
+ otherwise it is the context for maestro */
if (code) {
- int res;
- res = getcontext(&(context->uc));
- xbt_assert(res == 0,
- "Error in context saving: %d (%s)", errno,
- strerror(errno));
+ context->stack = SIMIX_context_stack_new();
+ getcontext(&(context->uc));
context->uc.uc_link = NULL;
context->uc.uc_stack.ss_sp =
- pth_skaddr_makecontext(context->stack, smx_context_stack_size);
+ pth_skaddr_makecontext(context->stack, smx_context_usable_stack_size);
context->uc.uc_stack.ss_size =
- pth_sksize_makecontext(context->stack, smx_context_stack_size);
-
-#ifdef HAVE_VALGRIND_VALGRIND_H
- context->valgrind_stack_id =
- VALGRIND_STACK_REGISTER(context->uc.uc_stack.ss_sp,
- ((char *) context->uc.uc_stack.ss_sp) +
- context->uc.uc_stack.ss_size);
-#endif /* HAVE_VALGRIND_VALGRIND_H */
- ctx_addr.addr = context;
- makecontext(&context->uc, (void (*)())smx_ctx_sysv_wrapper,
- CTX_ADDR_LEN, CTX_ADDR_SPLIT(ctx_addr));
- }else{
- maestro_context = context;
+ pth_sksize_makecontext(context->stack, smx_context_usable_stack_size);
+
+ memcpy(ctx_addr, &context, sizeof(smx_ctx_sysv_t));
+ switch (CTX_ADDR_LEN) {
+ case 1:
+ makecontext(&context->uc, (void (*)())smx_ctx_sysv_wrapper,
+ 1, ctx_addr[0]);
+ break;
+ case 2:
+ makecontext(&context->uc, (void (*)())smx_ctx_sysv_wrapper,
+ 2, ctx_addr[0], ctx_addr[1]);
+ break;
+ default:
+ xbt_die("Ucontexts are not supported on this arch yet (addr len = %zu/%zu = %zu)",
+ sizeof(smx_ctx_sysv_t), sizeof(int), CTX_ADDR_LEN);
+ }
+ } else {
+ if (process != NULL && sysv_maestro_context == NULL)
+ sysv_maestro_context = context;
}
- return (smx_context_t) context;
-
-}
-
-static smx_context_t
-smx_ctx_sysv_create_context(xbt_main_func_t code, int argc, char **argv,
- void_pfn_smxprocess_t cleanup_func,
- void *data)
-{
-
- return smx_ctx_sysv_create_context_sized(sizeof(s_smx_ctx_sysv_t) + smx_context_stack_size,
- code, argc, argv, cleanup_func,
- data);
+#ifdef HAVE_MC
+ if (MC_is_active() && code) {
+ MC_register_stack_area(context->stack, ((smx_context_t)context)->process,
+ &(context->uc), smx_context_usable_stack_size);
+ }
+#endif
+ return (smx_context_t) context;
}
-void smx_ctx_sysv_free(smx_context_t context)
+static void smx_ctx_sysv_free(smx_context_t context)
{
if (context) {
-
-#ifdef HAVE_VALGRIND_VALGRIND_H
- VALGRIND_STACK_DEREGISTER(((smx_ctx_sysv_t)
- context)->valgrind_stack_id);
-#endif /* HAVE_VALGRIND_VALGRIND_H */
-
+ SIMIX_context_stack_delete(((smx_ctx_sysv_t)context)->stack);
}
smx_ctx_base_free(context);
}
-void smx_ctx_sysv_stop(smx_context_t context)
-{
- smx_ctx_base_stop(context);
- smx_ctx_sysv_suspend(context);
-}
-
-void smx_ctx_sysv_wrapper(int first, ...)
+static void smx_ctx_sysv_wrapper(int first, ...)
{
- union u_ctx_addr ctx_addr;
+ int ctx_addr[CTX_ADDR_LEN];
smx_ctx_sysv_t context;
- ctx_addr.intv[0] = first;
+ ctx_addr[0] = first;
if (CTX_ADDR_LEN > 1) {
va_list ap;
int i;
va_start(ap, first);
- for(i = 1; i < CTX_ADDR_LEN; i++)
- ctx_addr.intv[i] = va_arg(ap, int);
+ for (i = 1; i < CTX_ADDR_LEN; i++)
+ ctx_addr[i] = va_arg(ap, int);
va_end(ap);
}
- context = ctx_addr.addr;
+ memcpy(&context, ctx_addr, sizeof(smx_ctx_sysv_t));
(context->super.code) (context->super.argc, context->super.argv);
- smx_ctx_sysv_stop((smx_context_t) context);
+ simix_global->context_factory->stop((smx_context_t) context);
}
-void smx_ctx_sysv_suspend(smx_context_t context)
+static void smx_ctx_sysv_stop_serial(smx_context_t context)
{
- SIMIX_context_set_current((smx_context_t) maestro_context);
- int rv;
- rv = swapcontext(&((smx_ctx_sysv_t) context)->uc, &((smx_ctx_sysv_t)context)->old_uc);
+ smx_ctx_base_stop(context);
+ smx_ctx_sysv_suspend_serial(context);
+}
- xbt_assert((rv == 0), "Context swapping failure");
+static void smx_ctx_sysv_suspend_serial(smx_context_t context)
+{
+ /* determine the next context */
+ smx_context_t next_context;
+ unsigned long int i = sysv_process_index++;
+
+ if (i < xbt_dynar_length(simix_global->process_to_run)) {
+ /* execute the next process */
+ XBT_DEBUG("Run next process");
+ next_context = xbt_dynar_get_as(
+ simix_global->process_to_run,i, smx_process_t)->context;
+ }
+ else {
+ /* all processes were run, return to maestro */
+ XBT_DEBUG("No more process to run");
+ next_context = (smx_context_t) sysv_maestro_context;
+ }
+ SIMIX_context_set_current(next_context);
+ swapcontext(&((smx_ctx_sysv_t) context)->uc,
+ &((smx_ctx_sysv_t) next_context)->uc);
}
-void smx_ctx_sysv_resume(smx_context_t context)
+static void smx_ctx_sysv_resume_serial(smx_process_t first_process)
{
+ smx_context_t context = first_process->context;
SIMIX_context_set_current(context);
- int rv;
- rv = swapcontext(&((smx_ctx_sysv_t)context)->old_uc, &((smx_ctx_sysv_t) context)->uc);
-
- xbt_assert((rv == 0), "Context swapping failure");
+ swapcontext(&sysv_maestro_context->uc,
+ &((smx_ctx_sysv_t) context)->uc);
}
-void smx_ctx_sysv_runall(xbt_dynar_t processes)
+static void smx_ctx_sysv_runall_serial(void)
{
- smx_process_t process;
- unsigned int cursor;
+ smx_process_t first_process =
+ xbt_dynar_get_as(simix_global->process_to_run, 0, smx_process_t);
+ sysv_process_index = 1;
- xbt_dynar_foreach(processes, cursor, process) {
- XBT_DEBUG("Schedule item %u of %lu",cursor,xbt_dynar_length(processes));
- smx_ctx_sysv_resume(process->context);
- }
+ /* execute the first process */
+ smx_ctx_sysv_resume_serial(first_process);
}
-void smx_ctx_sysv_resume_parallel(smx_process_t process)
+static void smx_ctx_sysv_stop_parallel(smx_context_t context)
{
- smx_context_t context = process->context;
- SIMIX_context_set_current((smx_context_t) context);
- int rv;
- rv = swapcontext(&((smx_ctx_sysv_t)context)->old_uc, &((smx_ctx_sysv_t) context)->uc);
- SIMIX_context_set_current((smx_context_t) maestro_context);
+ smx_ctx_base_stop(context);
+ smx_ctx_sysv_suspend_parallel(context);
+}
- xbt_assert((rv == 0), "Context swapping failure");
+/* 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
}
-void smx_ctx_sysv_runall_parallel(xbt_dynar_t processes)
-{
+/* 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
- xbt_parmap_apply(parmap, (void_f_pvoid_t)smx_ctx_sysv_resume_parallel, processes);
+ 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
}
-smx_context_t smx_ctx_sysv_self_parallel(void)
-{
- /*smx_context_t self_context = (smx_context_t) xbt_os_thread_get_extra_data();
- return self_context ? self_context : (smx_context_t) maestro_context;*/
- return SIMIX_context_get_current();
+/* 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); // get the next soul to embody now
+ smx_context_t next_context;
+ 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 soul to embody (ie, a next process to resume)
+ XBT_DEBUG("Run next process");
+ next_context = next_work->context;
+ }
+ else {
+ /* all processes were run, go to the barrier */
+ XBT_DEBUG("No more processes to run");
+ 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]; // 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); // get that next soul
+#endif
}
