openmp: Retire nest-var ICV for OpenMP 5.1
This removes the nest-var ICV, expressing nesting in terms of the max-active-levels-var ICV instead. The max-active-levels-var ICV is now per data environment rather than per device. 2020-11-18 Kwok Cheung Yeung <kcy@codesourcery.com> libgomp/ * env.c (gomp_global_icv): Remove nest_var field. Add max_active_levels_var field. (gomp_max_active_levels_var): Remove. (parse_boolean): Return true on success. (handle_omp_display_env): Express OMP_NESTED in terms of max_active_levels_var. Change format specifier for max_active_levels_var. (initialize_env): Set max_active_levels_var from OMP_MAX_ACTIVE_LEVELS, OMP_NESTED, OMP_NUM_THREADS and OMP_PROC_BIND. * icv.c (omp_set_nested): Express in terms of max_active_levels_var. (omp_get_nested): Likewise. (omp_set_max_active_levels): Use max_active_levels_var field instead of gomp_max_active_levels_var. (omp_get_max_active_levels): Likewise. * libgomp.h (struct gomp_task_icv): Remove nest_var field. Add max_active_levels_var field. (gomp_supported_active_levels): Set to UCHAR_MAX. (gomp_max_active_levels_var): Delete. * libgomp.texi (omp_get_nested): Update documentation. (omp_set_nested): Likewise. (OMP_MAX_ACTIVE_LEVELS): Likewise. (OMP_NESTED): Likewise. (OMP_NUM_THREADS): Likewise. (OMP_PROC_BIND): Likewise. * parallel.c (gomp_resolve_num_threads): Replace reference to nest_var with max_active_levels_var. Use max_active_levels_var field instead of gomp_max_active_levels_var.
This commit is contained in:
Kwok Cheung Yeung
parent
965e0cc371
commit
6fae7eda96
@ -68,12 +68,11 @@ struct gomp_task_icv gomp_global_icv = {
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.run_sched_chunk_size = 1,
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.default_device_var = 0,
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.dyn_var = false,
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.nest_var = false,
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.max_active_levels_var = 1,
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.bind_var = omp_proc_bind_false,
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.target_data = NULL
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};
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unsigned long gomp_max_active_levels_var = gomp_supported_active_levels;
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bool gomp_cancel_var = false;
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enum gomp_target_offload_t gomp_target_offload_var
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= GOMP_TARGET_OFFLOAD_DEFAULT;
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@ -959,16 +958,17 @@ parse_spincount (const char *name, unsigned long long *pvalue)
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}
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/* Parse a boolean value for environment variable NAME and store the
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result in VALUE. */
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result in VALUE. Return true if one was present and it was
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successfully parsed. */
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static void
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static bool
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parse_boolean (const char *name, bool *value)
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{
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const char *env;
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env = getenv (name);
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if (env == NULL)
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return;
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return false;
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while (isspace ((unsigned char) *env))
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++env;
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@ -987,7 +987,11 @@ parse_boolean (const char *name, bool *value)
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while (isspace ((unsigned char) *env))
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++env;
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if (*env != '\0')
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gomp_error ("Invalid value for environment variable %s", name);
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{
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gomp_error ("Invalid value for environment variable %s", name);
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return false;
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}
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return true;
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}
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/* Parse the OMP_WAIT_POLICY environment variable and return the value. */
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@ -1252,7 +1256,7 @@ handle_omp_display_env (unsigned long stacksize, int wait_policy)
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fprintf (stderr, " OMP_DYNAMIC = '%s'\n",
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gomp_global_icv.dyn_var ? "TRUE" : "FALSE");
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fprintf (stderr, " OMP_NESTED = '%s'\n",
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gomp_global_icv.nest_var ? "TRUE" : "FALSE");
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gomp_global_icv.max_active_levels_var > 1 ? "TRUE" : "FALSE");
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fprintf (stderr, " OMP_NUM_THREADS = '%lu", gomp_global_icv.nthreads_var);
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for (i = 1; i < gomp_nthreads_var_list_len; i++)
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@ -1344,8 +1348,8 @@ handle_omp_display_env (unsigned long stacksize, int wait_policy)
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wait_policy > 0 ? "ACTIVE" : "PASSIVE");
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fprintf (stderr, " OMP_THREAD_LIMIT = '%u'\n",
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gomp_global_icv.thread_limit_var);
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fprintf (stderr, " OMP_MAX_ACTIVE_LEVELS = '%lu'\n",
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gomp_max_active_levels_var);
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fprintf (stderr, " OMP_MAX_ACTIVE_LEVELS = '%u'\n",
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gomp_global_icv.max_active_levels_var);
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fprintf (stderr, " OMP_CANCELLATION = '%s'\n",
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gomp_cancel_var ? "TRUE" : "FALSE");
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@ -1410,6 +1414,7 @@ static void __attribute__((constructor))
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initialize_env (void)
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{
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unsigned long thread_limit_var, stacksize = GOMP_DEFAULT_STACKSIZE;
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unsigned long max_active_levels_var;
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int wait_policy;
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/* Do a compile time check that mkomp_h.pl did good job. */
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@ -1417,16 +1422,11 @@ initialize_env (void)
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parse_schedule ();
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parse_boolean ("OMP_DYNAMIC", &gomp_global_icv.dyn_var);
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parse_boolean ("OMP_NESTED", &gomp_global_icv.nest_var);
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parse_boolean ("OMP_CANCELLATION", &gomp_cancel_var);
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parse_boolean ("OMP_DISPLAY_AFFINITY", &gomp_display_affinity_var);
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parse_int ("OMP_DEFAULT_DEVICE", &gomp_global_icv.default_device_var, true);
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parse_target_offload ("OMP_TARGET_OFFLOAD", &gomp_target_offload_var);
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parse_int ("OMP_MAX_TASK_PRIORITY", &gomp_max_task_priority_var, true);
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parse_unsigned_long ("OMP_MAX_ACTIVE_LEVELS", &gomp_max_active_levels_var,
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true);
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if (gomp_max_active_levels_var > gomp_supported_active_levels)
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gomp_max_active_levels_var = gomp_supported_active_levels;
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gomp_def_allocator = parse_allocator ();
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if (parse_unsigned_long ("OMP_THREAD_LIMIT", &thread_limit_var, false))
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{
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@ -1451,6 +1451,22 @@ initialize_env (void)
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&gomp_bind_var_list_len)
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&& gomp_global_icv.bind_var == omp_proc_bind_false)
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ignore = true;
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if (parse_unsigned_long ("OMP_MAX_ACTIVE_LEVELS",
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&max_active_levels_var, true))
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gomp_global_icv.max_active_levels_var
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= (max_active_levels_var > gomp_supported_active_levels)
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? gomp_supported_active_levels : max_active_levels_var;
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else
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{
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bool nested = true;
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/* OMP_NESTED is deprecated in OpenMP 5.0. */
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if (parse_boolean ("OMP_NESTED", &nested))
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gomp_global_icv.max_active_levels_var
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= nested ? gomp_supported_active_levels : 1;
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else if (gomp_nthreads_var_list_len > 1 || gomp_bind_var_list_len > 1)
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gomp_global_icv.max_active_levels_var = gomp_supported_active_levels;
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}
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/* Make sure OMP_PLACES and GOMP_CPU_AFFINITY env vars are always
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parsed if present in the environment. If OMP_PROC_BIND was set
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explicitly to false, don't populate places list though. If places
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@ -57,14 +57,18 @@ void
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omp_set_nested (int val)
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{
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struct gomp_task_icv *icv = gomp_icv (true);
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icv->nest_var = val;
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if (val)
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icv->max_active_levels_var = gomp_supported_active_levels;
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else if (icv->max_active_levels_var > 1)
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icv->max_active_levels_var = 1;
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}
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int
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omp_get_nested (void)
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{
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struct gomp_task_icv *icv = gomp_icv (false);
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return icv->nest_var;
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return (icv->max_active_levels_var > 1
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&& icv->max_active_levels_var > omp_get_active_level ());
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}
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#pragma GCC diagnostic pop
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@ -120,17 +124,20 @@ omp_set_max_active_levels (int max_levels)
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{
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if (max_levels >= 0)
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{
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struct gomp_task_icv *icv = gomp_icv (true);
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if (max_levels <= gomp_supported_active_levels)
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gomp_max_active_levels_var = max_levels;
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icv->max_active_levels_var = max_levels;
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else
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gomp_max_active_levels_var = gomp_supported_active_levels;
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icv->max_active_levels_var = gomp_supported_active_levels;
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}
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}
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int
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omp_get_max_active_levels (void)
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{
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return gomp_max_active_levels_var;
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struct gomp_task_icv *icv = gomp_icv (false);
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return icv->max_active_levels_var;
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}
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int
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@ -428,7 +428,7 @@ struct gomp_task_icv
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int default_device_var;
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unsigned int thread_limit_var;
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bool dyn_var;
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bool nest_var;
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unsigned char max_active_levels_var;
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char bind_var;
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/* Internal ICV. */
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struct target_mem_desc *target_data;
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@ -441,13 +441,12 @@ enum gomp_target_offload_t
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GOMP_TARGET_OFFLOAD_DISABLED
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};
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#define gomp_supported_active_levels INT_MAX
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#define gomp_supported_active_levels UCHAR_MAX
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extern struct gomp_task_icv gomp_global_icv;
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#ifndef HAVE_SYNC_BUILTINS
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extern gomp_mutex_t gomp_managed_threads_lock;
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#endif
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extern unsigned long gomp_max_active_levels_var;
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extern bool gomp_cancel_var;
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extern enum gomp_target_offload_t gomp_target_offload_var;
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extern int gomp_max_task_priority_var;
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@ -487,10 +487,20 @@ This function returns @code{true} if nested parallel regions are
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enabled, @code{false} otherwise. Here, @code{true} and @code{false}
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represent their language-specific counterparts.
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Nested parallel regions may be initialized at startup by the
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@env{OMP_NESTED} environment variable or at runtime using
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@code{omp_set_nested}. If undefined, nested parallel regions are
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disabled by default.
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The state of nested parallel regions at startup depends on several
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environment variables. If @env{OMP_MAX_ACTIVE_LEVELS} is defined
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and is set to greater than one, then nested parallel regions will be
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enabled. If not defined, then the value of the @env{OMP_NESTED}
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environment variable will be followed if defined. If neither are
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defined, then if either @env{OMP_NUM_THREADS} or @env{OMP_PROC_BIND}
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are defined with a list of more than one value, then nested parallel
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regions are enabled. If none of these are defined, then nested parallel
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regions are disabled by default.
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Nested parallel regions can be enabled or disabled at runtime using
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@code{omp_set_nested}, or by setting the maximum number of nested
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regions with @code{omp_set_max_active_levels} to one to disable, or
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above one to enable.
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@item @emph{C/C++}:
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@multitable @columnfractions .20 .80
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@ -503,7 +513,8 @@ disabled by default.
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@end multitable
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@item @emph{See also}:
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@ref{omp_set_nested}, @ref{OMP_NESTED}
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@ref{omp_set_max_active_levels}, @ref{omp_set_nested},
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@ref{OMP_MAX_ACTIVE_LEVELS}, @ref{OMP_NESTED}
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@item @emph{Reference}:
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@uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.11.
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@ -964,6 +975,10 @@ are allowed to create new teams. The function takes the language-specific
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equivalent of @code{true} and @code{false}, where @code{true} enables
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dynamic adjustment of team sizes and @code{false} disables it.
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Enabling nested parallel regions will also set the maximum number of
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active nested regions to the maximum supported. Disabling nested parallel
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regions will set the maximum number of active nested regions to one.
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@item @emph{C/C++}:
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@multitable @columnfractions .20 .80
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@item @emph{Prototype}: @tab @code{void omp_set_nested(int nested);}
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@ -976,7 +991,8 @@ dynamic adjustment of team sizes and @code{false} disables it.
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@end multitable
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@item @emph{See also}:
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@ref{OMP_NESTED}, @ref{omp_get_nested}
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@ref{omp_get_nested}, @ref{omp_set_max_active_levels},
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@ref{OMP_MAX_ACTIVE_LEVELS}, @ref{OMP_NESTED}
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@item @emph{Reference}:
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@uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.10.
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@ -1502,10 +1518,14 @@ disabled by default.
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@item @emph{Description}:
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Specifies the initial value for the maximum number of nested parallel
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regions. The value of this variable shall be a positive integer.
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If undefined, the number of active levels is unlimited.
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If undefined, then if @env{OMP_NESTED} is defined and set to true, or
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if @env{OMP_NUM_THREADS} or @env{OMP_PROC_BIND} are defined and set to
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a list with more than one item, the maximum number of nested parallel
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regions will be initialized to the largest number supported, otherwise
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it will be set to one.
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@item @emph{See also}:
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@ref{omp_set_max_active_levels}
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@ref{omp_set_max_active_levels}, @ref{OMP_NESTED}
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@item @emph{Reference}:
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@uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.9
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@ -1541,11 +1561,16 @@ integer, and zero is allowed. If undefined, the default priority is
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@item @emph{Description}:
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Enable or disable nested parallel regions, i.e., whether team members
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are allowed to create new teams. The value of this environment variable
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shall be @code{TRUE} or @code{FALSE}. If undefined, nested parallel
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regions are disabled by default.
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shall be @code{TRUE} or @code{FALSE}. If set to @code{TRUE}, the number
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of maximum active nested regions supported will by default be set to the
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maximum supported, otherwise it will be set to one. If
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@env{OMP_MAX_ACTIVE_LEVELS} is defined, its setting will override this
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setting. If both are undefined, nested parallel regions are enabled if
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@env{OMP_NUM_THREADS} or @env{OMP_PROC_BINDS} are defined to a list with
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more than one item, otherwise they are disabled by default.
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@item @emph{See also}:
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@ref{omp_set_nested}
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@ref{omp_set_max_active_levels}, @ref{omp_set_nested}
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@item @emph{Reference}:
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@uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.6
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@ -1561,11 +1586,12 @@ regions are disabled by default.
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@item @emph{Description}:
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Specifies the default number of threads to use in parallel regions. The
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value of this variable shall be a comma-separated list of positive integers;
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the value specified the number of threads to use for the corresponding nested
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level. If undefined one thread per CPU is used.
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the value specifies the number of threads to use for the corresponding nested
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level. Specifying more than one item in the list will automatically enable
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nesting by default. If undefined one thread per CPU is used.
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@item @emph{See also}:
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@ref{omp_set_num_threads}
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@ref{omp_set_num_threads}, @ref{OMP_NESTED}
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@item @emph{Reference}:
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@uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.2
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@ -1586,13 +1612,15 @@ the thread affinity policy for the corresponding nesting level. With
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@code{MASTER} the worker threads are in the same place partition as the
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master thread. With @code{CLOSE} those are kept close to the master thread
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in contiguous place partitions. And with @code{SPREAD} a sparse distribution
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across the place partitions is used.
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across the place partitions is used. Specifying more than one item in the
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list will automatically enable nesting by default.
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When undefined, @env{OMP_PROC_BIND} defaults to @code{TRUE} when
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@env{OMP_PLACES} or @env{GOMP_CPU_AFFINITY} is set and @code{FALSE} otherwise.
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@item @emph{See also}:
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@ref{OMP_PLACES}, @ref{GOMP_CPU_AFFINITY}, @ref{omp_get_proc_bind}
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@ref{omp_get_proc_bind}, @ref{GOMP_CPU_AFFINITY},
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@ref{OMP_NESTED}, @ref{OMP_PLACES}
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@item @emph{Reference}:
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@uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.4
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@ -53,11 +53,11 @@ gomp_resolve_num_threads (unsigned specified, unsigned count)
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/* Accelerators with fixed thread counts require this to return 1 for
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nested parallel regions. */
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#if !defined(__AMDGCN__) && !defined(__nvptx__)
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&& !icv->nest_var
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&& icv->max_active_levels_var <= 1
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#endif
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)
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return 1;
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else if (thr->ts.active_level >= gomp_max_active_levels_var)
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else if (thr->ts.active_level >= icv->max_active_levels_var)
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return 1;
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/* If NUM_THREADS not specified, use nthreads_var. */
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