.run_sched_chunk_size = 1,
.default_device_var = 0,
.dyn_var = false,
- .nest_var = false,
+ .max_active_levels_var = 1,
.bind_var = omp_proc_bind_false,
.target_data = NULL
};
-unsigned long gomp_max_active_levels_var = gomp_supported_active_levels;
bool gomp_cancel_var = false;
enum gomp_target_offload_t gomp_target_offload_var
= GOMP_TARGET_OFFLOAD_DEFAULT;
}
/* Parse a boolean value for environment variable NAME and store the
- result in VALUE. */
+ result in VALUE. Return true if one was present and it was
+ successfully parsed. */
-static void
+static bool
parse_boolean (const char *name, bool *value)
{
const char *env;
env = getenv (name);
if (env == NULL)
- return;
+ return false;
while (isspace ((unsigned char) *env))
++env;
while (isspace ((unsigned char) *env))
++env;
if (*env != '\0')
- gomp_error ("Invalid value for environment variable %s", name);
+ {
+ gomp_error ("Invalid value for environment variable %s", name);
+ return false;
+ }
+ return true;
}
/* Parse the OMP_WAIT_POLICY environment variable and return the value. */
fprintf (stderr, " OMP_DYNAMIC = '%s'\n",
gomp_global_icv.dyn_var ? "TRUE" : "FALSE");
fprintf (stderr, " OMP_NESTED = '%s'\n",
- gomp_global_icv.nest_var ? "TRUE" : "FALSE");
+ gomp_global_icv.max_active_levels_var > 1 ? "TRUE" : "FALSE");
fprintf (stderr, " OMP_NUM_THREADS = '%lu", gomp_global_icv.nthreads_var);
for (i = 1; i < gomp_nthreads_var_list_len; i++)
wait_policy > 0 ? "ACTIVE" : "PASSIVE");
fprintf (stderr, " OMP_THREAD_LIMIT = '%u'\n",
gomp_global_icv.thread_limit_var);
- fprintf (stderr, " OMP_MAX_ACTIVE_LEVELS = '%lu'\n",
- gomp_max_active_levels_var);
+ fprintf (stderr, " OMP_MAX_ACTIVE_LEVELS = '%u'\n",
+ gomp_global_icv.max_active_levels_var);
fprintf (stderr, " OMP_CANCELLATION = '%s'\n",
gomp_cancel_var ? "TRUE" : "FALSE");
initialize_env (void)
{
unsigned long thread_limit_var, stacksize = GOMP_DEFAULT_STACKSIZE;
+ unsigned long max_active_levels_var;
int wait_policy;
/* Do a compile time check that mkomp_h.pl did good job. */
parse_schedule ();
parse_boolean ("OMP_DYNAMIC", &gomp_global_icv.dyn_var);
- parse_boolean ("OMP_NESTED", &gomp_global_icv.nest_var);
parse_boolean ("OMP_CANCELLATION", &gomp_cancel_var);
parse_boolean ("OMP_DISPLAY_AFFINITY", &gomp_display_affinity_var);
parse_int ("OMP_DEFAULT_DEVICE", &gomp_global_icv.default_device_var, true);
parse_target_offload ("OMP_TARGET_OFFLOAD", &gomp_target_offload_var);
parse_int ("OMP_MAX_TASK_PRIORITY", &gomp_max_task_priority_var, true);
- parse_unsigned_long ("OMP_MAX_ACTIVE_LEVELS", &gomp_max_active_levels_var,
- true);
- if (gomp_max_active_levels_var > gomp_supported_active_levels)
- gomp_max_active_levels_var = gomp_supported_active_levels;
gomp_def_allocator = parse_allocator ();
if (parse_unsigned_long ("OMP_THREAD_LIMIT", &thread_limit_var, false))
{
&gomp_bind_var_list_len)
&& gomp_global_icv.bind_var == omp_proc_bind_false)
ignore = true;
+ if (parse_unsigned_long ("OMP_MAX_ACTIVE_LEVELS",
+ &max_active_levels_var, true))
+ gomp_global_icv.max_active_levels_var
+ = (max_active_levels_var > gomp_supported_active_levels)
+ ? gomp_supported_active_levels : max_active_levels_var;
+ else
+ {
+ bool nested = true;
+
+ /* OMP_NESTED is deprecated in OpenMP 5.0. */
+ if (parse_boolean ("OMP_NESTED", &nested))
+ gomp_global_icv.max_active_levels_var
+ = nested ? gomp_supported_active_levels : 1;
+ else if (gomp_nthreads_var_list_len > 1 || gomp_bind_var_list_len > 1)
+ gomp_global_icv.max_active_levels_var = gomp_supported_active_levels;
+ }
/* Make sure OMP_PLACES and GOMP_CPU_AFFINITY env vars are always
parsed if present in the environment. If OMP_PROC_BIND was set
explicitly to false, don't populate places list though. If places
omp_set_nested (int val)
{
struct gomp_task_icv *icv = gomp_icv (true);
- icv->nest_var = val;
+ if (val)
+ icv->max_active_levels_var = gomp_supported_active_levels;
+ else if (icv->max_active_levels_var > 1)
+ icv->max_active_levels_var = 1;
}
int
omp_get_nested (void)
{
struct gomp_task_icv *icv = gomp_icv (false);
- return icv->nest_var;
+ return (icv->max_active_levels_var > 1
+ && icv->max_active_levels_var > omp_get_active_level ());
}
#pragma GCC diagnostic pop
{
if (max_levels >= 0)
{
+ struct gomp_task_icv *icv = gomp_icv (true);
+
if (max_levels <= gomp_supported_active_levels)
- gomp_max_active_levels_var = max_levels;
+ icv->max_active_levels_var = max_levels;
else
- gomp_max_active_levels_var = gomp_supported_active_levels;
+ icv->max_active_levels_var = gomp_supported_active_levels;
}
}
int
omp_get_max_active_levels (void)
{
- return gomp_max_active_levels_var;
+ struct gomp_task_icv *icv = gomp_icv (false);
+ return icv->max_active_levels_var;
}
int
int default_device_var;
unsigned int thread_limit_var;
bool dyn_var;
- bool nest_var;
+ unsigned char max_active_levels_var;
char bind_var;
/* Internal ICV. */
struct target_mem_desc *target_data;
GOMP_TARGET_OFFLOAD_DISABLED
};
-#define gomp_supported_active_levels INT_MAX
+#define gomp_supported_active_levels UCHAR_MAX
extern struct gomp_task_icv gomp_global_icv;
#ifndef HAVE_SYNC_BUILTINS
extern gomp_mutex_t gomp_managed_threads_lock;
#endif
-extern unsigned long gomp_max_active_levels_var;
extern bool gomp_cancel_var;
extern enum gomp_target_offload_t gomp_target_offload_var;
extern int gomp_max_task_priority_var;
enabled, @code{false} otherwise. Here, @code{true} and @code{false}
represent their language-specific counterparts.
-Nested parallel regions may be initialized at startup by the
-@env{OMP_NESTED} environment variable or at runtime using
-@code{omp_set_nested}. If undefined, nested parallel regions are
-disabled by default.
+The state of nested parallel regions at startup depends on several
+environment variables. If @env{OMP_MAX_ACTIVE_LEVELS} is defined
+and is set to greater than one, then nested parallel regions will be
+enabled. If not defined, then the value of the @env{OMP_NESTED}
+environment variable will be followed if defined. If neither are
+defined, then if either @env{OMP_NUM_THREADS} or @env{OMP_PROC_BIND}
+are defined with a list of more than one value, then nested parallel
+regions are enabled. If none of these are defined, then nested parallel
+regions are disabled by default.
+
+Nested parallel regions can be enabled or disabled at runtime using
+@code{omp_set_nested}, or by setting the maximum number of nested
+regions with @code{omp_set_max_active_levels} to one to disable, or
+above one to enable.
@item @emph{C/C++}:
@multitable @columnfractions .20 .80
@end multitable
@item @emph{See also}:
-@ref{omp_set_nested}, @ref{OMP_NESTED}
+@ref{omp_set_max_active_levels}, @ref{omp_set_nested},
+@ref{OMP_MAX_ACTIVE_LEVELS}, @ref{OMP_NESTED}
@item @emph{Reference}:
@uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.11.
equivalent of @code{true} and @code{false}, where @code{true} enables
dynamic adjustment of team sizes and @code{false} disables it.
+Enabling nested parallel regions will also set the maximum number of
+active nested regions to the maximum supported. Disabling nested parallel
+regions will set the maximum number of active nested regions to one.
+
@item @emph{C/C++}:
@multitable @columnfractions .20 .80
@item @emph{Prototype}: @tab @code{void omp_set_nested(int nested);}
@end multitable
@item @emph{See also}:
-@ref{OMP_NESTED}, @ref{omp_get_nested}
+@ref{omp_get_nested}, @ref{omp_set_max_active_levels},
+@ref{OMP_MAX_ACTIVE_LEVELS}, @ref{OMP_NESTED}
@item @emph{Reference}:
@uref{https://www.openmp.org, OpenMP specification v4.5}, Section 3.2.10.
@item @emph{Description}:
Specifies the initial value for the maximum number of nested parallel
regions. The value of this variable shall be a positive integer.
-If undefined, the number of active levels is unlimited.
+If undefined, then if @env{OMP_NESTED} is defined and set to true, or
+if @env{OMP_NUM_THREADS} or @env{OMP_PROC_BIND} are defined and set to
+a list with more than one item, the maximum number of nested parallel
+regions will be initialized to the largest number supported, otherwise
+it will be set to one.
@item @emph{See also}:
-@ref{omp_set_max_active_levels}
+@ref{omp_set_max_active_levels}, @ref{OMP_NESTED}
@item @emph{Reference}:
@uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.9
@item @emph{Description}:
Enable or disable nested parallel regions, i.e., whether team members
are allowed to create new teams. The value of this environment variable
-shall be @code{TRUE} or @code{FALSE}. If undefined, nested parallel
-regions are disabled by default.
+shall be @code{TRUE} or @code{FALSE}. If set to @code{TRUE}, the number
+of maximum active nested regions supported will by default be set to the
+maximum supported, otherwise it will be set to one. If
+@env{OMP_MAX_ACTIVE_LEVELS} is defined, its setting will override this
+setting. If both are undefined, nested parallel regions are enabled if
+@env{OMP_NUM_THREADS} or @env{OMP_PROC_BINDS} are defined to a list with
+more than one item, otherwise they are disabled by default.
@item @emph{See also}:
-@ref{omp_set_nested}
+@ref{omp_set_max_active_levels}, @ref{omp_set_nested}
@item @emph{Reference}:
@uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.6
@item @emph{Description}:
Specifies the default number of threads to use in parallel regions. The
value of this variable shall be a comma-separated list of positive integers;
-the value specified the number of threads to use for the corresponding nested
-level. If undefined one thread per CPU is used.
+the value specifies the number of threads to use for the corresponding nested
+level. Specifying more than one item in the list will automatically enable
+nesting by default. If undefined one thread per CPU is used.
@item @emph{See also}:
-@ref{omp_set_num_threads}
+@ref{omp_set_num_threads}, @ref{OMP_NESTED}
@item @emph{Reference}:
@uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.2
@code{MASTER} the worker threads are in the same place partition as the
master thread. With @code{CLOSE} those are kept close to the master thread
in contiguous place partitions. And with @code{SPREAD} a sparse distribution
-across the place partitions is used.
+across the place partitions is used. Specifying more than one item in the
+list will automatically enable nesting by default.
When undefined, @env{OMP_PROC_BIND} defaults to @code{TRUE} when
@env{OMP_PLACES} or @env{GOMP_CPU_AFFINITY} is set and @code{FALSE} otherwise.
@item @emph{See also}:
-@ref{OMP_PLACES}, @ref{GOMP_CPU_AFFINITY}, @ref{omp_get_proc_bind}
+@ref{omp_get_proc_bind}, @ref{GOMP_CPU_AFFINITY},
+@ref{OMP_NESTED}, @ref{OMP_PLACES}
@item @emph{Reference}:
@uref{https://www.openmp.org, OpenMP specification v4.5}, Section 4.4
/* Accelerators with fixed thread counts require this to return 1 for
nested parallel regions. */
#if !defined(__AMDGCN__) && !defined(__nvptx__)
- && !icv->nest_var
+ && icv->max_active_levels_var <= 1
#endif
)
return 1;
- else if (thr->ts.active_level >= gomp_max_active_levels_var)
+ else if (thr->ts.active_level >= icv->max_active_levels_var)
return 1;
/* If NUM_THREADS not specified, use nthreads_var. */
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