Hello
In addition to deprecating the omp_(get|set)_nested() functions and OMP_NESTED
environment variable, OpenMP 5.0 also removes the nest-var ICV altogether,
defining it in terms of the max-active-levels-var ICV instead.
This patch removes the ICV, and implements the handling of
omp_(get|set)_nested() in terms of max-active-levels-var as defined in the spec.
The initial value of max-active-levels-var now depends on the number of items in
OMP_NUM_THREADS and OMP_PROC_BIND as defined in section 2.5.2 of the spec.
OMP_NESTED now changes the value of max-active-levels-var. If OMP_NESTED is
false and OMP_MAX_ACTIVE_LEVELS is > 1, I have opted to use the value specified
by OMP_MAX_ACTIVE_LEVELS, as OMP_NESTED is deprecated in OpenMP 5.0 (the spec
says this is implementation defined in section 6.9).
The default value of max-active-levels-var is implementation defined (section
2.5.2). It was previously set to the maximum supported number, but I think it
should be 1 now, since OMP_NESTED defaults to false on OpenMP 4.5, and this
replicates that behaviour.
This change regresses the testcase libgomp.c/target-5.c because nested-var is
per data environment, while max-active-levels-var is per-device. The change in
semantics causes the test for the nesting setting to fail, because now any
changes to the nesting setting apply to the whole device, and not just to the
current data environment. I just deleted this part of the testing as the test
looks like it is testing per data environment ICVs.
Bootstrapped on x86_64 with no offloading, and libgomp testing carried out with
nvptx offloading with no regressions.
Okay for trunk?
Thanks
Kwok
commit aad8afea37b33b4d5836b2b64be8f4dab6d74509
Author: Kwok Cheung Yeung <k...@codesourcery.com>
Date: Wed Nov 4 15:34:12 2020 -0800
openmp: Retire nest-var ICV for OpenMP 5.0
This removes the nest-var ICV, expressing nesting in terms of the
max-active-levels-var ICV instead.
2020-11-06 Kwok Cheung Yeung <k...@codesourcery.com>
libgomp/
* env.c (gomp_global_icv): Remove nest_var field.
(gomp_max_active_levels_var): Initialize to 1.
(parse_boolean): Return true on success.
(handle_omp_display_env): Express OMP_NESTED in terms of
gomp_max_active_levels_var.
(initialize_env): Set gomp_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
gomp_max_active_levels_var.
(omp_get_nested): Likewise.
* libgomp.h (struct gomp_task_icv): Remove nest_var field.
* parallel.c (gomp_resolve_num_threads): Replace reference
to nest_var with gomp_max_active_levels_var.
* testsuite/libgomp.c/target-5.c: Remove additional options.
(main): Remove references to omp_get_nested and omp_set_nested.
diff --git a/libgomp/env.c b/libgomp/env.c
index ab22525..75d0fe2 100644
--- a/libgomp/env.c
+++ b/libgomp/env.c
@@ -68,12 +68,11 @@ struct gomp_task_icv gomp_global_icv = {
.run_sched_chunk_size = 1,
.default_device_var = 0,
.dyn_var = false,
- .nest_var = false,
.bind_var = omp_proc_bind_false,
.target_data = NULL
};
-unsigned long gomp_max_active_levels_var = gomp_supported_active_levels;
+unsigned long gomp_max_active_levels_var = 1;
bool gomp_cancel_var = false;
enum gomp_target_offload_t gomp_target_offload_var
= GOMP_TARGET_OFFLOAD_DEFAULT;
@@ -959,16 +958,17 @@ parse_spincount (const char *name, unsigned long long
*pvalue)
}
/* 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;
@@ -987,7 +987,11 @@ parse_boolean (const char *name, bool *value)
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. */
@@ -1252,7 +1256,7 @@ handle_omp_display_env (unsigned long stacksize, int
wait_policy)
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_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++)
@@ -1417,16 +1421,11 @@ initialize_env (void)
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))
{
@@ -1451,6 +1450,23 @@ initialize_env (void)
&gomp_bind_var_list_len)
&& gomp_global_icv.bind_var == omp_proc_bind_false)
ignore = true;
+ if (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;
+ }
+ else
+ {
+ bool nested = true;
+
+ /* OMP_NESTED is deprecated in OpenMP 5.0. */
+ if (parse_boolean ("OMP_NESTED", &nested))
+ gomp_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_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
diff --git a/libgomp/icv.c b/libgomp/icv.c
index 8df15e3..f54ccb1 100644
--- a/libgomp/icv.c
+++ b/libgomp/icv.c
@@ -56,15 +56,16 @@ omp_get_dynamic (void)
void
omp_set_nested (int val)
{
- struct gomp_task_icv *icv = gomp_icv (true);
- icv->nest_var = val;
+ if (val)
+ gomp_max_active_levels_var = gomp_supported_active_levels;
+ else if (gomp_max_active_levels_var > 1)
+ gomp_max_active_levels_var = 1;
}
int
omp_get_nested (void)
{
- struct gomp_task_icv *icv = gomp_icv (false);
- return icv->nest_var;
+ return gomp_max_active_levels_var > 1;
}
#pragma GCC diagnostic pop
diff --git a/libgomp/libgomp.h b/libgomp/libgomp.h
index da7ac03..05aa1e4 100644
--- a/libgomp/libgomp.h
+++ b/libgomp/libgomp.h
@@ -428,7 +428,6 @@ struct gomp_task_icv
int default_device_var;
unsigned int thread_limit_var;
bool dyn_var;
- bool nest_var;
char bind_var;
/* Internal ICV. */
struct target_mem_desc *target_data;
diff --git a/libgomp/parallel.c b/libgomp/parallel.c
index 2fe4f573..9629470 100644
--- a/libgomp/parallel.c
+++ b/libgomp/parallel.c
@@ -53,7 +53,7 @@ gomp_resolve_num_threads (unsigned specified, unsigned count)
/* Accelerators with fixed thread counts require this to return 1 for
nested parallel regions. */
#if !defined(__AMDGCN__) && !defined(__nvptx__)
- && !icv->nest_var
+ && gomp_max_active_levels_var <= 1
#endif
)
return 1;
diff --git a/libgomp/testsuite/libgomp.c/target-5.c
b/libgomp/testsuite/libgomp.c/target-5.c
index 21a69ea..ec31f89 100644
--- a/libgomp/testsuite/libgomp.c/target-5.c
+++ b/libgomp/testsuite/libgomp.c/target-5.c
@@ -1,5 +1,3 @@
-/* { dg-additional-options "-Wno-deprecated-declarations" } */
-
#include <omp.h>
#include <stdlib.h>
@@ -7,17 +5,14 @@ int
main ()
{
int d_o = omp_get_dynamic ();
- int n_o = omp_get_nested ();
omp_sched_t s_o;
int c_o;
omp_get_schedule (&s_o, &c_o);
int m_o = omp_get_max_threads ();
omp_set_dynamic (1);
- omp_set_nested (1);
omp_set_schedule (omp_sched_static, 2);
omp_set_num_threads (4);
int d = omp_get_dynamic ();
- int n = omp_get_nested ();
omp_sched_t s;
int c;
omp_get_schedule (&s, &c);
@@ -30,13 +25,11 @@ main ()
int c_c;
omp_get_schedule (&s_c, &c_c);
if (d_o != omp_get_dynamic ()
- || n_o != omp_get_nested ()
|| s_o != s_c
|| c_o != c_c
|| m_o != omp_get_max_threads ())
abort ();
omp_set_dynamic (0);
- omp_set_nested (0);
omp_set_schedule (omp_sched_dynamic, 4);
omp_set_num_threads (2);
if (!omp_is_initial_device ())
@@ -48,7 +41,6 @@ main ()
int c_c;
omp_get_schedule (&s_c, &c_c);
if (d != omp_get_dynamic ()
- || n != omp_get_nested ()
|| s != s_c
|| c != c_c
|| m != omp_get_max_threads ())
@@ -60,13 +52,11 @@ main ()
int c_c;
omp_get_schedule (&s_c, &c_c);
if (d_o != omp_get_dynamic ()
- || n_o != omp_get_nested ()
|| s_o != s_c
|| c_o != c_c
|| m_o != omp_get_max_threads ())
abort ();
omp_set_dynamic (0);
- omp_set_nested (0);
omp_set_schedule (omp_sched_dynamic, 4);
omp_set_num_threads (2);
if (!omp_is_initial_device ())
@@ -76,7 +66,6 @@ main ()
abort ();
omp_get_schedule (&s_c, &c_c);
if (d != omp_get_dynamic ()
- || n != omp_get_nested ()
|| s != s_c
|| c != c_c
|| m != omp_get_max_threads ())
