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Re: [gomp4] Redesign oacc_parallel launch API
- From: Nathan Sidwell <nathan at acm dot org>
- To: Thomas Schwinge <thomas at codesourcery dot com>
- Cc: Jakub Jelinek <jakub at redhat dot com>, GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Wed, 29 Jul 2015 17:45:32 -0400
- Subject: Re: [gomp4] Redesign oacc_parallel launch API
- Authentication-results: sourceware.org; auth=none
- References: <55B7B332 dot 1010603 at acm dot org> <87a8ufqpxg dot fsf at kepler dot schwinge dot homeip dot net> <55B8C619 dot 7040807 at acm dot org>
On 07/29/15 08:24, Nathan Sidwell wrote:
On 07/29/15 05:22, Thomas Schwinge wrote:
Likewise for the other torture testing flags.
Investigating ... (I've seen those failures be intermittent)
Interestingly the fails go away with an unoptimized libgomp. I've observed
something vaguely like that before. The observed failure mode was getting stuck
inside the driver library opening the device. Which is very strange.
Anyway, I've committed the attached to gomp4 branch, which separates the ASYNC
and WAIT tags, for a slightly better interface. It doesn't fixup the failure
thought. Still thinking about that.
nathan
2015-07-29 Nathan Sidwell <nathan@codesourcery.com>
include/
* gomp-constants.h (GOMP_LAUNCH_ASYNC_WAIT): Replace with ...
(GOMP_LAUNCH_ASYNC, GOMP_LAUNCH_WAIT): ... these.
(GOMP_LAUNCH_OP_MAX): New.
libgomp/
* plugin/plugin-nvptx.c (nvptx_wait): Add debug print.
* oacc-parallel.c (GOACC_parallel_keyed): Process separate ASYNC
and WAIT tags.
(GOACC_parallel): Adjust forwarding.
gcc/
* omp-low.c (expand_omp_target): Emit separate ASYNC and WAIT tags.
Index: gcc/omp-low.c
===================================================================
--- gcc/omp-low.c (revision 226346)
+++ gcc/omp-low.c (working copy)
@@ -9875,23 +9875,35 @@ expand_omp_target (struct omp_region *re
integer_type_node,
build_int_cst (integer_type_node,
GOMP_ASYNC_SYNC));
- if (t_async && !tagging)
+ if (tagging && t_async)
{
- args.safe_push (t_async);
- t_async = NULL_TREE;
+ unsigned HOST_WIDE_INT i_async;
+
+ if (TREE_CODE (t_async) == INTEGER_CST)
+ {
+ /* See if we can pack the async arg in to the tag's
+ operand. */
+ i_async = TREE_INT_CST_LOW (t_async);
+
+ if (i_async < GOMP_LAUNCH_OP_MAX)
+ t_async = NULL_TREE;
+ }
+ if (t_async)
+ i_async = GOMP_LAUNCH_OP_MAX;
+ args.safe_push (oacc_launch_pack
+ (GOMP_LAUNCH_ASYNC, NULL_TREE, i_async));
}
+ if (t_async)
+ args.safe_push (t_async);
/* Save the argument index, and... */
unsigned t_wait_idx = args.length ();
unsigned num_waits = 0;
c = find_omp_clause (clauses, OMP_CLAUSE_WAIT);
- if (!tagging || c || t_async)
+ if (!tagging || c)
/* ... push a placeholder. */
args.safe_push (integer_zero_node);
- if (tagging && t_async)
- args.safe_push (t_async);
-
for (; c; c = OMP_CLAUSE_CHAIN (c))
if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_WAIT)
{
@@ -9901,13 +9913,13 @@ expand_omp_target (struct omp_region *re
num_waits++;
}
- if (!tagging || num_waits || t_async)
+ if (!tagging || num_waits)
{
tree len;
/* Now that we know the number, update the placeholder. */
if (tagging)
- len = oacc_launch_pack (GOMP_LAUNCH_ASYNC_WAIT,
+ len = oacc_launch_pack (GOMP_LAUNCH_WAIT,
NULL_TREE, num_waits);
else
len = build_int_cst (integer_type_node, num_waits);
Index: libgomp/oacc-parallel.c
===================================================================
--- libgomp/oacc-parallel.c (revision 226346)
+++ libgomp/oacc-parallel.c (working copy)
@@ -268,11 +268,20 @@ GOACC_parallel_keyed (int device, void (
}
break;
- case GOMP_LAUNCH_ASYNC_WAIT:
+ case GOMP_LAUNCH_ASYNC:
+ {
+ /* Small constant values are encoded in the operand. */
+ async = GOMP_LAUNCH_OP (tag);
+
+ if (async == GOMP_LAUNCH_OP_MAX)
+ async = va_arg (ap, unsigned);
+ break;
+ }
+
+ case GOMP_LAUNCH_WAIT:
{
unsigned num_waits = GOMP_LAUNCH_OP (tag);
- async = va_arg (ap, unsigned);
if (num_waits)
goacc_wait (async, num_waits, &ap);
break;
@@ -357,8 +366,9 @@ GOACC_parallel (int device, void (*fn) (
GOMP_LAUNCH_PACK (GOMP_LAUNCH_DIM, 0,
GOMP_DIM_MASK (GOMP_DIM_MAX) - 1),
num_gangs, num_workers, vector_length,
- GOMP_LAUNCH_PACK (GOMP_LAUNCH_ASYNC_WAIT,
- 0, num_waits),
+ GOMP_LAUNCH_PACK (GOMP_LAUNCH_ASYNC, 0,
+ GOMP_LAUNCH_OP_MAX), async,
+ GOMP_LAUNCH_PACK (GOMP_LAUNCH_WAIT, 0, num_waits),
async, waits[0], waits[1], waits[2], waits[3],
waits[4], waits[5], waits[6], waits[7], waits[8]);
}
Index: libgomp/plugin/plugin-nvptx.c
===================================================================
--- libgomp/plugin/plugin-nvptx.c (revision 226346)
+++ libgomp/plugin/plugin-nvptx.c (working copy)
@@ -1346,6 +1346,8 @@ nvptx_wait (int async)
if (!s)
GOMP_PLUGIN_fatal ("unknown async %d", async);
+ GOMP_PLUGIN_debug (0, " %s: waiting on async=%d\n", __FUNCTION__, async);
+
r = cuStreamSynchronize (s->stream);
if (r != CUDA_SUCCESS)
GOMP_PLUGIN_fatal ("cuStreamSynchronize error: %s", cuda_error (r));
Index: include/gomp-constants.h
===================================================================
--- include/gomp-constants.h (revision 226346)
+++ include/gomp-constants.h (working copy)
@@ -131,7 +131,8 @@ enum gomp_map_kind
/* Varadic launch arguments. */
#define GOMP_LAUNCH_END 0 /* End of args, no dev or op */
#define GOMP_LAUNCH_DIM 1 /* Launch dimensions, op = mask */
-#define GOMP_LAUNCH_ASYNC_WAIT 2 /* Async & Waits, op = num waits. */
+#define GOMP_LAUNCH_ASYNC 2 /* Async, op = cst val if not MAX */
+#define GOMP_LAUNCH_WAIT 3 /* Waits, op = num waits. */
#define GOMP_LAUNCH_CODE_SHIFT 28
#define GOMP_LAUNCH_DEVICE_SHIFT 16
#define GOMP_LAUNCH_OP_SHIFT 0
@@ -142,6 +143,7 @@ enum gomp_map_kind
#define GOMP_LAUNCH_CODE(X) (((X) >> GOMP_LAUNCH_CODE_SHIFT) & 0xf)
#define GOMP_LAUNCH_DEVICE(X) (((X) >> GOMP_LAUNCH_DEVICE_SHIFT) & 0xfff)
#define GOMP_LAUNCH_OP(X) (((X) >> GOMP_LAUNCH_OP_SHIFT) & 0xffff)
+#define GOMP_LAUNCH_OP_MAX 0xffff
/* Versions of libgomp and device-specific plugins. */
#define GOMP_VERSION 0