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Re: [PATCH 2/6, OpenACC, libgomp] Async re-work, oacc-* parts


Hi Chung-Lin!

On Fri, 7 Dec 2018 22:19:14 +0800, Chung-Lin Tang <cltang@pllab.cs.nthu.edu.tw> wrote:
> On 2018/12/7 07:32 PM, Thomas Schwinge wrote:
> > Does the following make sense?
> 
> I don't quite remember why I simply ensured asyncqueue creation here at the time,
> maybe simply because it allowed simpler code at this level.

Well, I think it's just overhead we can avoid.  ;-)

> OTOH, the old logic is to GOMP_fatal upon such an unknown queue case, so maybe that's
> the right thing to do (inside lookup_goacc_asyncqueue()), instead of silently allowing it to pass.
> 
> WDYT?

I argued and posted patches (or will post if not yet done) to make this
defined, valid behavior, <https://gcc.gnu.org/PR88407> "[OpenACC]
Correctly handle unseen async-arguments".  Please speak up soon if you
disagree.

Thus, I still propose that you include the following.

Please especially review the "libgomp/oacc-parallel.c:goacc_wait" change,
and confirm no corresponding "libgomp/oacc-parallel.c:GOACC_wait" change
to be done, because that code is structured differently.

commit c96c6607b77bdbf562f35209718d8b8c5705c603
Author: Thomas Schwinge <thomas@codesourcery.com>
Date:   Fri Dec 7 12:19:56 2018 +0100

    into async re-work: don't create an asyncqueue just to then test/synchronize with it
---
 libgomp/oacc-async.c    | 12 ++++++++----
 libgomp/oacc-parallel.c |  4 +++-
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git libgomp/oacc-async.c libgomp/oacc-async.c
index 553082fe3d4a..c9b134ac3380 100644
--- libgomp/oacc-async.c
+++ libgomp/oacc-async.c
@@ -119,8 +119,11 @@ acc_async_test (int async)
   if (!thr || !thr->dev)
     gomp_fatal ("no device active");
 
-  goacc_aq aq = lookup_goacc_asyncqueue (thr, true, async);
-  return thr->dev->openacc.async.test_func (aq);
+  goacc_aq aq = lookup_goacc_asyncqueue (thr, false, async);
+  if (!aq)
+    return 1;
+  else
+    return thr->dev->openacc.async.test_func (aq);
 }
 
 int
@@ -148,8 +151,9 @@ acc_wait (int async)
 
   struct goacc_thread *thr = get_goacc_thread ();
 
-  goacc_aq aq = lookup_goacc_asyncqueue (thr, true, async);
-  thr->dev->openacc.async.synchronize_func (aq);
+  goacc_aq aq = lookup_goacc_asyncqueue (thr, false, async);
+  if (aq)
+    thr->dev->openacc.async.synchronize_func (aq);
 }
 
 /* acc_async_wait is an OpenACC 1.0 compatibility name for acc_wait.  */
diff --git libgomp/oacc-parallel.c libgomp/oacc-parallel.c
index 2815a10f0386..9519abeccc2c 100644
--- libgomp/oacc-parallel.c
+++ libgomp/oacc-parallel.c
@@ -493,7 +493,9 @@ goacc_wait (int async, int num_waits, va_list *ap)
     {
       int qid = va_arg (*ap, int);
       
-      goacc_aq aq = get_goacc_asyncqueue (qid);
+      goacc_aq aq = lookup_goacc_asyncqueue (thr, false, qid);
+      if (!aq)
+	continue;
       if (acc_dev->openacc.async.test_func (aq))
 	continue;
       if (async == acc_async_sync)


Grüße
 Thomas


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