[RFC PATCH] Coalesce host to device transfers in libgomp
Thomas Schwinge
thomas@codesourcery.com
Sun Dec 9 12:53:00 GMT 2018
Hi!
On Thu, 6 Dec 2018 18:57:31 +0100, Jakub Jelinek <jakub@redhat.com> wrote:
> On Thu, Dec 06, 2018 at 06:54:20PM +0100, Thomas Schwinge wrote:
> > On Thu, 6 Dec 2018 18:18:56 +0100, Jakub Jelinek <jakub@redhat.com> wrote:
> > > On Thu, Dec 06, 2018 at 06:01:48PM +0100, Thomas Schwinge wrote:
> > > > While reviewing Chung-Lin's
> > > > <https://gcc.gnu.org/ml/gcc-patches/2018-09/msg01428.html> "[PATCH 4/6,
> > > > OpenACC, libgomp] Async re-work, libgomp/target.c changes", I noticed the
> > > > following unrelated hunk. Is that intentional or just an oversight that
> > > > it hasn't been included in your "gomp_coalesce_buf" changes (quoted below
> > > > for reference)?
> > >
> > > I believe it is intentional, the coalescing code coalesces only stuff
> > > allocated by the current gomp_map_vars call, for the link_key case we know
> > > that is not the case, it is a copy to a file scope data variable in the PTX
> > > code.
> >
> > Hmm, I thought this would just copy an address (as opposed to data) from
> > the host to the device, so that would be fine for coalescing. But I'm
> > not familiar with that code, so it's certainly possible that I'm not
> > understanding this correctly.
>
> The actual data transfer can be coalesced, just the address is copied into
> the offloaded file scope var and so that exact transfer can't be coalesced.
Ah, I see, thanks!
> > > Perhaps we could do the change but pass NULL instead
> > > of cbufp as the last argument?
Committed to trunk in r266919:
commit 9d5a0b9dbb3aa4493f6e20b711607a25783bcec3
Author: tschwinge <tschwinge@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Sun Dec 9 12:47:23 2018 +0000
Coalesce host to device transfers in libgomp: not for link pointer
libgomp/
* target.c (gomp_map_vars): Call gomp_copy_host2dev instead of
devicep->host2dev_func.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@266919 138bc75d-0d04-0410-961f-82ee72b054a4
---
libgomp/ChangeLog | 6 ++++++
libgomp/target.c | 7 ++++---
2 files changed, 10 insertions(+), 3 deletions(-)
diff --git libgomp/ChangeLog libgomp/ChangeLog
index 7ce0cdb42e14..99417ef62cf0 100644
--- libgomp/ChangeLog
+++ libgomp/ChangeLog
@@ -1,3 +1,9 @@
+2018-12-09 Thomas Schwinge <thomas@codesourcery.com>
+ Jakub Jelinek <jakub@redhat.com>
+
+ * target.c (gomp_map_vars): Call gomp_copy_host2dev instead of
+ devicep->host2dev_func.
+
2018-12-08 Jakub Jelinek <jakub@redhat.com>
PR libgomp/87995
diff --git libgomp/target.c libgomp/target.c
index 8ebc2a370a16..a62ae2c3e4b3 100644
--- libgomp/target.c
+++ libgomp/target.c
@@ -957,9 +957,10 @@ gomp_map_vars (struct gomp_device_descr *devicep, size_t mapnum,
/* Set link pointer on target to the device address of the
mapped object. */
void *tgt_addr = (void *) (tgt->tgt_start + k->tgt_offset);
- devicep->host2dev_func (devicep->target_id,
- (void *) n->tgt_offset,
- &tgt_addr, sizeof (void *));
+ /* We intentionally do not use coalescing here, as it's not
+ data allocated by the current call to this function. */
+ gomp_copy_host2dev (devicep, (void *) n->tgt_offset,
+ &tgt_addr, sizeof (void *), NULL);
}
array++;
}
Grüße
Thomas
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