Don't use libgomp 'cbuf' buffering with OpenACC 'async'
The host data might not be computed yet (by an earlier asynchronous compute region, for example. libgomp/ * target.c (gomp_coalesce_buf_add): Update comment. (gomp_copy_host2dev, gomp_map_vars_internal): Don't expect to see 'aq && cbuf'. (gomp_map_vars_internal): Only 'if (!aq)', do 'gomp_coalesce_buf_add'. * testsuite/libgomp.oacc-c-c++-common/async-data-1-2.c: Remove XFAIL. Co-Authored-By: Julian Brown <julian@codesourcery.com>
This commit is contained in:
Thomas Schwinge
parent
9c41f5b9cd
commit
d88a695158
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@ -275,7 +275,14 @@ struct gomp_coalesce_buf
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host to device (e.g. map(alloc:), map(from:) etc.). */
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#define MAX_COALESCE_BUF_GAP (4 * 1024)
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/* Add region with device tgt_start relative offset and length to CBUF. */
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/* Add region with device tgt_start relative offset and length to CBUF.
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This must not be used for asynchronous copies, because the host data might
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not be computed yet (by an earlier asynchronous compute region, for
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example).
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TODO ... but we could allow CBUF usage for EPHEMERAL data? (Open question:
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is it more performant to use libgomp CBUF buffering or individual device
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asyncronous copying?) */
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static inline void
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gomp_coalesce_buf_add (struct gomp_coalesce_buf *cbuf, size_t start, size_t len)
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@ -339,6 +346,30 @@ gomp_copy_host2dev (struct gomp_device_descr *devicep,
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void *d, const void *h, size_t sz,
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bool ephemeral, struct gomp_coalesce_buf *cbuf)
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{
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if (__builtin_expect (aq != NULL, 0))
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{
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/* See 'gomp_coalesce_buf_add'. */
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assert (!cbuf);
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void *h_buf = (void *) h;
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if (ephemeral)
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{
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/* We're queueing up an asynchronous copy from data that may
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disappear before the transfer takes place (i.e. because it is a
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stack local in a function that is no longer executing). Make a
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copy of the data into a temporary buffer in those cases. */
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h_buf = gomp_malloc (sz);
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memcpy (h_buf, h, sz);
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}
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goacc_device_copy_async (devicep, devicep->openacc.async.host2dev_func,
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"dev", d, "host", h_buf, h, sz, aq);
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if (ephemeral)
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/* Free temporary buffer once the transfer has completed. */
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devicep->openacc.async.queue_callback_func (aq, free, h_buf);
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return;
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}
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if (cbuf)
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{
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uintptr_t doff = (uintptr_t) d - cbuf->tgt->tgt_start;
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@ -364,26 +395,8 @@ gomp_copy_host2dev (struct gomp_device_descr *devicep,
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}
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}
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}
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if (__builtin_expect (aq != NULL, 0))
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{
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void *h_buf = (void *) h;
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if (ephemeral)
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{
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/* We're queueing up an asynchronous copy from data that may
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disappear before the transfer takes place (i.e. because it is a
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stack local in a function that is no longer executing). Make a
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copy of the data into a temporary buffer in those cases. */
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h_buf = gomp_malloc (sz);
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memcpy (h_buf, h, sz);
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}
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goacc_device_copy_async (devicep, devicep->openacc.async.host2dev_func,
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"dev", d, "host", h_buf, h, sz, aq);
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if (ephemeral)
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/* Free temporary buffer once the transfer has completed. */
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devicep->openacc.async.queue_callback_func (aq, free, h_buf);
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}
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else
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gomp_device_copy (devicep, devicep->host2dev_func, "dev", d, "host", h, sz);
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gomp_device_copy (devicep, devicep->host2dev_func, "dev", d, "host", h, sz);
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}
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attribute_hidden void
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@ -959,8 +972,9 @@ gomp_map_vars_internal (struct gomp_device_descr *devicep,
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for (i = first; i <= last; i++)
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{
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tgt->list[i].key = NULL;
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if (gomp_to_device_kind_p (get_kind (short_mapkind, kinds, i)
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& typemask))
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if (!aq
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&& gomp_to_device_kind_p (get_kind (short_mapkind, kinds, i)
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& typemask))
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gomp_coalesce_buf_add (&cbuf,
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tgt_size - cur_node.host_end
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+ (uintptr_t) hostaddrs[i],
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@ -1001,8 +1015,9 @@ gomp_map_vars_internal (struct gomp_device_descr *devicep,
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if (tgt_align < align)
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tgt_align = align;
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tgt_size = (tgt_size + align - 1) & ~(align - 1);
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gomp_coalesce_buf_add (&cbuf, tgt_size,
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cur_node.host_end - cur_node.host_start);
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if (!aq)
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gomp_coalesce_buf_add (&cbuf, tgt_size,
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cur_node.host_end - cur_node.host_start);
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tgt_size += cur_node.host_end - cur_node.host_start;
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has_firstprivate = true;
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continue;
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@ -1095,7 +1110,8 @@ gomp_map_vars_internal (struct gomp_device_descr *devicep,
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if (tgt_align < align)
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tgt_align = align;
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tgt_size = (tgt_size + align - 1) & ~(align - 1);
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if (gomp_to_device_kind_p (kind & typemask))
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if (!aq
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&& gomp_to_device_kind_p (kind & typemask))
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gomp_coalesce_buf_add (&cbuf, tgt_size,
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cur_node.host_end - cur_node.host_start);
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tgt_size += cur_node.host_end - cur_node.host_start;
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@ -1596,6 +1612,9 @@ gomp_map_vars_internal (struct gomp_device_descr *devicep,
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if (cbufp)
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{
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/* See 'gomp_coalesce_buf_add'. */
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assert (!aq);
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long c = 0;
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for (c = 0; c < cbuf.chunk_cnt; ++c)
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gomp_copy_host2dev (devicep, aq,
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@ -1,10 +1,9 @@
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/* Verify back to back 'async' operations, two data mappings.
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Due to two data mappings, this is using the libgomp 'cbuf' buffering.
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Make sure that despite two data mappings, this isn't using the libgomp
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'cbuf' buffering.
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*/
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/* { dg-xfail-run-if "TODO" { openacc_radeon_accel_selected } } */
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#include <stdlib.h>
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