Hi! On Thu, 12 Dec 2013 12:31:40 +0100, I wrote: > On Fri, 8 Nov 2013 16:40:00 +0100, Jakub Jelinek <ja...@redhat.com> wrote: > > [...], device 257 is just a temporary testing hack, [...] > > > [...], once we have at least one supported offloading target, > > hopefully we'll nuke device 257. > > Hmm, in contrast, I'd advocate to preserve that device, under a proper > ID, for two (similar) reasons: even if it's the same architecture, we'll > still want a generic non-shared-memory "offloading target" for GCC > testsuite usage. We can't assume that any of the "real hardware" > acceleration devices to be available, but will still want to test the > non-shared-memory stuff. And likewise, GCC users can use this for > testing their code for shared-memory host (fallback) execution vs. > non-shared-memory execution. So basically, just like a user can decide > to use OpenMP/libgomp, but tie the runtime down to just one thread; but > that's still different from host fallback execution. Makes sense?
Here is such a libgomp plugin plus the infrastructure for initial support
of non-shared memory host execution. Any comments?
I have not yet integrated the plugin into the libgomp build system; use
something like:
$ gcc -m64 -Wall -Wextra -shared -o libgomp-plugin-host.so.1
[...]/libgomp/plugin-host.c -fPIC -O -DDEBUG
..., and then set LIBGOMP_PLUGIN_PATH=$PWD in the environment. (Plus
OMP_DEFAULT_DEVICE=0, but that's the default.)
commit 8495aab54fb244ef2643e43eb3e91a092ff0b14e
Author: Thomas Schwinge <tho...@codesourcery.com>, James Norris
<jnor...@codesourcery.com>
Date: Wed Feb 19 16:53:14 2014 +0100
libgomp: plugin for non-shared memory host execution.
libgomp/
* plugin-host.c: New file.
* target.c (struct gomp_device_descr): Add device_alloc_func,
device_free_func, device_dev2host_func, device_host2dev_func
members.
(gomp_load_plugin_for_device): Load these.
(gomp_map_vars, gomp_unmap_tgt, gomp_unmap_vars, gomp_update): Use
these.
(resolve_device, gomp_find_available_plugins): Remove ID 257 hack.
diff --git libgomp/plugin-host.c libgomp/plugin-host.c
new file mode 100644
index 0000000..5354ebe
--- /dev/null
+++ libgomp/plugin-host.c
@@ -0,0 +1,84 @@
+/* Plugin for non-shared memory host execution.
+
+ Copyright (C) 2014 Free Software Foundation, Inc.
+
+ Contributed by Thomas Schwinge <tho...@codesourcery.com>.
+
+ This file is part of the GNU OpenMP Library (libgomp).
+
+ Libgomp is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3, or (at your option)
+ any later version.
+
+ Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ more details.
+
+ Under Section 7 of GPL version 3, you are granted additional
+ permissions described in the GCC Runtime Library Exception, version
+ 3.1, as published by the Free Software Foundation.
+
+ You should have received a copy of the GNU General Public License and
+ a copy of the GCC Runtime Library Exception along with this program;
+ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+ <http://www.gnu.org/licenses/>. */
+
+/* Simple implementation of a libgomp plugin for non-shared memory host
+ execution. */
+
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+bool
+device_available (void)
+{
+#ifdef DEBUG
+ printf ("libgomp plugin: %s:%s\n", __FILE__, __FUNCTION__);
+#endif
+
+ return true;
+}
+
+void *
+device_alloc (size_t size)
+{
+ void *ptr = malloc (size);
+
+#ifdef DEBUG
+ printf ("libgomp plugin: %s:%s (%zd): %p\n", __FILE__, __FUNCTION__, size,
ptr);
+#endif
+
+ return ptr;
+}
+
+void
+device_free (void *ptr)
+{
+#ifdef DEBUG
+ printf ("libgomp plugin: %s:%s (%p)\n", __FILE__, __FUNCTION__, ptr);
+#endif
+
+ free (ptr);
+}
+
+void *device_dev2host (void *dest, const void *src, size_t n)
+{
+#ifdef DEBUG
+ printf ("libgomp plugin: %s:%s (%p, %p, %zd)\n", __FILE__, __FUNCTION__,
dest, src, n);
+#endif
+
+ return memcpy (dest, src, n);
+}
+
+void *device_host2dev (void *dest, const void *src, size_t n)
+{
+#ifdef DEBUG
+ printf ("libgomp plugin: %s:%s (%p, %p, %zd)\n", __FILE__, __FUNCTION__,
dest, src, n);
+#endif
+
+ return memcpy (dest, src, n);
+}
diff --git libgomp/target.c libgomp/target.c
index 55d3891..48f35c4 100644
--- libgomp/target.c
+++ libgomp/target.c
@@ -122,6 +122,10 @@ struct gomp_device_descr
/* Function handlers. */
bool (*device_available_func) (void);
+ void *(*device_alloc_func) (size_t);
+ void (*device_free_func) (void *);
+ void *(*device_dev2host_func)(void *, const void *, size_t);
+ void *(*device_host2dev_func)(void *, const void *, size_t);
/* Splay tree containing information about mapped memory regions. */
struct splay_tree_s dev_splay_tree;
@@ -146,14 +150,9 @@ resolve_device (int device_id)
device_id = icv->default_device_var;
}
if (device_id < 0
- || (device_id >= gomp_get_num_devices ()
- && device_id != 257))
+ || (device_id >= gomp_get_num_devices ()))
return NULL;
- /* FIXME: Temporary hack for testing non-shared address spaces on host. */
- if (device_id == 257)
- return &devices[0];
-
return &devices[device_id];
}
@@ -233,10 +232,10 @@ gomp_map_vars (struct gomp_device_descr *devicep, size_t
mapnum,
if (not_found_cnt || is_target)
{
- /* FIXME: This would be accelerator memory allocation, not
- host, and should allocate tgt_align aligned tgt_size block
- of memory. */
- tgt->to_free = gomp_malloc (tgt_size + tgt_align - 1);
+ /* Allocate tgt_align aligned tgt_size block of memory. */
+ /* FIXME: Perhaps change interface to allocate properly aligned
+ memory. */
+ tgt->to_free = devicep->device_alloc_func (tgt_size + tgt_align - 1);
tgt->tgt_start = (uintptr_t) tgt->to_free;
tgt->tgt_start = (tgt->tgt_start + tgt_align - 1) & ~(tgt_align - 1);
tgt->tgt_end = tgt->tgt_start + tgt_size;
@@ -297,13 +296,14 @@ gomp_map_vars (struct gomp_device_descr *devicep, size_t
mapnum,
break;
case 1: /* TO */
case 3: /* TOFROM */
- /* FIXME: This is supposed to be copy from host to device
- memory. Perhaps add some smarts, like if copying
+ /* Copy from host to device memory. */
+ /* FIXME: Perhaps add some smarts, like if copying
several adjacent fields from host to target, use some
host buffer to avoid sending each var individually. */
- memcpy ((void *) (tgt->tgt_start + k->tgt_offset),
- (void *) k->host_start,
- k->host_end - k->host_start);
+ devicep->device_host2dev_func((void *) (tgt->tgt_start
+ + k->tgt_offset),
+ (void *) k->host_start,
+ k->host_end - k->host_start);
break;
case 4: /* POINTER */
cur_node.host_start
@@ -337,10 +337,12 @@ gomp_map_vars (struct gomp_device_descr *devicep, size_t
mapnum,
array section. Now subtract bias to get what we want
to initialize the pointer with. */
cur_node.tgt_offset -= sizes[i];
- /* FIXME: host to device copy, see above FIXME comment. */
- memcpy ((void *) (tgt->tgt_start + k->tgt_offset),
- (void *) &cur_node.tgt_offset,
- sizeof (void *));
+ /* Copy from host to device memory. */
+ /* FIXME: see above FIXME comment. */
+ devicep->device_host2dev_func ((void *) (tgt->tgt_start
+ + k->tgt_offset),
+ (void *)
&cur_node.tgt_offset,
+ sizeof (void *));
break;
}
array++;
@@ -353,10 +355,12 @@ gomp_map_vars (struct gomp_device_descr *devicep, size_t
mapnum,
{
cur_node.tgt_offset = tgt->list[i]->tgt->tgt_start
+ tgt->list[i]->tgt_offset;
- /* FIXME: host to device copy, see above FIXME comment. */
- memcpy ((void *) (tgt->tgt_start + i * sizeof (void *)),
- (void *) &cur_node.tgt_offset,
- sizeof (void *));
+ /* Copy from host to device memory. */
+ /* FIXME: see above FIXME comment. */
+ devicep->device_host2dev_func ((void *) (tgt->tgt_start
+ + i * sizeof (void *)),
+ (void *) &cur_node.tgt_offset,
+ sizeof (void *));
}
}
@@ -367,10 +371,9 @@ gomp_map_vars (struct gomp_device_descr *devicep, size_t
mapnum,
static void
gomp_unmap_tgt (struct target_mem_desc *tgt)
{
- /* FIXME: Deallocate on target the tgt->tgt_start .. tgt->tgt_end
- region. */
+ /* Deallocate on target the tgt->tgt_start .. tgt->tgt_end region. */
if (tgt->tgt_end)
- free (tgt->to_free);
+ tgt->device_descr->device_free_func(tgt->to_free);
free (tgt->array);
free (tgt);
@@ -396,10 +399,11 @@ gomp_unmap_vars (struct target_mem_desc *tgt)
{
splay_tree_key k = tgt->list[i];
if (k->copy_from)
- /* FIXME: device to host copy. */
- memcpy ((void *) k->host_start,
- (void *) (k->tgt->tgt_start + k->tgt_offset),
- k->host_end - k->host_start);
+ /* Copy from device to host memory. */
+ devicep->device_dev2host_func ((void *) k->host_start,
+ (void *) (k->tgt->tgt_start
+ + k->tgt_offset),
+ k->host_end - k->host_start);
splay_tree_remove (&devicep->dev_splay_tree, k);
if (k->tgt->refcount > 1)
k->tgt->refcount--;
@@ -446,17 +450,23 @@ gomp_update (struct gomp_device_descr *devicep, size_t
mapnum,
(void *) n->host_start,
(void *) n->host_end);
if ((kinds[i] & 7) == 1)
- /* FIXME: host to device copy. */
- memcpy ((void *) (n->tgt->tgt_start + n->tgt_offset
- + cur_node.host_start - n->host_start),
- (void *) cur_node.host_start,
- cur_node.host_end - cur_node.host_start);
+ /* Copy from host to device memory. */
+ devicep->device_host2dev_func ((void *) (n->tgt->tgt_start
+ + n->tgt_offset
+ + cur_node.host_start
+ - n->host_start),
+ (void *) cur_node.host_start,
+ cur_node.host_end
+ - cur_node.host_start);
else if ((kinds[i] & 7) == 2)
- /* FIXME: device to host copy. */
- memcpy ((void *) cur_node.host_start,
- (void *) (n->tgt->tgt_start + n->tgt_offset
- + cur_node.host_start - n->host_start),
- cur_node.host_end - cur_node.host_start);
+ /* Copy from device to host memory. */
+ devicep->device_dev2host_func ((void *) cur_node.host_start,
+ (void *) (n->tgt->tgt_start
+ + n->tgt_offset
+ + cur_node.host_start
+ - n->host_start),
+ cur_node.host_end
+ - cur_node.host_start);
}
else
gomp_fatal ("Trying to update [%p..%p) object that is not mapped",
@@ -608,28 +618,43 @@ static bool
gomp_load_plugin_for_device (struct gomp_device_descr *device,
const char *plugin_name)
{
- if (!device || !plugin_name)
- return false;
-
- device->plugin_handle = dlopen (plugin_name, RTLD_LAZY);
- if (!device->plugin_handle)
- return false;
+ char *err = NULL;
/* Clear any existing error. */
dlerror ();
+ device->plugin_handle = dlopen (plugin_name, RTLD_LAZY);
+ if (!device->plugin_handle)
+ {
+ err = dlerror ();
+ goto out;
+ }
+
/* Check if all required functions are available in the plugin and store
- their handlers.
- TODO: check for other routines as well. */
- device->device_available_func = dlsym (device->plugin_handle,
- "device_available");
- if (dlerror () != NULL)
+ their handlers. */
+#define DLSYM(f) \
+ do \
+ { \
+ device->f##_func = dlsym (device->plugin_handle, #f); \
+ err = dlerror ();
\
+ if (err != NULL) \
+ goto out; \
+ } \
+ while (0)
+ DLSYM (device_available);
+ DLSYM (device_alloc);
+ DLSYM (device_free);
+ DLSYM (device_dev2host);
+ DLSYM (device_host2dev);
+#undef DLSYM
+
+ out:
+ if (err != NULL)
{
+ gomp_error ("while loading %s: %s", plugin_name, err);
dlclose (device->plugin_handle);
- return false;
}
-
- return true;
+ return err == NULL;
}
/* This functions scans folder, specified in environment variable
@@ -674,7 +699,6 @@ gomp_find_available_plugins (void)
if (devices == NULL)
{
num_devices = 0;
- closedir (dir);
goto out;
}
@@ -684,26 +708,10 @@ gomp_find_available_plugins (void)
gomp_mutex_init (&devices[num_devices].dev_env_lock);
num_devices++;
}
- closedir (dir);
out:
- /* FIXME: Temporary hack for testing non-shared address spaces on host.
- We create device 257 just to check memory mapping. */
- if (num_devices == 0)
- {
- num_devices = 1;
- devices = malloc (sizeof (struct gomp_device_descr));
- if (devices == NULL)
- {
- num_devices = 0;
- return;
- }
- devices[0].plugin_handle = NULL;
- devices[0].device_available_func = NULL;
- devices[0].dev_splay_tree.root = NULL;
- gomp_mutex_init (&devices[0].dev_env_lock);
- }
- devices[0].id = 257;
+ if (dir)
+ closedir (dir);
}
/* This function initializes runtime needed for offloading.
Grüße,
Thomas
pgpEOibMs9aIU.pgp
Description: PGP signature
