[OpenMP][libomptarget] Enable usage of unified memory for declare target link variables
Summary: This patch enables the usage of a host variable on the device for declare target link variables when unified memory is available.
Reviewers: ABataev, caomhin, grokos
Reviewed By: grokos
Subscribers: Hahnfeld, guansong, jdoerfert, openmp-commits
Tags: #openmp
Differential Revision: https://reviews.llvm.org/D60884
git-svn-id: https://llvm.org/svn/llvm-project/openmp/trunk@362505 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/libomptarget/include/omptargetplugin.h b/libomptarget/include/omptargetplugin.h
index 2876bfb..e03416c 100644
--- a/libomptarget/include/omptargetplugin.h
+++ b/libomptarget/include/omptargetplugin.h
@@ -31,6 +31,9 @@
// having to load the library, which can be expensive.
int32_t __tgt_rtl_is_valid_binary(__tgt_device_image *Image);
+// Initialize the requires flags for the device.
+int64_t __tgt_rtl_init_requires(int64_t RequiresFlags);
+
// Initialize the specified device. In case of success return 0; otherwise
// return an error code.
int32_t __tgt_rtl_init_device(int32_t ID);
diff --git a/libomptarget/plugins/cuda/src/rtl.cpp b/libomptarget/plugins/cuda/src/rtl.cpp
index fc0c1ec..844afa1 100644
--- a/libomptarget/plugins/cuda/src/rtl.cpp
+++ b/libomptarget/plugins/cuda/src/rtl.cpp
@@ -111,6 +111,9 @@
int EnvNumTeams;
int EnvTeamLimit;
+ // OpenMP Requires Flags
+ int64_t RequiresFlags;
+
//static int EnvNumThreads;
static const int HardTeamLimit = 1<<16; // 64k
static const int HardThreadLimit = 1024;
@@ -227,6 +230,9 @@
} else {
EnvNumTeams = -1;
}
+
+ // Default state.
+ RequiresFlags = OMP_REQ_UNDEFINED;
}
~RTLDeviceInfoTy() {
@@ -264,6 +270,12 @@
int32_t __tgt_rtl_number_of_devices() { return DeviceInfo.NumberOfDevices; }
+int64_t __tgt_rtl_init_requires(int64_t RequiresFlags) {
+ DP("Init requires flags to %ld\n", RequiresFlags);
+ DeviceInfo.RequiresFlags = RequiresFlags;
+ return RequiresFlags;
+}
+
int32_t __tgt_rtl_init_device(int32_t device_id) {
CUdevice cuDevice;
@@ -436,6 +448,17 @@
DPxPTR(e - HostBegin), e->name, DPxPTR(cuptr));
entry.addr = (void *)cuptr;
+ if (DeviceInfo.RequiresFlags & OMP_REQ_UNIFIED_SHARED_MEMORY &&
+ e->flags & OMP_DECLARE_TARGET_LINK) {
+ // If unified memory is present any target link variables
+ // can access host addresses directly. There is no longer a
+ // need for device copies.
+ cuMemcpyHtoD(cuptr, e->addr, sizeof(void *));
+ DP("Copy linked variable host address (" DPxMOD ")"
+ "to device address (" DPxMOD ")\n",
+ DPxPTR(*((void**)e->addr)), DPxPTR(cuptr));
+ }
+
DeviceInfo.addOffloadEntry(device_id, entry);
continue;
diff --git a/libomptarget/plugins/exports b/libomptarget/plugins/exports
index 3f9f7d4..a14bedf 100644
--- a/libomptarget/plugins/exports
+++ b/libomptarget/plugins/exports
@@ -2,6 +2,7 @@
global:
__tgt_rtl_is_valid_binary;
__tgt_rtl_number_of_devices;
+ __tgt_rtl_init_requires;
__tgt_rtl_init_device;
__tgt_rtl_load_binary;
__tgt_rtl_data_alloc;
diff --git a/libomptarget/src/device.cpp b/libomptarget/src/device.cpp
index a946b92..5ecba57 100644
--- a/libomptarget/src/device.cpp
+++ b/libomptarget/src/device.cpp
@@ -275,6 +275,9 @@
/// Init device, should not be called directly.
void DeviceTy::init() {
+ // Make call to init_requires if it exists for this plugin.
+ if (RTL->init_requires)
+ RTL->init_requires(RTLRequiresFlags);
int32_t rc = RTL->init_device(RTLDeviceID);
if (rc == OFFLOAD_SUCCESS) {
IsInit = true;
diff --git a/libomptarget/src/rtl.cpp b/libomptarget/src/rtl.cpp
index 770ae36..4eb7ab7 100644
--- a/libomptarget/src/rtl.cpp
+++ b/libomptarget/src/rtl.cpp
@@ -107,6 +107,10 @@
dynlib_handle, "__tgt_rtl_run_target_team_region")))
continue;
+ // Optional functions
+ *((void**) &R.init_requires) = dlsym(
+ dynlib_handle, "__tgt_rtl_init_requires");
+
// No devices are supported by this RTL?
if (!(R.NumberOfDevices = R.number_of_devices())) {
DP("No devices supported in this RTL\n");
diff --git a/libomptarget/src/rtl.h b/libomptarget/src/rtl.h
index 381f23e..8148e81 100644
--- a/libomptarget/src/rtl.h
+++ b/libomptarget/src/rtl.h
@@ -36,6 +36,7 @@
int32_t);
typedef int32_t(run_team_region_ty)(int32_t, void *, void **, ptrdiff_t *,
int32_t, int32_t, int32_t, uint64_t);
+ typedef int64_t(init_requires_ty)(int64_t);
int32_t Idx; // RTL index, index is the number of devices
// of other RTLs that were registered before,
@@ -60,6 +61,7 @@
data_delete_ty *data_delete;
run_region_ty *run_region;
run_team_region_ty *run_team_region;
+ init_requires_ty *init_requires;
// Are there images associated with this RTL.
bool isUsed;
@@ -78,8 +80,8 @@
#endif
is_valid_binary(0), number_of_devices(0), init_device(0),
load_binary(0), data_alloc(0), data_submit(0), data_retrieve(0),
- data_delete(0), run_region(0), run_team_region(0), isUsed(false),
- Mtx() {}
+ data_delete(0), run_region(0), run_team_region(0),
+ init_requires(0), isUsed(false), Mtx() {}
RTLInfoTy(const RTLInfoTy &r) : Mtx() {
Idx = r.Idx;
@@ -98,6 +100,7 @@
data_delete = r.data_delete;
run_region = r.run_region;
run_team_region = r.run_team_region;
+ init_requires = r.init_requires;
isUsed = r.isUsed;
}
};
