@@ -444,16 +419,6 @@ END PROGRAM
# Optimization: Device data management
-* Syntax:
-
-
`!$ACC DATA [data_clause]`
-
-
`!$ACC END DATA`
-
-* data_clause: e.g.
`CREATE` ,
`COPYIN`
-
-# Optimization: Device data management
-
```
> NVCOMPILER_ACC_TIME=1 ./p1A
@@ -505,6 +470,39 @@ Accelerator Kernel Timing data
device time(us): total=28 max=28 min=28 avg=28
```
+# Optimization: Device data management
+
+* Syntax:
+
+
`!$ACC DATA [data_clause]`
+
+
`!$ACC END DATA`
+
+* data_clause: e.g.
`CREATE` ,
`COPYIN`
+
+# Data clauses
+
+|
Clause |
Behavior |
+| --- | ------ |
+|
COPYIN |
Check if variables are already present on device; if not create space and copy data to device |
+|
COPYOUT |
Check if variables are already present on device; if not create space and copy resulting data from device |
+|
COPY |
Behaves like both COPYIN and COPYOUT |
+|
CREATE |
Check if variables are already present on device; if not create empty space |
+|
PRESENT |
Assume that variables are already present on device |
+
+
Remark: Scalars are first private by default, they rarely appear in a data clause
+
+# Update clauses
+
+Within data regions host and device memory can be updated with the
`UPDATE` clause
+
+
+
+|
Clause |
Behavior |
+| --- | ------ |
+|
UPDATE DEVICE |
Copy data from host to device |
+|
UPDATE SELF UPDATE HOST |
Copy data from device to host |
+
# Explicit data transfer