Update cl_arm_get_core_id specification and enums
Signed-off-by: Kevin Petit <kevin.petit@arm.com>
diff --git a/extensions/arm/cl_arm_get_core_id.txt b/extensions/arm/cl_arm_get_core_id.txt
index 4962a85..5e05b56 100644
--- a/extensions/arm/cl_arm_get_core_id.txt
+++ b/extensions/arm/cl_arm_get_core_id.txt
@@ -8,12 +8,13 @@
Contributors
- Robert Elliott
- Hui Chen
+ Robert Elliott, ARM Ltd. (robert.elliott 'at' arm.com)
+ Hui Chen, ARM Ltd. (hui.chen 'at' arm.com)
+ Kevin Petit, ARM Ltd. (kevin.petit 'at' arm.com)
Contacts
- Robert Elliott, ARM (robert.elliott 'at' ARM.com)
+ Kevin Petit, ARM Ltd. (kevin.petit 'at' arm.com)
Status
@@ -21,7 +22,7 @@
Version
- Revision: #1, April 2nd, 2013
+ Revision: #2, Feb 26th, 2018
Number
@@ -29,20 +30,25 @@
Dependencies
- Requires OpenCL version 1.0 or later.
+ Requires OpenCL version 1.2 or later.
Overview
- This extension provides a built-in function which returns the physical core
- id (OpenCL Compute Unit) that a work-group is running on. This value is
+ This extension provides a built-in function which returns a unique ID
+ for the compute unit that a work-group is running on. This value is
uniform for a work-group.
This value can be used for a core-specific cache or atomic pool where the
storage is required to be in global memory and persistent (but not ordered)
- between work-groups. This does not provide any additional ordering on top
+ between work-groups. This does not provide any additional ordering on top
of the existing guarantees between workgroups, nor does it provide any
guarantee of concurrent execution.
+ The IDs for the compute units may not be consecutive and applications must
+ make sure they allocate enough memory to accommodate all the compute units
+ present on the device. A device info query allows the application to
+ know the IDs associated with the compute units on a given device.
+
The extension string cl_arm_core_id is returned for devices and platforms
which support this extension.
@@ -56,20 +62,32 @@
New Procedures and Functions
+ Device Info query
+
+ CL_DEVICE_COMPUTE_UNITS_BITFIELD_ARM (return type cl_ulong) returns a
+ bitfield where each bit set represents the presence of compute unit whose
+ ID is the bit position. The highest ID for any compute unit on the device
+ is the position of the most significant bit set. The total number of
+ elements an application should allocate in an array indexed by core IDs is
+ thus given by:
+
+ ALLOC = sizeof(cl_ulong) * 8 - CLZ(CL_DEVICE_COMPUTE_UNITS_BITFIELD_ARM)
+
Built-in Function
uint arm_get_core_id( void )
Description
- Returns a uint that represents the physical core id, in the range 0 to
- CL_DEVICE_MAX_COMPUTE_UNITS-1
+ Returns the compute unit id as a uint, in the range [0;ALLOC-1]
Example
- // Host code, size pool based on required_instance_size * number_of_compute_units
+ // Host code, size pool based on required_instance_size * ALLOC
size_t required_instance_size = 1024;
- cl_mem core_pool = clCreateBuffer( ctx, CL_MEM_READ_WRITE, required_instance_size * CL_DEVICE_MAX_COMPUTE_UNITS, NULL, NULL );
+ cl_mem core_pool = clCreateBuffer(context,
+ CL_MEM_READ_WRITE,
+ required_instance_size * ALLOC, NULL, NULL);
// Device/Kernel code, select memory instance
kernel void test( global char *per_core_pool, global char *input, uint required_instance_size )
@@ -83,4 +101,10 @@
OpenCL kernel code Now has access to:
#pragma OPENCL EXTENSION cl_arm_core_id : enable
- The define cl_arm_core_id is also present
+ The preprocessor macro cl_arm_core_id is also present
+
+Revision History
+
+ Revision: #1, Apr 2nd, 2013 - Initial revision
+ Revision: #2, Feb 26th, 2018 - Added support for sparsely allocated compute
+ unit IDs.
diff --git a/xml/cl.xml b/xml/cl.xml
index 75394cb..d06a58b 100644
--- a/xml/cl.xml
+++ b/xml/cl.xml
@@ -1035,7 +1035,7 @@
<enum value="0x40BC" name="CL_COMMAND_SVM_MEMFILL_ARM"/>
<enum value="0x40BD" name="CL_COMMAND_SVM_MAP_ARM"/>
<enum value="0x40BE" name="CL_COMMAND_SVM_UNMAP_ARM"/>
- <unused start="0x40BF"/>
+ <enum value="0x40BF" name="CL_DEVICE_COMPUTE_UNITS_BITFIELD_ARM"/>
</enums>
<enums namespace="CL" start="0x40C0" end="0x40CF" vendor="Qualcomm" comment="Per Bug 10726">
