SWDEV-422771 - Adding new env HIP_LAUNCH_BLOCKING

Change-Id: I7a38999db3670682fdcf3b82789675541f17b71a

docs/how_to_guides/debugging.md

@@ -281,6 +281,7 @@ The following is the summary of the most useful environment variables in HIP.
 | HIP_HOST_COHERENT <br><sub> Coherent memory in hipHostMalloc. </sub> |  0  |  0: memory is not coherent between host and GPU. <br> 1: memory is coherent with host. |
 | AMD_DIRECT_DISPATCH <br><sub> Enable direct kernel dispatch (Currently for Linux, under development on Windows). </sub> | 1  | 0: Disable. <br> 1: Enable. |
 | GPU_MAX_HW_QUEUES <br><sub> The maximum number of hardware queues allocated per device. </sub> | 4  | The variable controls how many independent hardware queues HIP runtime can create per process, per device. If application allocates more HIP streams than this number, then HIP runtime will reuse the same hardware queues for the new streams in round robin manner. Please note, this maximum number does not apply to either hardware queues that are created for CU masked HIP streams, or cooperative queue for HIP Cooperative Groups (there is only one single queue per device). |
+| HIP_LAUNCH_BLOCKING <br><sub> Used for serialization on kernel execution. </sub> | 0 | 0: Disable. Kernel executes normally. <br> 1: Enable. Serializes kernel enqueue, behaves the same as AMD_SERIALIZE_KERNEL. |
 
 ## General Debugging Tips
 - 'gdb --args' can be used to conveniently pass the executable and arguments to gdb.