A trace buffer is used to efficiently store synchronous event records
so that they can be processed later, possibly in a different thread,
when the buffer is flushed. This helps reduce the latency added by
tracing API calls.
The API does not need to use trace buffers as synchronous events are
directly reported to the client with callbacks, and asynchronous events
(activities) are saved in memory pools.
The implentation of HSA asynchronous memory copy activities was using
a trace buffer shared with the tracer tool to write the records to a
file (async_copy_trace.txt), instead of using a memory pool and
reporting the activity to the client.
Removed the asynchronous memory copies trace buffer, and updated
hsa_async_copy_handler to use the pool specified when the activity
was enabled.
Updated the tracer tool to read HSA_OP_ID_COPY records out of the
default memory pool and write them to async_copy_trace.txt.
Move trace_buffer.h to test/tool as tracer_tool.cpp is now the only
file using it.
Change-Id: Ida95aba2eaf3c3f2a979ed6c2b060374017b7424
Laurent Morichetti
61f35b0204