perf powerpc: Allocate and setup aux buffer queue to help co-relate with other events across CPU's

When the Dispatch Trace Log data is collected along with other events
like sched tracepoint events, it needs to be correlated and present
interleaved along with these events.

Perf events can be collected parallely across the CPUs. Hence it needs
to be ensured events/dtl entries are processed in timestamp order.

An auxtrace_queue is created for each CPU.

Data within each queue is in increasing order of timestamp. Each
auxtrace queue has a array/list of auxtrace buffers.

When processing the auxtrace buffer, the data is mmapp'ed.

All auxtrace queues is maintained in auxtrace heap.

Each queue has a queue number and a timestamp.

The queues are sorted/added to head based on the time stamp.

So always the lowest timestamp (entries to be processed first) is on top
of the heap.

The auxtrace queue needs to be allocated and heap needs to be populated
in the sorted order of timestamp.

The queue needs to be filled with data only once via
powerpc_vpadtl__update_queues() function.

powerpc_vpadtl__setup_queues() iterates through all the entries to
allocate and setup the auxtrace queue.

To add to auxtrace heap, it is required to fetch the timebase of first
entry for each of the queue.

The first entry in the queue for VPA DTL PMU has the boot timebase,
frequency details which are needed to get timestamp which is required to
correlate with other events.

The very next entry is the actual trace data that provides timestamp for
occurrence of DTL event.

Formula used to get the timestamp from dtl entry is:

((timbase from DTL entry - boot time) / frequency) * 1000000000

powerpc_vpadtl_decode() adds the boot time and frequency as part of
powerpc_vpadtl_queue structure so that it can be reused.

Each of the dtl_entry is of 48 bytes size. Sometimes it could happen
that one buffer is only partially processed (if the timestamp of
occurrence of another event is more than currently processed element in
queue, it will move on to next event).

In order to keep track of position of buffer, additional fields is added
to powerpc_vpadtl_queue structure.

Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Athira Rajeev <atrajeev@linux.ibm.com>
Tested-by: Tejas Manhas <tejas05@linux.ibm.com>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Cc: Aboorva Devarajan <aboorvad@linux.ibm.com>
Cc: Aditya Bodkhe <Aditya.Bodkhe1@ibm.com>
Cc: Hari Bathini <hbathini@linux.vnet.ibm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Shrikanth Hegde <sshegde@linux.ibm.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

0 files changed, 0 insertions, 0 deletions