tmf.core: Add tracepoint for size of request

This is useful to profile why some requests are longer than others,
as well as a sanity check.

Change-Id: I14728908cdde3aeabd753c3f4131cd45a764a456
Signed-off-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
Reviewed-on: https://git.eclipse.org/r/c/tracecompass/org.eclipse.tracecompass/+/201647
Tested-by: Trace Compass Bot <tracecompass-bot@eclipse.org>
Tested-by: Patrick Tasse <patrick.tasse@gmail.com>
Reviewed-by: Patrick Tasse <patrick.tasse@gmail.com>

tmf/org.eclipse.tracecompass.tmf.core/src/org/eclipse/tracecompass/tmf/core/model/timegraph/AbstractTimeGraphDataProvider.java

@@ -96,6 +96,12 @@ public final TmfModelResponse<TimeGraphModel> fetchRowModel(Map<String, Object>
                 // getRowModel returns null if the query was cancelled.
                 return new TmfModelResponse<>(null, ITmfResponse.Status.CANCELLED, CommonStatusMessage.TASK_CANCELLED);
             }
+            long rows = models.getRows().size();
+            long states = 0;
+            for (ITimeGraphRowModel row : models.getRows()) {
+                states += row.getStates().size();
+            }
+            scope.step("complete", "rows", rows, "states", states); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
             return new TmfModelResponse<>(models, complete ? Status.COMPLETED : Status.RUNNING,
                     complete ? CommonStatusMessage.COMPLETED : CommonStatusMessage.RUNNING);
         } catch (StateSystemDisposedException | TimeRangeException | IndexOutOfBoundsException e) {