Create a trace import duration metric

tracing/tracing/metrics/tracing_metric.html

Index: tracing/tracing/metrics/tracing_metric.html
diff --git a/tracing/tracing/metrics/tracing_metric.html b/tracing/tracing/metrics/tracing_metric.html
index fa81c2f789f723de8626ef4a84a98e93813f8e25..4f8c2223046e781e69f73b8165f010396811c392 100644
--- a/tracing/tracing/metrics/tracing_metric.html
+++ b/tracing/tracing/metrics/tracing_metric.html
@@ -92,11 +92,16 @@ tr.exportTo('tr.metrics', function() {
     histograms.addHistogram(traceBytesPerDumpValue);
   }
 
+  // TODO(charliea): The metrics in this file should be renamed to have names
+  // more consistent with those in the rest of the codebase
+  // (e.g. 'trace_size_growth_rate' with a unit of bytes/second, not 'Max event

[benjhayden, 2017/02/17 16:48:55]

This comment is fine as is, but I wanted to make a note that it might require
more discussion before fixing:
All of the current units are simple: ms, B, W, J.
Do we really need to define complex units like bytes/second?
Should it be bytes/ms for consistency? Or should ms be changed to seconds?
How would conversion work for complex units? Would we need to be able to convert
to e.g. TB/year?
Do we need to define a calculus of complex Units to express B/s, J/s?

Again, no need to change the comment, just thoughts to keep in mind.

[charliea (OOO until 10-5), 2017/02/17 20:26:04]

Hmmm, yea, you're completely right. I hadn't really given much thought about how
this would complicate our existing unit system. And what if the numerator is
something that we don't have a unit for, like "garbage collections" if we're
measuring GCs/second? It seems like keeping this as "bytes" and just renaming
the metric to something like "trace_size_growth_per_second" is a better idea.

As for the millisecond/second thing, I think there are definitely a lot of ideas
that are more easily expressed in seconds than milliseconds (e.g. power is
energy per second, and bytes/second for trace size growth makes more second to
me than bytes/millisecond). We can sort that out when we implement it, though.

+  // size in bytes per second').
+  // https://github.com/catapult-project/catapult/issues/3233
   function tracingMetric(histograms, model) {
-    if (!model.stats.hasEventSizesinBytes) {
-      throw new Error('Model stats does not have event size information. ' +
-                      'Please enable ImportOptions.trackDetailedModelStats.');
-    }
+    addTimeDurationHistogram(

[charliea (OOO until 10-5), 2017/02/17 16:16:58]

As described above, I erred on the side of consistency with the rest of the
codebase with the metric name rather than consistency with the other metrics in
this file, which should almost certainly be renamed.

+        'trace_import_duration', model.stats.traceImportDurationMs, histograms);
+
+    if (!model.stats.hasEventSizesinBytes) return;

[charliea (OOO until 10-5), 2017/02/17 16:16:58]

This brings the metric more in line with other metrics, which just don't add
their histograms if the required data isn't available. Without this change, we
could never actually turn on the tracing metric for a benchmark because
hasEventSizesInBytes can only be turned on for interactive traces (I think).

 
     var eventStats = model.stats.allTraceEventStatsInTimeIntervals;
     eventStats.sort(function(a, b) {