Benchmark: `--save-all-traces` argument

apps/benchmark/benchmark_app.cc

Index: apps/benchmark/benchmark_app.cc
diff --git a/apps/benchmark/benchmark_app.cc b/apps/benchmark/benchmark_app.cc
index bfdc2998797f59a7cad54bf48fbf6771038267e0..8878810c1a9a7fbb1955d79aa164bd6e0d5a003a 100644
--- a/apps/benchmark/benchmark_app.cc
+++ b/apps/benchmark/benchmark_app.cc
@@ -44,24 +44,18 @@ class BenchmarkApp : public mojo::ApplicationDelegate,
       return;
     }
 
-    // Calculate a list of trace categories we want to collect: a union of all
-    // categories targeted in measurements.
-    std::set<std::string> category_set;
-    for (const Measurement& measurement : args_.measurements) {
-      std::vector<std::string> categories;
-      base::SplitString(measurement.target_event.categories, ',', &categories);
-      category_set.insert(categories.begin(), categories.end());
+    // Don't compute the categories string if all categories should be traced

[ppi, 2015/10/29 13:33:43]

End the comment with a period.

[nelly, 2015/10/29 14:20:17]

Done.

+    std::string categories_str = "*";
+    if (!args_.trace_all_categories) {
+      categories_str = ComputeCategoriesStr();
     }
-    std::vector<std::string> unique_categories(category_set.begin(),
-                                               category_set.end());
-    std::string categories_str = JoinString(unique_categories, ',');
 
     // Connect to trace collector, which will fetch the trace events produced by
     // the app being benchmarked.
     tracing::TraceCollectorPtr trace_collector;
     app->ConnectToService("mojo:tracing", &trace_collector);
     trace_collector_client_.reset(
-        new TraceCollectorClient(this, trace_collector.Pass()));
+          new TraceCollectorClient(this, trace_collector.Pass()));

[etiennej, 2015/10/29 13:35:51]

Beware of your whitespace.

[qsr, 2015/10/29 13:40:49]

Using 'git cl format' should use clang to format your CLs and allow you to think
about something else than whitespace.

[nelly, 2015/10/29 14:20:17]

Done.

     trace_collector_client_->Start(categories_str);
 
     // Start tracing the application with 1 sec of delay.
@@ -69,7 +63,21 @@ class BenchmarkApp : public mojo::ApplicationDelegate,
         FROM_HERE,
         base::Bind(&BenchmarkApp::StartTracedApplication,
             base::Unretained(this), app),
-        base::TimeDelta::FromSeconds(1));
+        base::TimeDelta::FromMilliseconds(1000));
+  }
+
+  // Compute the string of trace categories we want to collect: a union of all

[ppi, 2015/10/29 13:33:43]

Function comments should be "third-person", ie. "Computes ...".

[nelly, 2015/10/29 14:20:17]

Done.

+  // categories targeted in measurements.
+  std::string ComputeCategoriesStr() {
+    std::set<std::string> category_set;
+    for (const Measurement& measurement : args_.measurements) {
+      std::vector<std::string> categories;
+      base::SplitString(measurement.target_event.categories, ',', &categories);
+      category_set.insert(categories.begin(), categories.end());
+    }
+    std::vector<std::string> unique_categories(category_set.begin(),
+                                               category_set.end());
+    return JoinString(unique_categories, ',');
   }
 
   void StartTracedApplication(mojo::ApplicationImpl* app) {