When printing top stats, include count

Instead of just accumulating the time for each instance under a
statistics call, also keep track of how many times it was called:

  *kati*: func shell time: 0.822685 / 148 (114 unique)
  *kati*:   0.019 / 3 cd foo; find -L ../src -name "*.java" -and -not -name ".*"
  ...

Due to line length concerns, I didn't put the average (elapsed/count), but
that's fairly easy to calculate by hand. I also added the '(X unique)'
to understand how unique the calls are.

If it becomes useful in the future, this would be extensible to support
bucketed count -- allowing generation of histograms. I don't expect enough
variation to need that with any stats uses today.

Update to c++17 (the default in Android) to support decomposition
declarations.

Change-Id: I357fb4fdc155dc0be5103f4f3a268f2cdaa4201a

3 files changed, 35 insertions, 13 deletions

diff --git a/Makefile.ckati b/Makefile.ckati
index e4067bb..6337590 100644
--- a/Makefile.ckati
+++ b/Makefile.ckati
@@ -82,17 +82,17 @@ endif
 # Rule to build ckati into KATI_BIN_PATH
 $(KATI_BIN_PATH)/ckati: $(KATI_CXX_OBJS) $(KATI_CXX_GENERATED_OBJS)
 	@mkdir -p $(dir $@)
-	$(KATI_LD) -std=c++11 $(KATI_CXXFLAGS) -o $@ $^ $(KATI_LIBS)
+	$(KATI_LD) -std=c++17 $(KATI_CXXFLAGS) -o $@ $^ $(KATI_LIBS)
 
 # Rule to build normal source files into object files in KATI_INTERMEDIATES_PATH
 $(KATI_CXX_OBJS) $(KATI_CXX_TEST_OBJS): $(KATI_INTERMEDIATES_PATH)/%.o: $(KATI_SRC_PATH)/%.cc
 	@mkdir -p $(dir $@)
-	$(KATI_CXX) -c -std=c++11 $(KATI_CXXFLAGS) -o $@ $<
+	$(KATI_CXX) -c -std=c++17 $(KATI_CXXFLAGS) -o $@ $<
 
 # Rule to build generated source files into object files in KATI_INTERMEDIATES_PATH
 $(KATI_CXX_GENERATED_OBJS): $(KATI_INTERMEDIATES_PATH)/%.o: $(KATI_INTERMEDIATES_PATH)/%.cc
 	@mkdir -p $(dir $@)
-	$(KATI_CXX) -c -std=c++11 $(KATI_CXXFLAGS) -o $@ $<
+	$(KATI_CXX) -c -std=c++17 $(KATI_CXXFLAGS) -o $@ $<
 
 ckati_tests: $(KATI_CXX_TEST_EXES)
 
diff --git a/stats.cc b/stats.cc
index c6687c4..eba36a1 100644
--- a/stats.cc
+++ b/stats.cc
@@ -42,20 +42,35 @@ Stats::Stats(const char* name) : name_(name), elapsed_(0), cnt_(0) {
 void Stats::DumpTop() const {
   unique_lock<mutex> lock(mu_);
   if (detailed_.size() > 0) {
-    vector<pair<string, double>> v(detailed_.begin(), detailed_.end());
-    sort(
-        v.begin(), v.end(),
-        [](const pair<string, double> a, const pair<string, double> b) -> bool {
-          return a.second > b.second;
-        });
-    for (unsigned int i = 0; i < 10 && i < v.size(); i++) {
-      LOG_STAT(" %5.3f %s", v[i].first.c_str(), v[i].second);
+    vector<pair<string, StatsDetails>> details(detailed_.begin(),
+                                               detailed_.end());
+    sort(details.begin(), details.end(),
+         [](const pair<string, StatsDetails> a,
+            const pair<string, StatsDetails> b) -> bool {
+           return a.second.elapsed_ > b.second.elapsed_;
+         });
+
+    // Only print the top 10
+    details.resize(min(details.size(), 10LU));
+
+    int max_cnt_len = 1;
+    for (auto& [name, detail] : details) {
+      max_cnt_len =
+          max(max_cnt_len, static_cast<int>(to_string(detail.cnt_).length()));
+    }
+
+    for (auto& [name, detail] : details) {
+      LOG_STAT(" %6.3f / %*d %s", detail.elapsed_, max_cnt_len, detail.cnt_,
+               name.c_str());
     }
   }
 }
 
 string Stats::String() const {
   unique_lock<mutex> lock(mu_);
+  if (!detailed_.empty())
+    return StringPrintf("%s: %f / %d (%d unique)", name_, elapsed_, cnt_,
+                        detailed_.size());
   return StringPrintf("%s: %f / %d", name_, elapsed_, cnt_);
 }
 
@@ -71,7 +86,9 @@ double Stats::End(double start, const char* msg) {
   unique_lock<mutex> lock(mu_);
   elapsed_ += e;
   if (msg != 0) {
-    detailed_[string(msg)] += e;
+    StatsDetails& details = detailed_[string(msg)];
+    details.elapsed_ += e;
+    details.cnt_++;
   }
   return e;
 }
diff --git a/stats.h b/stats.h
index 6480d5f..d9fd675 100644
--- a/stats.h
+++ b/stats.h
@@ -21,6 +21,11 @@
 
 using namespace std;
 
+struct StatsDetails {
+  int cnt_ = 0;
+  double elapsed_ = 0;
+};
+
 class Stats {
  public:
   explicit Stats(const char* name);
@@ -38,7 +43,7 @@ class Stats {
   double elapsed_;
   int cnt_;
   mutable mutex mu_;
-  unordered_map<string, double> detailed_;
+  unordered_map<string, StatsDetails> detailed_;
 };
 
 class ScopedStatsRecorder {