Introduce "family index" field into JSON output (#1164)

It may be useful for those wishing to further post-process JSON results,
but it is mainly geared towards better support for run interleaving,
where results from the same family may not be close-by in the JSON.

While we won't be able to do much about that for outputs,
the tools can and perhaps should reorder the results to that
at least in their output they are in proper order, not run order.

Note that this only counts the families that were filtered-in,
so if e.g. there were three families, and we filtered-out
the second one, the two families (which were first and third)
will have family indexes 0 and 1.

17 files changed, 159 insertions, 36 deletions

diff --git a/include/benchmark/benchmark.h b/include/benchmark/benchmark.h
index 58d9237..693c2b8 100644
--- a/include/benchmark/benchmark.h
+++ b/include/benchmark/benchmark.h
@@ -1418,6 +1418,7 @@ class BenchmarkReporter {
 
     std::string benchmark_name() const;
     BenchmarkName run_name;
+    int64_t family_index;
     RunType run_type;
     std::string aggregate_name;
     std::string report_label;  // Empty if not set by benchmark.
diff --git a/src/benchmark_api_internal.cc b/src/benchmark_api_internal.cc
index 553ff44..c481317 100644
--- a/src/benchmark_api_internal.cc
+++ b/src/benchmark_api_internal.cc
@@ -7,10 +7,11 @@
 namespace benchmark {
 namespace internal {
 
-BenchmarkInstance::BenchmarkInstance(Benchmark* benchmark,
+BenchmarkInstance::BenchmarkInstance(Benchmark* benchmark, int family_idx,
                                      const std::vector<int64_t>& args,
                                      int thread_count)
     : benchmark_(*benchmark),
+      family_index_(family_idx),
       aggregation_report_mode_(benchmark_.aggregation_report_mode_),
       args_(args),
       time_unit_(benchmark_.time_unit_),
diff --git a/src/benchmark_api_internal.h b/src/benchmark_api_internal.h
index b0595e5..5ee6fad 100644
--- a/src/benchmark_api_internal.h
+++ b/src/benchmark_api_internal.h
@@ -17,10 +17,11 @@ namespace internal {
 // Information kept per benchmark we may want to run
 class BenchmarkInstance {
  public:
-  BenchmarkInstance(Benchmark* benchmark, const std::vector<int64_t>& args,
-                    int threads);
+  BenchmarkInstance(Benchmark* benchmark, int family_index,
+                    const std::vector<int64_t>& args, int threads);
 
   const BenchmarkName& name() const { return name_; }
+  int family_index() const { return family_index_; }
   AggregationReportMode aggregation_report_mode() const {
     return aggregation_report_mode_;
   }
@@ -45,6 +46,7 @@ class BenchmarkInstance {
  private:
   BenchmarkName name_;
   Benchmark& benchmark_;
+  const int family_index_;
   AggregationReportMode aggregation_report_mode_;
   const std::vector<int64_t>& args_;
   TimeUnit time_unit_;
diff --git a/src/benchmark_register.cc b/src/benchmark_register.cc
index ebea2d9..bc6c668 100644
--- a/src/benchmark_register.cc
+++ b/src/benchmark_register.cc
@@ -129,8 +129,12 @@ bool BenchmarkFamilies::FindBenchmarks(
   // Special list of thread counts to use when none are specified
   const std::vector<int> one_thread = {1};
 
+  int next_family_index = 0;
+
   MutexLock l(mutex_);
   for (std::unique_ptr<Benchmark>& family : families_) {
+    int family_index = next_family_index;
+
     // Family was deleted or benchmark doesn't match
     if (!family) continue;
 
@@ -154,13 +158,18 @@ bool BenchmarkFamilies::FindBenchmarks(
 
     for (auto const& args : family->args_) {
       for (int num_threads : *thread_counts) {
-        BenchmarkInstance instance(family.get(), args, num_threads);
+        BenchmarkInstance instance(family.get(), family_index, args,
+                                   num_threads);
 
         const auto full_name = instance.name().str();
         if ((re.Match(full_name) && !isNegativeFilter) ||
             (!re.Match(full_name) && isNegativeFilter)) {
           instance.last_benchmark_instance = (&args == &family->args_.back());
           benchmarks->push_back(std::move(instance));
+
+          // Only bump the next family index once we've estabilished that
+          // at least one instance of this family will be run.
+          if (next_family_index == family_index) ++next_family_index;
         }
       }
     }
diff --git a/src/benchmark_runner.cc b/src/benchmark_runner.cc
index d4eb7d9..c71fc71 100644
--- a/src/benchmark_runner.cc
+++ b/src/benchmark_runner.cc
@@ -72,6 +72,7 @@ BenchmarkReporter::Run CreateRunReport(
   BenchmarkReporter::Run report;
 
   report.run_name = b.name();
+  report.family_index = b.family_index();
   report.error_occurred = results.has_error_;
   report.error_message = results.error_message_;
   report.report_label = results.report_label_;
diff --git a/src/complexity.cc b/src/complexity.cc
index aeed67f..22f4263 100644
--- a/src/complexity.cc
+++ b/src/complexity.cc
@@ -193,6 +193,7 @@ std::vector<BenchmarkReporter::Run> ComputeBigO(
   // Get the data from the accumulator to BenchmarkReporter::Run's.
   Run big_o;
   big_o.run_name = run_name;
+  big_o.family_index = reports[0].family_index;
   big_o.run_type = BenchmarkReporter::Run::RT_Aggregate;
   big_o.repetitions = reports[0].repetitions;
   big_o.repetition_index = Run::no_repetition_index;
@@ -215,6 +216,7 @@ std::vector<BenchmarkReporter::Run> ComputeBigO(
   // Only add label to mean/stddev if it is same for all runs
   Run rms;
   rms.run_name = run_name;
+  rms.family_index = reports[0].family_index;
   rms.run_type = BenchmarkReporter::Run::RT_Aggregate;
   rms.aggregate_name = "RMS";
   rms.report_label = big_o.report_label;
diff --git a/src/json_reporter.cc b/src/json_reporter.cc
index effa6bd..5a7d843 100644
--- a/src/json_reporter.cc
+++ b/src/json_reporter.cc
@@ -207,6 +207,7 @@ void JSONReporter::PrintRunData(Run const& run) {
   std::string indent(6, ' ');
   std::ostream& out = GetOutputStream();
   out << indent << FormatKV("name", run.benchmark_name()) << ",\n";
+  out << indent << FormatKV("family_index", run.family_index) << ",\n";
   out << indent << FormatKV("run_name", run.run_name.str()) << ",\n";
   out << indent << FormatKV("run_type", [&run]() -> const char* {
     switch (run.run_type) {
diff --git a/src/statistics.cc b/src/statistics.cc
index bd5a3d6..c9235e0 100644
--- a/src/statistics.cc
+++ b/src/statistics.cc
@@ -148,6 +148,7 @@ std::vector<BenchmarkReporter::Run> ComputeStats(
     // Get the data from the accumulator to BenchmarkReporter::Run's.
     Run data;
     data.run_name = reports[0].run_name;
+    data.family_index = reports[0].family_index;
     data.run_type = BenchmarkReporter::Run::RT_Aggregate;
     data.threads = reports[0].threads;
     data.repetitions = reports[0].repetitions;
diff --git a/test/BUILD b/test/BUILD
index 9bb8cb0..1f27f99 100644
--- a/test/BUILD
+++ b/test/BUILD
@@ -20,6 +20,7 @@ TEST_ARGS = ["--benchmark_min_time=0.01"]
 
 PER_SRC_TEST_ARGS = ({
     "user_counters_tabular_test.cc": ["--benchmark_counters_tabular=true"],
+    "repetitions_test.cc": [" --benchmark_repetitions=3"],
 })
 
 load("@rules_cc//cc:defs.bzl", "cc_library", "cc_test")
diff --git a/test/complexity_test.cc b/test/complexity_test.cc
index 5681fdc..34731e8 100644
--- a/test/complexity_test.cc
+++ b/test/complexity_test.cc
@@ -13,7 +13,8 @@ namespace {
   int CONCAT(dummy, __LINE__) = AddComplexityTest(__VA_ARGS__)
 
 int AddComplexityTest(std::string test_name, std::string big_o_test_name,
-                      std::string rms_test_name, std::string big_o) {
+                      std::string rms_test_name, std::string big_o,
+                      int family_index) {
   SetSubstitutions({{"%name", test_name},
                     {"%bigo_name", big_o_test_name},
                     {"%rms_name", rms_test_name},
@@ -25,25 +26,29 @@ int AddComplexityTest(std::string test_name, std::string big_o_test_name,
       {{"^%bigo_name %bigo_str %bigo_str[ ]*$"},
        {"^%bigo_name", MR_Not},  // Assert we we didn't only matched a name.
        {"^%rms_name %rms %rms[ ]*$", MR_Next}});
-  AddCases(TC_JSONOut, {{"\"name\": \"%bigo_name\",$"},
-                        {"\"run_name\": \"%name\",$", MR_Next},
-                        {"\"run_type\": \"aggregate\",$", MR_Next},
-                        {"\"repetitions\": %int,$", MR_Next},
-                        {"\"threads\": 1,$", MR_Next},
-                        {"\"aggregate_name\": \"BigO\",$", MR_Next},
-                        {"\"cpu_coefficient\": %float,$", MR_Next},
-                        {"\"real_coefficient\": %float,$", MR_Next},
-                        {"\"big_o\": \"%bigo\",$", MR_Next},
-                        {"\"time_unit\": \"ns\"$", MR_Next},
-                        {"}", MR_Next},
-                        {"\"name\": \"%rms_name\",$"},
-                        {"\"run_name\": \"%name\",$", MR_Next},
-                        {"\"run_type\": \"aggregate\",$", MR_Next},
-                        {"\"repetitions\": %int,$", MR_Next},
-                        {"\"threads\": 1,$", MR_Next},
-                        {"\"aggregate_name\": \"RMS\",$", MR_Next},
-                        {"\"rms\": %float$", MR_Next},
-                        {"}", MR_Next}});
+  AddCases(
+      TC_JSONOut,
+      {{"\"name\": \"%bigo_name\",$"},
+       {"\"family_index\": " + std::to_string(family_index) + ",$", MR_Next},
+       {"\"run_name\": \"%name\",$", MR_Next},
+       {"\"run_type\": \"aggregate\",$", MR_Next},
+       {"\"repetitions\": %int,$", MR_Next},
+       {"\"threads\": 1,$", MR_Next},
+       {"\"aggregate_name\": \"BigO\",$", MR_Next},
+       {"\"cpu_coefficient\": %float,$", MR_Next},
+       {"\"real_coefficient\": %float,$", MR_Next},
+       {"\"big_o\": \"%bigo\",$", MR_Next},
+       {"\"time_unit\": \"ns\"$", MR_Next},
+       {"}", MR_Next},
+       {"\"name\": \"%rms_name\",$"},
+       {"\"family_index\": " + std::to_string(family_index) + ",$", MR_Next},
+       {"\"run_name\": \"%name\",$", MR_Next},
+       {"\"run_type\": \"aggregate\",$", MR_Next},
+       {"\"repetitions\": %int,$", MR_Next},
+       {"\"threads\": 1,$", MR_Next},
+       {"\"aggregate_name\": \"RMS\",$", MR_Next},
+       {"\"rms\": %float$", MR_Next},
+       {"}", MR_Next}});
   AddCases(TC_CSVOut, {{"^\"%bigo_name\",,%float,%float,%bigo,,,,,$"},
                        {"^\"%bigo_name\"", MR_Not},
                        {"^\"%rms_name\",,%float,%float,,,,,,$", MR_Next}});
@@ -82,15 +87,15 @@ const char *lambda_big_o_1 = "f\\(N\\)";
 
 // Add enum tests
 ADD_COMPLEXITY_CASES(one_test_name, big_o_1_test_name, rms_o_1_test_name,
-                     enum_big_o_1);
+                     enum_big_o_1, /*family_index=*/0);
 
 // Add auto enum tests
 ADD_COMPLEXITY_CASES(one_test_name, big_o_1_test_name, rms_o_1_test_name,
-                     auto_big_o_1);
+                     auto_big_o_1, /*family_index=*/1);
 
 // Add lambda tests
 ADD_COMPLEXITY_CASES(one_test_name, big_o_1_test_name, rms_o_1_test_name,
-                     lambda_big_o_1);
+                     lambda_big_o_1, /*family_index=*/2);
 
 // ========================================================================= //
 // --------------------------- Testing BigO O(N) --------------------------- //
@@ -137,11 +142,11 @@ const char *lambda_big_o_n = "f\\(N\\)";
 
 // Add enum tests
 ADD_COMPLEXITY_CASES(n_test_name, big_o_n_test_name, rms_o_n_test_name,
-                     enum_auto_big_o_n);
+                     enum_auto_big_o_n, /*family_index=*/3);
 
 // Add lambda tests
 ADD_COMPLEXITY_CASES(n_test_name, big_o_n_test_name, rms_o_n_test_name,
-                     lambda_big_o_n);
+                     lambda_big_o_n, /*family_index=*/4);
 
 // ========================================================================= //
 // ------------------------- Testing BigO O(N*lgN) ------------------------- //
@@ -178,11 +183,13 @@ const char *lambda_big_o_n_lg_n = "f\\(N\\)";
 
 // Add enum tests
 ADD_COMPLEXITY_CASES(n_lg_n_test_name, big_o_n_lg_n_test_name,
-                     rms_o_n_lg_n_test_name, enum_auto_big_o_n_lg_n);
+                     rms_o_n_lg_n_test_name, enum_auto_big_o_n_lg_n,
+                     /*family_index=*/6);
 
 // Add lambda tests
 ADD_COMPLEXITY_CASES(n_lg_n_test_name, big_o_n_lg_n_test_name,
-                     rms_o_n_lg_n_test_name, lambda_big_o_n_lg_n);
+                     rms_o_n_lg_n_test_name, lambda_big_o_n_lg_n,
+                     /*family_index=*/7);
 
 // ========================================================================= //
 // -------- Testing formatting of Complexity with captured args ------------ //
@@ -204,7 +211,7 @@ const std::string complexity_capture_name =
     "BM_ComplexityCaptureArgs/capture_test";
 
 ADD_COMPLEXITY_CASES(complexity_capture_name, complexity_capture_name + "_BigO",
-                     complexity_capture_name + "_RMS", "N");
+                     complexity_capture_name + "_RMS", "N", /*family_index=*/9);
 
 // ========================================================================= //
 // --------------------------- TEST CASES END ------------------------------ //
diff --git a/test/filter_test.cc b/test/filter_test.cc
index fece6dc..1c19891 100644
--- a/test/filter_test.cc
+++ b/test/filter_test.cc
@@ -1,15 +1,15 @@
-#include "benchmark/benchmark.h"
-
+#include <algorithm>
 #include <cassert>
 #include <cmath>
 #include <cstdint>
 #include <cstdlib>
-
 #include <iostream>
 #include <limits>
 #include <sstream>
 #include <string>
 
+#include "benchmark/benchmark.h"
+
 namespace {
 
 class TestReporter : public benchmark::ConsoleReporter {
@@ -20,17 +20,22 @@ class TestReporter : public benchmark::ConsoleReporter {
 
   virtual void ReportRuns(const std::vector<Run>& report) BENCHMARK_OVERRIDE {
     ++count_;
+    max_family_index_ =
+        std::max<size_t>(max_family_index_, report[0].family_index);
     ConsoleReporter::ReportRuns(report);
   };
 
-  TestReporter() : count_(0) {}
+  TestReporter() : count_(0), max_family_index_(0) {}
 
   virtual ~TestReporter() {}
 
   size_t GetCount() const { return count_; }
 
+  size_t GetMaxFamilyIndex() const { return max_family_index_; }
+
  private:
   mutable size_t count_;
+  mutable size_t max_family_index_;
 };
 
 }  // end namespace
@@ -98,6 +103,15 @@ int main(int argc, char **argv) {
                 << std::endl;
       return -1;
     }
+
+    const size_t max_family_index = test_reporter.GetMaxFamilyIndex();
+    const size_t num_families = reports_count == 0 ? 0 : 1 + max_family_index;
+    if (num_families != expected_reports) {
+      std::cerr << "ERROR: Expected " << expected_reports
+                << " test families to be run but num_families = "
+                << num_families << std::endl;
+      return -1;
+    }
   }
 
   return 0;
diff --git a/test/memory_manager_test.cc b/test/memory_manager_test.cc
index 4e0e649..0c31274 100644
--- a/test/memory_manager_test.cc
+++ b/test/memory_manager_test.cc
@@ -21,6 +21,7 @@ BENCHMARK(BM_empty);
 
 ADD_CASES(TC_ConsoleOut, {{"^BM_empty %console_report$"}});
 ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_empty\",$"},
+                       {"\"family_index\": 0,$", MR_Next},
                        {"\"run_name\": \"BM_empty\",$", MR_Next},
                        {"\"run_type\": \"iteration\",$", MR_Next},
                        {"\"repetitions\": 1,$", MR_Next},
diff --git a/test/repetitions_test.cc b/test/repetitions_test.cc
index 5980c99..a5ab875 100644
--- a/test/repetitions_test.cc
+++ b/test/repetitions_test.cc
@@ -24,6 +24,7 @@ ADD_CASES(TC_ConsoleOut,
           {{"^BM_ExplicitRepetitions/repeats:2_stddev %console_report$"}});
 ADD_CASES(TC_JSONOut,
           {{"\"name\": \"BM_ExplicitRepetitions/repeats:2\",$"},
+           {"\"family_index\": 0,$", MR_Next},
            {"\"run_name\": \"BM_ExplicitRepetitions/repeats:2\",$", MR_Next},
            {"\"run_type\": \"iteration\",$", MR_Next},
            {"\"repetitions\": 2,$", MR_Next},
@@ -36,6 +37,7 @@ ADD_CASES(TC_JSONOut,
            {"}", MR_Next}});
 ADD_CASES(TC_JSONOut,
           {{"\"name\": \"BM_ExplicitRepetitions/repeats:2\",$"},
+           {"\"family_index\": 0,$", MR_Next},
            {"\"run_name\": \"BM_ExplicitRepetitions/repeats:2\",$", MR_Next},
            {"\"run_type\": \"iteration\",$", MR_Next},
            {"\"repetitions\": 2,$", MR_Next},
@@ -48,6 +50,7 @@ ADD_CASES(TC_JSONOut,
            {"}", MR_Next}});
 ADD_CASES(TC_JSONOut,
           {{"\"name\": \"BM_ExplicitRepetitions/repeats:2_mean\",$"},
+           {"\"family_index\": 0,$", MR_Next},
            {"\"run_name\": \"BM_ExplicitRepetitions/repeats:2\",$", MR_Next},
            {"\"run_type\": \"aggregate\",$", MR_Next},
            {"\"repetitions\": 2,$", MR_Next},
@@ -60,6 +63,7 @@ ADD_CASES(TC_JSONOut,
            {"}", MR_Next}});
 ADD_CASES(TC_JSONOut,
           {{"\"name\": \"BM_ExplicitRepetitions/repeats:2_median\",$"},
+           {"\"family_index\": 0,$", MR_Next},
            {"\"run_name\": \"BM_ExplicitRepetitions/repeats:2\",$", MR_Next},
            {"\"run_type\": \"aggregate\",$", MR_Next},
            {"\"repetitions\": 2,$", MR_Next},
@@ -72,6 +76,7 @@ ADD_CASES(TC_JSONOut,
            {"}", MR_Next}});
 ADD_CASES(TC_JSONOut,
           {{"\"name\": \"BM_ExplicitRepetitions/repeats:2_stddev\",$"},
+           {"\"family_index\": 0,$", MR_Next},
            {"\"run_name\": \"BM_ExplicitRepetitions/repeats:2\",$", MR_Next},
            {"\"run_type\": \"aggregate\",$", MR_Next},
            {"\"repetitions\": 2,$", MR_Next},
@@ -108,6 +113,7 @@ ADD_CASES(TC_ConsoleOut, {{"^BM_ImplicitRepetitions_mean %console_report$"}});
 ADD_CASES(TC_ConsoleOut, {{"^BM_ImplicitRepetitions_median %console_report$"}});
 ADD_CASES(TC_ConsoleOut, {{"^BM_ImplicitRepetitions_stddev %console_report$"}});
 ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_ImplicitRepetitions\",$"},
+                       {"\"family_index\": 1,$", MR_Next},
                        {"\"run_name\": \"BM_ImplicitRepetitions\",$", MR_Next},
                        {"\"run_type\": \"iteration\",$", MR_Next},
                        {"\"repetitions\": 3,$", MR_Next},
@@ -119,6 +125,7 @@ ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_ImplicitRepetitions\",$"},
                        {"\"time_unit\": \"ns\"$", MR_Next},
                        {"}", MR_Next}});
 ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_ImplicitRepetitions\",$"},
+                       {"\"family_index\": 1,$", MR_Next},
                        {"\"run_name\": \"BM_ImplicitRepetitions\",$", MR_Next},
                        {"\"run_type\": \"iteration\",$", MR_Next},
                        {"\"repetitions\": 3,$", MR_Next},
@@ -130,6 +137,7 @@ ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_ImplicitRepetitions\",$"},
                        {"\"time_unit\": \"ns\"$", MR_Next},
                        {"}", MR_Next}});
 ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_ImplicitRepetitions\",$"},
+                       {"\"family_index\": 1,$", MR_Next},
                        {"\"run_name\": \"BM_ImplicitRepetitions\",$", MR_Next},
                        {"\"run_type\": \"iteration\",$", MR_Next},
                        {"\"repetitions\": 3,$", MR_Next},
@@ -141,6 +149,7 @@ ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_ImplicitRepetitions\",$"},
                        {"\"time_unit\": \"ns\"$", MR_Next},
                        {"}", MR_Next}});
 ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_ImplicitRepetitions_mean\",$"},
+                       {"\"family_index\": 1,$", MR_Next},
                        {"\"run_name\": \"BM_ImplicitRepetitions\",$", MR_Next},
                        {"\"run_type\": \"aggregate\",$", MR_Next},
                        {"\"repetitions\": 3,$", MR_Next},
@@ -152,6 +161,7 @@ ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_ImplicitRepetitions_mean\",$"},
                        {"\"time_unit\": \"ns\"$", MR_Next},
                        {"}", MR_Next}});
 ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_ImplicitRepetitions_median\",$"},
+                       {"\"family_index\": 1,$", MR_Next},
                        {"\"run_name\": \"BM_ImplicitRepetitions\",$", MR_Next},
                        {"\"run_type\": \"aggregate\",$", MR_Next},
                        {"\"repetitions\": 3,$", MR_Next},
@@ -163,6 +173,7 @@ ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_ImplicitRepetitions_median\",$"},
                        {"\"time_unit\": \"ns\"$", MR_Next},
                        {"}", MR_Next}});
 ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_ImplicitRepetitions_stddev\",$"},
+                       {"\"family_index\": 1,$", MR_Next},
                        {"\"run_name\": \"BM_ImplicitRepetitions\",$", MR_Next},
                        {"\"run_type\": \"aggregate\",$", MR_Next},
                        {"\"repetitions\": 3,$", MR_Next},
diff --git a/test/reporter_output_test.cc b/test/reporter_output_test.cc
index 31bedfa..91c6f49 100644
--- a/test/reporter_output_test.cc
+++ b/test/reporter_output_test.cc
@@ -71,6 +71,7 @@ BENCHMARK(BM_basic);
 
 ADD_CASES(TC_ConsoleOut, {{"^BM_basic %console_report$"}});
 ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_basic\",$"},
+                       {"\"family_index\": 0,$", MR_Next},
                        {"\"run_name\": \"BM_basic\",$", MR_Next},
                        {"\"run_type\": \"iteration\",$", MR_Next},
                        {"\"repetitions\": 1,$", MR_Next},
@@ -99,6 +100,7 @@ BENCHMARK(BM_bytes_per_second);
 ADD_CASES(TC_ConsoleOut, {{"^BM_bytes_per_second %console_report "
                            "bytes_per_second=%float[kM]{0,1}/s$"}});
 ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_bytes_per_second\",$"},
+                       {"\"family_index\": 1,$", MR_Next},
                        {"\"run_name\": \"BM_bytes_per_second\",$", MR_Next},
                        {"\"run_type\": \"iteration\",$", MR_Next},
                        {"\"repetitions\": 1,$", MR_Next},
@@ -128,6 +130,7 @@ BENCHMARK(BM_items_per_second);
 ADD_CASES(TC_ConsoleOut, {{"^BM_items_per_second %console_report "
                            "items_per_second=%float[kM]{0,1}/s$"}});
 ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_items_per_second\",$"},
+                       {"\"family_index\": 2,$", MR_Next},
                        {"\"run_name\": \"BM_items_per_second\",$", MR_Next},
                        {"\"run_type\": \"iteration\",$", MR_Next},
                        {"\"repetitions\": 1,$", MR_Next},
@@ -154,6 +157,7 @@ BENCHMARK(BM_label);
 
 ADD_CASES(TC_ConsoleOut, {{"^BM_label %console_report some label$"}});
 ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_label\",$"},
+                       {"\"family_index\": 3,$", MR_Next},
                        {"\"run_name\": \"BM_label\",$", MR_Next},
                        {"\"run_type\": \"iteration\",$", MR_Next},
                        {"\"repetitions\": 1,$", MR_Next},
@@ -181,6 +185,7 @@ BENCHMARK(BM_time_label_nanosecond)->Unit(benchmark::kNanosecond);
 ADD_CASES(TC_ConsoleOut, {{"^BM_time_label_nanosecond %console_report$"}});
 ADD_CASES(TC_JSONOut,
           {{"\"name\": \"BM_time_label_nanosecond\",$"},
+           {"\"family_index\": 4,$", MR_Next},
            {"\"run_name\": \"BM_time_label_nanosecond\",$", MR_Next},
            {"\"run_type\": \"iteration\",$", MR_Next},
            {"\"repetitions\": 1,$", MR_Next},
@@ -202,6 +207,7 @@ BENCHMARK(BM_time_label_microsecond)->Unit(benchmark::kMicrosecond);
 ADD_CASES(TC_ConsoleOut, {{"^BM_time_label_microsecond %console_us_report$"}});
 ADD_CASES(TC_JSONOut,
           {{"\"name\": \"BM_time_label_microsecond\",$"},
+           {"\"family_index\": 5,$", MR_Next},
            {"\"run_name\": \"BM_time_label_microsecond\",$", MR_Next},
            {"\"run_type\": \"iteration\",$", MR_Next},
            {"\"repetitions\": 1,$", MR_Next},
@@ -223,6 +229,7 @@ BENCHMARK(BM_time_label_millisecond)->Unit(benchmark::kMillisecond);
 ADD_CASES(TC_ConsoleOut, {{"^BM_time_label_millisecond %console_ms_report$"}});
 ADD_CASES(TC_JSONOut,
           {{"\"name\": \"BM_time_label_millisecond\",$"},
+           {"\"family_index\": 6,$", MR_Next},
            {"\"run_name\": \"BM_time_label_millisecond\",$", MR_Next},
            {"\"run_type\": \"iteration\",$", MR_Next},
            {"\"repetitions\": 1,$", MR_Next},
@@ -243,6 +250,7 @@ BENCHMARK(BM_time_label_second)->Unit(benchmark::kSecond);
 
 ADD_CASES(TC_ConsoleOut, {{"^BM_time_label_second %console_s_report$"}});
 ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_time_label_second\",$"},
+                       {"\"family_index\": 7,$", MR_Next},
                        {"\"run_name\": \"BM_time_label_second\",$", MR_Next},
                        {"\"run_type\": \"iteration\",$", MR_Next},
                        {"\"repetitions\": 1,$", MR_Next},
@@ -267,6 +275,7 @@ void BM_error(benchmark::State& state) {
 BENCHMARK(BM_error);
 ADD_CASES(TC_ConsoleOut, {{"^BM_error[ ]+ERROR OCCURRED: 'message'$"}});
 ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_error\",$"},
+                       {"\"family_index\": 8,$", MR_Next},
                        {"\"run_name\": \"BM_error\",$", MR_Next},
                        {"\"run_type\": \"iteration\",$", MR_Next},
                        {"\"repetitions\": 1,$", MR_Next},
@@ -289,6 +298,7 @@ void BM_no_arg_name(benchmark::State& state) {
 BENCHMARK(BM_no_arg_name)->Arg(3);
 ADD_CASES(TC_ConsoleOut, {{"^BM_no_arg_name/3 %console_report$"}});
 ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_no_arg_name/3\",$"},
+                       {"\"family_index\": 9,$", MR_Next},
                        {"\"run_name\": \"BM_no_arg_name/3\",$", MR_Next},
                        {"\"run_type\": \"iteration\",$", MR_Next},
                        {"\"repetitions\": 1,$", MR_Next},
@@ -307,6 +317,7 @@ void BM_arg_name(benchmark::State& state) {
 BENCHMARK(BM_arg_name)->ArgName("first")->Arg(3);
 ADD_CASES(TC_ConsoleOut, {{"^BM_arg_name/first:3 %console_report$"}});
 ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_arg_name/first:3\",$"},
+                       {"\"family_index\": 10,$", MR_Next},
                        {"\"run_name\": \"BM_arg_name/first:3\",$", MR_Next},
                        {"\"run_type\": \"iteration\",$", MR_Next},
                        {"\"repetitions\": 1,$", MR_Next},
@@ -327,6 +338,7 @@ ADD_CASES(TC_ConsoleOut,
           {{"^BM_arg_names/first:2/5/third:4 %console_report$"}});
 ADD_CASES(TC_JSONOut,
           {{"\"name\": \"BM_arg_names/first:2/5/third:4\",$"},
+           {"\"family_index\": 11,$", MR_Next},
            {"\"run_name\": \"BM_arg_names/first:2/5/third:4\",$", MR_Next},
            {"\"run_type\": \"iteration\",$", MR_Next},
            {"\"repetitions\": 1,$", MR_Next},
@@ -346,6 +358,7 @@ BENCHMARK(BM_name)->Name("BM_custom_name");
 
 ADD_CASES(TC_ConsoleOut, {{"^BM_custom_name %console_report$"}});
 ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_custom_name\",$"},
+                       {"\"family_index\": 12,$", MR_Next},
                        {"\"run_name\": \"BM_custom_name\",$", MR_Next},
                        {"\"run_type\": \"iteration\",$", MR_Next},
                        {"\"repetitions\": 1,$", MR_Next},
@@ -405,18 +418,21 @@ ADD_CASES(TC_ConsoleOut,
            {"^BM_Repeat/repeats:2_median %console_time_only_report [ ]*2$"},
            {"^BM_Repeat/repeats:2_stddev %console_time_only_report [ ]*2$"}});
 ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_Repeat/repeats:2\",$"},
+                       {"\"family_index\": 15,$", MR_Next},
                        {"\"run_name\": \"BM_Repeat/repeats:2\"", MR_Next},
                        {"\"run_type\": \"iteration\",$", MR_Next},
                        {"\"repetitions\": 2,$", MR_Next},
                        {"\"repetition_index\": 0,$", MR_Next},
                        {"\"threads\": 1,$", MR_Next},
                        {"\"name\": \"BM_Repeat/repeats:2\",$"},
+                       {"\"family_index\": 15,$", MR_Next},
                        {"\"run_name\": \"BM_Repeat/repeats:2\",$", MR_Next},
                        {"\"run_type\": \"iteration\",$", MR_Next},
                        {"\"repetitions\": 2,$", MR_Next},
                        {"\"repetition_index\": 1,$", MR_Next},
                        {"\"threads\": 1,$", MR_Next},
                        {"\"name\": \"BM_Repeat/repeats:2_mean\",$"},
+                       {"\"family_index\": 15,$", MR_Next},
                        {"\"run_name\": \"BM_Repeat/repeats:2\",$", MR_Next},
                        {"\"run_type\": \"aggregate\",$", MR_Next},
                        {"\"repetitions\": 2,$", MR_Next},
@@ -424,6 +440,7 @@ ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_Repeat/repeats:2\",$"},
                        {"\"aggregate_name\": \"mean\",$", MR_Next},
                        {"\"iterations\": 2,$", MR_Next},
                        {"\"name\": \"BM_Repeat/repeats:2_median\",$"},
+                       {"\"family_index\": 15,$", MR_Next},
                        {"\"run_name\": \"BM_Repeat/repeats:2\",$", MR_Next},
                        {"\"run_type\": \"aggregate\",$", MR_Next},
                        {"\"repetitions\": 2,$", MR_Next},
@@ -431,6 +448,7 @@ ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_Repeat/repeats:2\",$"},
                        {"\"aggregate_name\": \"median\",$", MR_Next},
                        {"\"iterations\": 2,$", MR_Next},
                        {"\"name\": \"BM_Repeat/repeats:2_stddev\",$"},
+                       {"\"family_index\": 15,$", MR_Next},
                        {"\"run_name\": \"BM_Repeat/repeats:2\",$", MR_Next},
                        {"\"run_type\": \"aggregate\",$", MR_Next},
                        {"\"repetitions\": 2,$", MR_Next},
@@ -452,24 +470,28 @@ ADD_CASES(TC_ConsoleOut,
            {"^BM_Repeat/repeats:3_median %console_time_only_report [ ]*3$"},
            {"^BM_Repeat/repeats:3_stddev %console_time_only_report [ ]*3$"}});
 ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_Repeat/repeats:3\",$"},
+                       {"\"family_index\": 16,$", MR_Next},
                        {"\"run_name\": \"BM_Repeat/repeats:3\",$", MR_Next},
                        {"\"run_type\": \"iteration\",$", MR_Next},
                        {"\"repetitions\": 3,$", MR_Next},
                        {"\"repetition_index\": 0,$", MR_Next},
                        {"\"threads\": 1,$", MR_Next},
                        {"\"name\": \"BM_Repeat/repeats:3\",$"},
+                       {"\"family_index\": 16,$", MR_Next},
                        {"\"run_name\": \"BM_Repeat/repeats:3\",$", MR_Next},
                        {"\"run_type\": \"iteration\",$", MR_Next},
                        {"\"repetitions\": 3,$", MR_Next},
                        {"\"repetition_index\": 1,$", MR_Next},
                        {"\"threads\": 1,$", MR_Next},
                        {"\"name\": \"BM_Repeat/repeats:3\",$"},
+                       {"\"family_index\": 16,$", MR_Next},
                        {"\"run_name\": \"BM_Repeat/repeats:3\",$", MR_Next},
                        {"\"run_type\": \"iteration\",$", MR_Next},
                        {"\"repetitions\": 3,$", MR_Next},
                        {"\"repetition_index\": 2,$", MR_Next},
                        {"\"threads\": 1,$", MR_Next},
                        {"\"name\": \"BM_Repeat/repeats:3_mean\",$"},
+                       {"\"family_index\": 16,$", MR_Next},
                        {"\"run_name\": \"BM_Repeat/repeats:3\",$", MR_Next},
                        {"\"run_type\": \"aggregate\",$", MR_Next},
                        {"\"repetitions\": 3,$", MR_Next},
@@ -477,6 +499,7 @@ ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_Repeat/repeats:3\",$"},
                        {"\"aggregate_name\": \"mean\",$", MR_Next},
                        {"\"iterations\": 3,$", MR_Next},
                        {"\"name\": \"BM_Repeat/repeats:3_median\",$"},
+                       {"\"family_index\": 16,$", MR_Next},
                        {"\"run_name\": \"BM_Repeat/repeats:3\",$", MR_Next},
                        {"\"run_type\": \"aggregate\",$", MR_Next},
                        {"\"repetitions\": 3,$", MR_Next},
@@ -484,6 +507,7 @@ ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_Repeat/repeats:3\",$"},
                        {"\"aggregate_name\": \"median\",$", MR_Next},
                        {"\"iterations\": 3,$", MR_Next},
                        {"\"name\": \"BM_Repeat/repeats:3_stddev\",$"},
+                       {"\"family_index\": 16,$", MR_Next},
                        {"\"run_name\": \"BM_Repeat/repeats:3\",$", MR_Next},
                        {"\"run_type\": \"aggregate\",$", MR_Next},
                        {"\"repetitions\": 3,$", MR_Next},
@@ -507,30 +531,35 @@ ADD_CASES(TC_ConsoleOut,
            {"^BM_Repeat/repeats:4_median %console_time_only_report [ ]*4$"},
            {"^BM_Repeat/repeats:4_stddev %console_time_only_report [ ]*4$"}});
 ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_Repeat/repeats:4\",$"},
+                       {"\"family_index\": 17,$", MR_Next},
                        {"\"run_name\": \"BM_Repeat/repeats:4\",$", MR_Next},
                        {"\"run_type\": \"iteration\",$", MR_Next},
                        {"\"repetitions\": 4,$", MR_Next},
                        {"\"repetition_index\": 0,$", MR_Next},
                        {"\"threads\": 1,$", MR_Next},
                        {"\"name\": \"BM_Repeat/repeats:4\",$"},
+                       {"\"family_index\": 17,$", MR_Next},
                        {"\"run_name\": \"BM_Repeat/repeats:4\",$", MR_Next},
                        {"\"run_type\": \"iteration\",$", MR_Next},
                        {"\"repetitions\": 4,$", MR_Next},
                        {"\"repetition_index\": 1,$", MR_Next},
                        {"\"threads\": 1,$", MR_Next},
                        {"\"name\": \"BM_Repeat/repeats:4\",$"},
+                       {"\"family_index\": 17,$", MR_Next},
                        {"\"run_name\": \"BM_Repeat/repeats:4\",$", MR_Next},
                        {"\"run_type\": \"iteration\",$", MR_Next},
                        {"\"repetitions\": 4,$", MR_Next},
                        {"\"repetition_index\": 2,$", MR_Next},
                        {"\"threads\": 1,$", MR_Next},
                        {"\"name\": \"BM_Repeat/repeats:4\",$"},
+                       {"\"family_index\": 17,$", MR_Next},
                        {"\"run_name\": \"BM_Repeat/repeats:4\",$", MR_Next},
                        {"\"run_type\": \"iteration\",$", MR_Next},
                        {"\"repetitions\": 4,$", MR_Next},
                        {"\"repetition_index\": 3,$", MR_Next},
                        {"\"threads\": 1,$", MR_Next},
                        {"\"name\": \"BM_Repeat/repeats:4_mean\",$"},
+                       {"\"family_index\": 17,$", MR_Next},
                        {"\"run_name\": \"BM_Repeat/repeats:4\",$", MR_Next},
                        {"\"run_type\": \"aggregate\",$", MR_Next},
                        {"\"repetitions\": 4,$", MR_Next},
@@ -538,6 +567,7 @@ ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_Repeat/repeats:4\",$"},
                        {"\"aggregate_name\": \"mean\",$", MR_Next},
                        {"\"iterations\": 4,$", MR_Next},
                        {"\"name\": \"BM_Repeat/repeats:4_median\",$"},
+                       {"\"family_index\": 17,$", MR_Next},
                        {"\"run_name\": \"BM_Repeat/repeats:4\",$", MR_Next},
                        {"\"run_type\": \"aggregate\",$", MR_Next},
                        {"\"repetitions\": 4,$", MR_Next},
@@ -545,6 +575,7 @@ ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_Repeat/repeats:4\",$"},
                        {"\"aggregate_name\": \"median\",$", MR_Next},
                        {"\"iterations\": 4,$", MR_Next},
                        {"\"name\": \"BM_Repeat/repeats:4_stddev\",$"},
+                       {"\"family_index\": 17,$", MR_Next},
                        {"\"run_name\": \"BM_Repeat/repeats:4\",$", MR_Next},
                        {"\"run_type\": \"aggregate\",$", MR_Next},
                        {"\"repetitions\": 4,$", MR_Next},
@@ -568,6 +599,7 @@ void BM_RepeatOnce(benchmark::State& state) {
 BENCHMARK(BM_RepeatOnce)->Repetitions(1)->ReportAggregatesOnly();
 ADD_CASES(TC_ConsoleOut, {{"^BM_RepeatOnce/repeats:1 %console_report$"}});
 ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_RepeatOnce/repeats:1\",$"},
+                       {"\"family_index\": 18,$", MR_Next},
                        {"\"run_name\": \"BM_RepeatOnce/repeats:1\",$", MR_Next},
                        {"\"run_type\": \"iteration\",$", MR_Next},
                        {"\"repetitions\": 1,$", MR_Next},
@@ -590,6 +622,7 @@ ADD_CASES(
 ADD_CASES(TC_JSONOut,
           {{".*BM_SummaryRepeat/repeats:3 ", MR_Not},
            {"\"name\": \"BM_SummaryRepeat/repeats:3_mean\",$"},
+           {"\"family_index\": 19,$", MR_Next},
            {"\"run_name\": \"BM_SummaryRepeat/repeats:3\",$", MR_Next},
            {"\"run_type\": \"aggregate\",$", MR_Next},
            {"\"repetitions\": 3,$", MR_Next},
@@ -597,6 +630,7 @@ ADD_CASES(TC_JSONOut,
            {"\"aggregate_name\": \"mean\",$", MR_Next},
            {"\"iterations\": 3,$", MR_Next},
            {"\"name\": \"BM_SummaryRepeat/repeats:3_median\",$"},
+           {"\"family_index\": 19,$", MR_Next},
            {"\"run_name\": \"BM_SummaryRepeat/repeats:3\",$", MR_Next},
            {"\"run_type\": \"aggregate\",$", MR_Next},
            {"\"repetitions\": 3,$", MR_Next},
@@ -604,6 +638,7 @@ ADD_CASES(TC_JSONOut,
            {"\"aggregate_name\": \"median\",$", MR_Next},
            {"\"iterations\": 3,$", MR_Next},
            {"\"name\": \"BM_SummaryRepeat/repeats:3_stddev\",$"},
+           {"\"family_index\": 19,$", MR_Next},
            {"\"run_name\": \"BM_SummaryRepeat/repeats:3\",$", MR_Next},
            {"\"run_type\": \"aggregate\",$", MR_Next},
            {"\"repetitions\": 3,$", MR_Next},
@@ -632,6 +667,7 @@ ADD_CASES(
 ADD_CASES(TC_JSONOut,
           {{".*BM_SummaryDisplay/repeats:2 ", MR_Not},
            {"\"name\": \"BM_SummaryDisplay/repeats:2_mean\",$"},
+           {"\"family_index\": 20,$", MR_Next},
            {"\"run_name\": \"BM_SummaryDisplay/repeats:2\",$", MR_Next},
            {"\"run_type\": \"aggregate\",$", MR_Next},
            {"\"repetitions\": 2,$", MR_Next},
@@ -639,6 +675,7 @@ ADD_CASES(TC_JSONOut,
            {"\"aggregate_name\": \"mean\",$", MR_Next},
            {"\"iterations\": 2,$", MR_Next},
            {"\"name\": \"BM_SummaryDisplay/repeats:2_median\",$"},
+           {"\"family_index\": 20,$", MR_Next},
            {"\"run_name\": \"BM_SummaryDisplay/repeats:2\",$", MR_Next},
            {"\"run_type\": \"aggregate\",$", MR_Next},
            {"\"repetitions\": 2,$", MR_Next},
@@ -646,6 +683,7 @@ ADD_CASES(TC_JSONOut,
            {"\"aggregate_name\": \"median\",$", MR_Next},
            {"\"iterations\": 2,$", MR_Next},
            {"\"name\": \"BM_SummaryDisplay/repeats:2_stddev\",$"},
+           {"\"family_index\": 20,$", MR_Next},
            {"\"run_name\": \"BM_SummaryDisplay/repeats:2\",$", MR_Next},
            {"\"run_type\": \"aggregate\",$", MR_Next},
            {"\"repetitions\": 2,$", MR_Next},
@@ -678,6 +716,7 @@ ADD_CASES(
 ADD_CASES(TC_JSONOut,
           {{".*BM_RepeatTimeUnit/repeats:3 ", MR_Not},
            {"\"name\": \"BM_RepeatTimeUnit/repeats:3_mean\",$"},
+           {"\"family_index\": 21,$", MR_Next},
            {"\"run_name\": \"BM_RepeatTimeUnit/repeats:3\",$", MR_Next},
            {"\"run_type\": \"aggregate\",$", MR_Next},
            {"\"repetitions\": 3,$", MR_Next},
@@ -686,6 +725,7 @@ ADD_CASES(TC_JSONOut,
            {"\"iterations\": 3,$", MR_Next},
            {"\"time_unit\": \"us\",?$"},
            {"\"name\": \"BM_RepeatTimeUnit/repeats:3_median\",$"},
+           {"\"family_index\": 21,$", MR_Next},
            {"\"run_name\": \"BM_RepeatTimeUnit/repeats:3\",$", MR_Next},
            {"\"run_type\": \"aggregate\",$", MR_Next},
            {"\"repetitions\": 3,$", MR_Next},
@@ -694,6 +734,7 @@ ADD_CASES(TC_JSONOut,
            {"\"iterations\": 3,$", MR_Next},
            {"\"time_unit\": \"us\",?$"},
            {"\"name\": \"BM_RepeatTimeUnit/repeats:3_stddev\",$"},
+           {"\"family_index\": 21,$", MR_Next},
            {"\"run_name\": \"BM_RepeatTimeUnit/repeats:3\",$", MR_Next},
            {"\"run_type\": \"aggregate\",$", MR_Next},
            {"\"repetitions\": 3,$", MR_Next},
@@ -746,6 +787,7 @@ ADD_CASES(TC_ConsoleOut, {{"^BM_UserStats/iterations:5/repeats:3/manual_time [ "
 ADD_CASES(
     TC_JSONOut,
     {{"\"name\": \"BM_UserStats/iterations:5/repeats:3/manual_time\",$"},
+     {"\"family_index\": 22,$", MR_Next},
      {"\"run_name\": \"BM_UserStats/iterations:5/repeats:3/manual_time\",$",
       MR_Next},
      {"\"run_type\": \"iteration\",$", MR_Next},
@@ -755,6 +797,7 @@ ADD_CASES(
      {"\"iterations\": 5,$", MR_Next},
      {"\"real_time\": 1\\.5(0)*e\\+(0)*2,$", MR_Next},
      {"\"name\": \"BM_UserStats/iterations:5/repeats:3/manual_time\",$"},
+     {"\"family_index\": 22,$", MR_Next},
      {"\"run_name\": \"BM_UserStats/iterations:5/repeats:3/manual_time\",$",
       MR_Next},
      {"\"run_type\": \"iteration\",$", MR_Next},
@@ -764,6 +807,7 @@ ADD_CASES(
      {"\"iterations\": 5,$", MR_Next},
      {"\"real_time\": 1\\.5(0)*e\\+(0)*2,$", MR_Next},
      {"\"name\": \"BM_UserStats/iterations:5/repeats:3/manual_time\",$"},
+     {"\"family_index\": 22,$", MR_Next},
      {"\"run_name\": \"BM_UserStats/iterations:5/repeats:3/manual_time\",$",
       MR_Next},
      {"\"run_type\": \"iteration\",$", MR_Next},
@@ -773,6 +817,7 @@ ADD_CASES(
      {"\"iterations\": 5,$", MR_Next},
      {"\"real_time\": 1\\.5(0)*e\\+(0)*2,$", MR_Next},
      {"\"name\": \"BM_UserStats/iterations:5/repeats:3/manual_time_mean\",$"},
+     {"\"family_index\": 22,$", MR_Next},
      {"\"run_name\": \"BM_UserStats/iterations:5/repeats:3/manual_time\",$",
       MR_Next},
      {"\"run_type\": \"aggregate\",$", MR_Next},
@@ -782,6 +827,7 @@ ADD_CASES(
      {"\"iterations\": 3,$", MR_Next},
      {"\"real_time\": 1\\.5(0)*e\\+(0)*2,$", MR_Next},
      {"\"name\": \"BM_UserStats/iterations:5/repeats:3/manual_time_median\",$"},
+     {"\"family_index\": 22,$", MR_Next},
      {"\"run_name\": \"BM_UserStats/iterations:5/repeats:3/manual_time\",$",
       MR_Next},
      {"\"run_type\": \"aggregate\",$", MR_Next},
@@ -791,6 +837,7 @@ ADD_CASES(
      {"\"iterations\": 3,$", MR_Next},
      {"\"real_time\": 1\\.5(0)*e\\+(0)*2,$", MR_Next},
      {"\"name\": \"BM_UserStats/iterations:5/repeats:3/manual_time_stddev\",$"},
+     {"\"family_index\": 22,$", MR_Next},
      {"\"run_name\": \"BM_UserStats/iterations:5/repeats:3/manual_time\",$",
       MR_Next},
      {"\"run_type\": \"aggregate\",$", MR_Next},
@@ -800,6 +847,7 @@ ADD_CASES(
      {"\"iterations\": 3,$", MR_Next},
      {"\"real_time\": %float,$", MR_Next},
      {"\"name\": \"BM_UserStats/iterations:5/repeats:3/manual_time_\",$"},
+     {"\"family_index\": 22,$", MR_Next},
      {"\"run_name\": \"BM_UserStats/iterations:5/repeats:3/manual_time\",$",
       MR_Next},
      {"\"run_type\": \"aggregate\",$", MR_Next},
@@ -831,6 +879,7 @@ void BM_JSON_Format(benchmark::State& state) {
 }
 BENCHMARK(BM_JSON_Format);
 ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_JSON_Format\",$"},
+                       {"\"family_index\": 23,$", MR_Next},
                        {"\"run_name\": \"BM_JSON_Format\",$", MR_Next},
                        {"\"run_type\": \"iteration\",$", MR_Next},
                        {"\"repetitions\": 1,$", MR_Next},
diff --git a/test/user_counters_tabular_test.cc b/test/user_counters_tabular_test.cc
index d49ce55..056923e 100644
--- a/test/user_counters_tabular_test.cc
+++ b/test/user_counters_tabular_test.cc
@@ -71,6 +71,7 @@ void BM_Counters_Tabular(benchmark::State& state) {
 BENCHMARK(BM_Counters_Tabular)->ThreadRange(1, 16);
 ADD_CASES(TC_JSONOut,
           {{"\"name\": \"BM_Counters_Tabular/threads:%int\",$"},
+           {"\"family_index\": 0,$", MR_Next},
            {"\"run_name\": \"BM_Counters_Tabular/threads:%int\",$", MR_Next},
            {"\"run_type\": \"iteration\",$", MR_Next},
            {"\"repetitions\": 1,$", MR_Next},
@@ -123,6 +124,7 @@ void BM_CounterRates_Tabular(benchmark::State& state) {
 BENCHMARK(BM_CounterRates_Tabular)->ThreadRange(1, 16);
 ADD_CASES(TC_JSONOut,
           {{"\"name\": \"BM_CounterRates_Tabular/threads:%int\",$"},
+           {"\"family_index\": 1,$", MR_Next},
            {"\"run_name\": \"BM_CounterRates_Tabular/threads:%int\",$",
             MR_Next},
            {"\"run_type\": \"iteration\",$", MR_Next},
@@ -174,6 +176,7 @@ void BM_CounterSet0_Tabular(benchmark::State& state) {
 BENCHMARK(BM_CounterSet0_Tabular)->ThreadRange(1, 16);
 ADD_CASES(TC_JSONOut,
           {{"\"name\": \"BM_CounterSet0_Tabular/threads:%int\",$"},
+           {"\"family_index\": 2,$", MR_Next},
            {"\"run_name\": \"BM_CounterSet0_Tabular/threads:%int\",$", MR_Next},
            {"\"run_type\": \"iteration\",$", MR_Next},
            {"\"repetitions\": 1,$", MR_Next},
@@ -212,6 +215,7 @@ void BM_CounterSet1_Tabular(benchmark::State& state) {
 BENCHMARK(BM_CounterSet1_Tabular)->ThreadRange(1, 16);
 ADD_CASES(TC_JSONOut,
           {{"\"name\": \"BM_CounterSet1_Tabular/threads:%int\",$"},
+           {"\"family_index\": 3,$", MR_Next},
            {"\"run_name\": \"BM_CounterSet1_Tabular/threads:%int\",$", MR_Next},
            {"\"run_type\": \"iteration\",$", MR_Next},
            {"\"repetitions\": 1,$", MR_Next},
@@ -254,6 +258,7 @@ void BM_CounterSet2_Tabular(benchmark::State& state) {
 BENCHMARK(BM_CounterSet2_Tabular)->ThreadRange(1, 16);
 ADD_CASES(TC_JSONOut,
           {{"\"name\": \"BM_CounterSet2_Tabular/threads:%int\",$"},
+           {"\"family_index\": 4,$", MR_Next},
            {"\"run_name\": \"BM_CounterSet2_Tabular/threads:%int\",$", MR_Next},
            {"\"run_type\": \"iteration\",$", MR_Next},
            {"\"repetitions\": 1,$", MR_Next},
diff --git a/test/user_counters_test.cc b/test/user_counters_test.cc
index 4d53f5c..29b33f2 100644
--- a/test/user_counters_test.cc
+++ b/test/user_counters_test.cc
@@ -32,6 +32,7 @@ BENCHMARK(BM_Counters_Simple);
 ADD_CASES(TC_ConsoleOut,
           {{"^BM_Counters_Simple %console_report bar=%hrfloat foo=%hrfloat$"}});
 ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_Counters_Simple\",$"},
+                       {"\"family_index\": 0,$", MR_Next},
                        {"\"run_name\": \"BM_Counters_Simple\",$", MR_Next},
                        {"\"run_type\": \"iteration\",$", MR_Next},
                        {"\"repetitions\": 1,$", MR_Next},
@@ -78,6 +79,7 @@ ADD_CASES(TC_ConsoleOut, {{"^BM_Counters_WithBytesAndItemsPSec %console_report "
                            "foo=%hrfloat items_per_second=%hrfloat/s$"}});
 ADD_CASES(TC_JSONOut,
           {{"\"name\": \"BM_Counters_WithBytesAndItemsPSec\",$"},
+           {"\"family_index\": 1,$", MR_Next},
            {"\"run_name\": \"BM_Counters_WithBytesAndItemsPSec\",$", MR_Next},
            {"\"run_type\": \"iteration\",$", MR_Next},
            {"\"repetitions\": 1,$", MR_Next},
@@ -125,6 +127,7 @@ ADD_CASES(
     TC_ConsoleOut,
     {{"^BM_Counters_Rate %console_report bar=%hrfloat/s foo=%hrfloat/s$"}});
 ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_Counters_Rate\",$"},
+                       {"\"family_index\": 2,$", MR_Next},
                        {"\"run_name\": \"BM_Counters_Rate\",$", MR_Next},
                        {"\"run_type\": \"iteration\",$", MR_Next},
                        {"\"repetitions\": 1,$", MR_Next},
@@ -165,6 +168,7 @@ BENCHMARK(BM_Invert);
 ADD_CASES(TC_ConsoleOut,
           {{"^BM_Invert %console_report bar=%hrfloatu foo=%hrfloatk$"}});
 ADD_CASES(TC_JSONOut, {{"\"name\": \"BM_Invert\",$"},
+                       {"\"family_index\": 3,$", MR_Next},
                        {"\"run_name\": \"BM_Invert\",$", MR_Next},
                        {"\"run_type\": \"iteration\",$", MR_Next},
                        {"\"repetitions\": 1,$", MR_Next},
@@ -207,6 +211,7 @@ ADD_CASES(TC_ConsoleOut, {{"^BM_Counters_InvertedRate %console_report "
                            "bar=%hrfloats foo=%hrfloats$"}});
 ADD_CASES(TC_JSONOut,
           {{"\"name\": \"BM_Counters_InvertedRate\",$"},
+           {"\"family_index\": 4,$", MR_Next},
            {"\"run_name\": \"BM_Counters_InvertedRate\",$", MR_Next},
            {"\"run_type\": \"iteration\",$", MR_Next},
            {"\"repetitions\": 1,$", MR_Next},
@@ -246,6 +251,7 @@ ADD_CASES(TC_ConsoleOut, {{"^BM_Counters_Threads/threads:%int %console_report "
                            "bar=%hrfloat foo=%hrfloat$"}});
 ADD_CASES(TC_JSONOut,
           {{"\"name\": \"BM_Counters_Threads/threads:%int\",$"},
+           {"\"family_index\": 5,$", MR_Next},
            {"\"run_name\": \"BM_Counters_Threads/threads:%int\",$", MR_Next},
            {"\"run_type\": \"iteration\",$", MR_Next},
            {"\"repetitions\": 1,$", MR_Next},
@@ -285,6 +291,7 @@ ADD_CASES(TC_ConsoleOut, {{"^BM_Counters_AvgThreads/threads:%int "
                            "%console_report bar=%hrfloat foo=%hrfloat$"}});
 ADD_CASES(TC_JSONOut,
           {{"\"name\": \"BM_Counters_AvgThreads/threads:%int\",$"},
+           {"\"family_index\": 6,$", MR_Next},
            {"\"run_name\": \"BM_Counters_AvgThreads/threads:%int\",$", MR_Next},
            {"\"run_type\": \"iteration\",$", MR_Next},
            {"\"repetitions\": 1,$", MR_Next},
@@ -327,6 +334,7 @@ ADD_CASES(TC_ConsoleOut, {{"^BM_Counters_AvgThreadsRate/threads:%int "
                            "%console_report bar=%hrfloat/s foo=%hrfloat/s$"}});
 ADD_CASES(TC_JSONOut,
           {{"\"name\": \"BM_Counters_AvgThreadsRate/threads:%int\",$"},
+           {"\"family_index\": 7,$", MR_Next},
            {"\"run_name\": \"BM_Counters_AvgThreadsRate/threads:%int\",$",
             MR_Next},
            {"\"run_type\": \"iteration\",$", MR_Next},
@@ -367,6 +375,7 @@ ADD_CASES(TC_ConsoleOut, {{"^BM_Counters_IterationInvariant %console_report "
                            "bar=%hrfloat foo=%hrfloat$"}});
 ADD_CASES(TC_JSONOut,
           {{"\"name\": \"BM_Counters_IterationInvariant\",$"},
+           {"\"family_index\": 8,$", MR_Next},
            {"\"run_name\": \"BM_Counters_IterationInvariant\",$", MR_Next},
            {"\"run_type\": \"iteration\",$", MR_Next},
            {"\"repetitions\": 1,$", MR_Next},
@@ -412,6 +421,7 @@ ADD_CASES(TC_ConsoleOut, {{"^BM_Counters_kIsIterationInvariantRate "
                            "%console_report bar=%hrfloat/s foo=%hrfloat/s$"}});
 ADD_CASES(TC_JSONOut,
           {{"\"name\": \"BM_Counters_kIsIterationInvariantRate\",$"},
+           {"\"family_index\": 9,$", MR_Next},
            {"\"run_name\": \"BM_Counters_kIsIterationInvariantRate\",$",
             MR_Next},
            {"\"run_type\": \"iteration\",$", MR_Next},
@@ -455,6 +465,7 @@ ADD_CASES(TC_ConsoleOut, {{"^BM_Counters_AvgIterations %console_report "
                            "bar=%hrfloat foo=%hrfloat$"}});
 ADD_CASES(TC_JSONOut,
           {{"\"name\": \"BM_Counters_AvgIterations\",$"},
+           {"\"family_index\": 10,$", MR_Next},
            {"\"run_name\": \"BM_Counters_AvgIterations\",$", MR_Next},
            {"\"run_type\": \"iteration\",$", MR_Next},
            {"\"repetitions\": 1,$", MR_Next},
@@ -498,6 +509,7 @@ ADD_CASES(TC_ConsoleOut, {{"^BM_Counters_kAvgIterationsRate "
                            "%console_report bar=%hrfloat/s foo=%hrfloat/s$"}});
 ADD_CASES(TC_JSONOut,
           {{"\"name\": \"BM_Counters_kAvgIterationsRate\",$"},
+           {"\"family_index\": 11,$", MR_Next},
            {"\"run_name\": \"BM_Counters_kAvgIterationsRate\",$", MR_Next},
            {"\"run_type\": \"iteration\",$", MR_Next},
            {"\"repetitions\": 1,$", MR_Next},
diff --git a/test/user_counters_thousands_test.cc b/test/user_counters_thousands_test.cc
index 21d8285..842b366 100644
--- a/test/user_counters_thousands_test.cc
+++ b/test/user_counters_thousands_test.cc
@@ -51,6 +51,7 @@ ADD_CASES(
     });
 ADD_CASES(TC_JSONOut,
           {{"\"name\": \"BM_Counters_Thousands/repeats:2\",$"},
+           {"\"family_index\": 0,$", MR_Next},
            {"\"run_name\": \"BM_Counters_Thousands/repeats:2\",$", MR_Next},
            {"\"run_type\": \"iteration\",$", MR_Next},
            {"\"repetitions\": 2,$", MR_Next},
@@ -68,6 +69,7 @@ ADD_CASES(TC_JSONOut,
            {"}", MR_Next}});
 ADD_CASES(TC_JSONOut,
           {{"\"name\": \"BM_Counters_Thousands/repeats:2\",$"},
+           {"\"family_index\": 0,$", MR_Next},
            {"\"run_name\": \"BM_Counters_Thousands/repeats:2\",$", MR_Next},
            {"\"run_type\": \"iteration\",$", MR_Next},
            {"\"repetitions\": 2,$", MR_Next},
@@ -85,6 +87,7 @@ ADD_CASES(TC_JSONOut,
            {"}", MR_Next}});
 ADD_CASES(TC_JSONOut,
           {{"\"name\": \"BM_Counters_Thousands/repeats:2_mean\",$"},
+           {"\"family_index\": 0,$", MR_Next},
            {"\"run_name\": \"BM_Counters_Thousands/repeats:2\",$", MR_Next},
            {"\"run_type\": \"aggregate\",$", MR_Next},
            {"\"repetitions\": 2,$", MR_Next},
@@ -102,6 +105,7 @@ ADD_CASES(TC_JSONOut,
            {"}", MR_Next}});
 ADD_CASES(TC_JSONOut,
           {{"\"name\": \"BM_Counters_Thousands/repeats:2_median\",$"},
+           {"\"family_index\": 0,$", MR_Next},
            {"\"run_name\": \"BM_Counters_Thousands/repeats:2\",$", MR_Next},
            {"\"run_type\": \"aggregate\",$", MR_Next},
            {"\"repetitions\": 2,$", MR_Next},
@@ -119,6 +123,7 @@ ADD_CASES(TC_JSONOut,
            {"}", MR_Next}});
 ADD_CASES(TC_JSONOut,
           {{"\"name\": \"BM_Counters_Thousands/repeats:2_stddev\",$"},
+           {"\"family_index\": 0,$", MR_Next},
            {"\"run_name\": \"BM_Counters_Thousands/repeats:2\",$", MR_Next},
            {"\"run_type\": \"aggregate\",$", MR_Next},
            {"\"repetitions\": 2,$", MR_Next},