bench: Add --sanity-check flag, use it in make check

The benchmarks are run as part of `make check` for a minimum sanity
check. The actual results are being ignored. So only run them for one
iteration.

This makes the `bench_bitcoin` part take 2m00 instead of 5m20 here.
Which is still too long (imo), but this needs to be solved in the
`WalletLoading*` benchmarks which take that long per iteration.

src/Makefile.test.include

@@ -364,8 +364,8 @@ endif
 if TARGET_WINDOWS
 else
 if ENABLE_BENCH
-	@echo "Running bench/bench_bitcoin ..."
+	@echo "Running bench/bench_bitcoin (one iteration sanity check)..."
-	$(BENCH_BINARY) > /dev/null
+	$(BENCH_BINARY) --sanity-check > /dev/null
 endif
 endif
 	$(AM_V_at)$(MAKE) $(AM_MAKEFLAGS) -C secp256k1 check

src/bench/bench.cpp

@@ -57,6 +57,10 @@ void benchmark::BenchRunner::RunAll(const Args& args)
     std::regex reFilter(args.regex_filter);
     std::smatch baseMatch;
 
+    if (args.sanity_check) {
+        std::cout << "Running with --sanity check option, benchmark results will be useless." << std::endl;
+    }
+
     std::vector<ankerl::nanobench::Result> benchmarkResults;
     for (const auto& p : benchmarks()) {
         if (!std::regex_match(p.first, baseMatch, reFilter)) {
@@ -69,6 +73,9 @@ void benchmark::BenchRunner::RunAll(const Args& args)
         }
 
         Bench bench;
+        if (args.sanity_check) {
+            bench.epochs(1).epochIterations(1);
+        }
         bench.name(p.first);
         if (args.min_time > 0ms) {
             // convert to nanos before dividing to reduce rounding errors

src/bench/bench.h

@@ -43,6 +43,7 @@ typedef std::function<void(Bench&)> BenchFunction;
 
 struct Args {
     bool is_list_only;
+    bool sanity_check;
     std::chrono::milliseconds min_time;
     std::vector<double> asymptote;
     fs::path output_csv;

src/bench/bench_bitcoin.cpp

@@ -29,6 +29,7 @@ static void SetupBenchArgs(ArgsManager& argsman)
     argsman.AddArg("-min_time=<milliseconds>", strprintf("Minimum runtime per benchmark, in milliseconds (default: %d)", DEFAULT_MIN_TIME_MS), ArgsManager::ALLOW_ANY | ArgsManager::DISALLOW_NEGATION, OptionsCategory::OPTIONS);
     argsman.AddArg("-output_csv=<output.csv>", "Generate CSV file with the most important benchmark results", ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     argsman.AddArg("-output_json=<output.json>", "Generate JSON file with all benchmark results", ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
+    argsman.AddArg("-sanity-check", "Run benchmarks for only one iteration", ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
 }
 
 // parses a comma separated list like "10,20,30,50"
@@ -112,6 +113,7 @@ int main(int argc, char** argv)
     args.output_csv = argsman.GetPathArg("-output_csv");
     args.output_json = argsman.GetPathArg("-output_json");
     args.regex_filter = argsman.GetArg("-filter", DEFAULT_BENCH_FILTER);
+    args.sanity_check = argsman.GetBoolArg("-sanity-check", false);
 
     benchmark::BenchRunner::RunAll(args);