Integer reader implementation optimization based on fast_float

eliaskosunen · Jan 9, 2024 · 629c3c5 · 629c3c5
1 parent f26b24d
commit 629c3c5
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Showing 10 changed files with 337 additions and 598 deletions.
diff --git a/benchmark/runtime/common/bench_helpers.h b/benchmark/runtime/common/bench_helpers.h
@@ -65,20 +65,18 @@ template <typename T>
 struct single_state {
     single_state(scn::span<std::string> src) : source(src), it(source.begin())
     {
-        values.reserve(2 << 12);
     }
 
     void reset_if_necessary()
     {
         if (it == source.end()) {
             it = source.begin();
-            values.clear();
         }
     }
 
     void push(T i)
     {
-        values.push_back(i);
+        benchmark::DoNotOptimize(i);
     }
 
     static int64_t get_bytes_processed(benchmark::State& state)
@@ -88,29 +86,24 @@ struct single_state {
 
     scn::span<std::string> source;
     typename scn::span<std::string>::iterator it;
-
-    std::vector<T> values;
 };
 
 template <typename T>
 struct repeated_state {
-    repeated_state(const std::string& src) : source(src), it(source.data())
-    {
-        values.reserve(2 << 12);
-    }
+    repeated_state(const std::string& src) : source(src), it(source.data()) {}
 
     void reset()
     {
         it = source.data();
-        values.clear();
     }
 
     auto source_end_addr() const
     {
         return scn::detail::to_address(source.end());
     }
 
-    void skip_classic_ascii_space() {
+    void skip_classic_ascii_space()
+    {
         for (; is_classic_ascii_space(*it); ++it) {}
         if (it == source_end_addr()) {
             reset();
@@ -124,7 +117,7 @@ struct repeated_state {
 
     void push(T i)
     {
-        values.push_back(i);
+        benchmark::DoNotOptimize(i);
     }
 
     static int64_t get_bytes_processed(benchmark::State& state)
@@ -134,6 +127,4 @@ struct repeated_state {
 
     const std::string& source;
     const char* it;
-
-    std::vector<T> values;
 };
diff --git a/benchmark/runtime/float/repeated.cpp b/benchmark/runtime/float/repeated.cpp
@@ -91,7 +91,7 @@ static void scan_float_repeated_sstream(benchmark::State& state)
 
         if (stream.eof()) {
             stream = std::istringstream(s.source);
-            s.values.clear();
+            s.reset();
         }
         else if (stream.fail()) {
             state.SkipWithError("Scan error");

diff --git a/benchmark/runtime/integer/repeated.cpp b/benchmark/runtime/integer/repeated.cpp
@@ -79,6 +79,34 @@ BENCHMARK_TEMPLATE(scan_int_repeated_scn_value, int);
 BENCHMARK_TEMPLATE(scan_int_repeated_scn_value, long long);
 BENCHMARK_TEMPLATE(scan_int_repeated_scn_value, unsigned);
 
+template <typename Int>
+static void scan_int_repeated_scn_decimal(benchmark::State& state)
+{
+    repeated_state<Int> s{get_integer_string<Int>()};
+
+    for (auto _ : state) {
+        auto result = scn::scan<Int>(s.view(), "{:d}");
+
+        if (!result) {
+            if (result.error() == scn::scan_error::end_of_range) {
+                s.reset();
+            }
+            else {
+                state.SkipWithError("Scan error");
+                break;
+            }
+        }
+        else {
+            s.push(result->value());
+            s.it = scn::detail::to_address(result->range().begin());
+        }
+    }
+    state.SetBytesProcessed(s.get_bytes_processed(state));
+}
+BENCHMARK_TEMPLATE(scan_int_repeated_scn_decimal, int);
+BENCHMARK_TEMPLATE(scan_int_repeated_scn_decimal, long long);
+BENCHMARK_TEMPLATE(scan_int_repeated_scn_decimal, unsigned);
+
 template <typename Int>
 static void scan_int_repeated_scn_int(benchmark::State& state)
 {
@@ -123,7 +151,7 @@ static void scan_int_repeated_sstream(benchmark::State& state)
 
         if (stream.eof()) {
             stream = std::istringstream(s.source);
-            s.values.clear();
+            s.reset();
         }
         else if (stream.fail()) {
             state.SkipWithError("Scan error");

diff --git a/benchmark/runtime/integer/single.cpp b/benchmark/runtime/integer/single.cpp
@@ -67,6 +67,28 @@ BENCHMARK_TEMPLATE(scan_int_single_scn_value, int);
 BENCHMARK_TEMPLATE(scan_int_single_scn_value, long long);
 BENCHMARK_TEMPLATE(scan_int_single_scn_value, unsigned);
 
+template <typename Int>
+static void scan_int_single_scn_decimal(benchmark::State& state)
+{
+    single_state<Int> s{get_integer_list<Int>()};
+
+    for (auto _ : state) {
+        s.reset_if_necessary();
+
+        if (auto result = scn::scan<Int>(*s.it, "{:d}"); !result) {
+            state.SkipWithError("Benchmark errored");
+            break;
+        }
+        else {
+            s.push(result->value());
+        }
+    }
+    state.SetBytesProcessed(s.get_bytes_processed(state));
+}
+BENCHMARK_TEMPLATE(scan_int_single_scn_decimal, int);
+BENCHMARK_TEMPLATE(scan_int_single_scn_decimal, long long);
+BENCHMARK_TEMPLATE(scan_int_single_scn_decimal, unsigned);
+
 template <typename Int>
 static void scan_int_single_scn_int(benchmark::State& state)
 {