Revert "Merge "tests: perf: measure coroutines performance" from Benny"

This reverts commit 7217fd1, reversing
changes made to 5d1975c. It does not
build in C++17 mode.

CMakeLists.txt

@@ -1051,8 +1051,7 @@ if (Seastar_INSTALL OR Seastar_TESTING)
   add_library(seastar_perf_testing
     src/testing/random.cc
     include/seastar/testing/perf_tests.hh
-    tests/perf/perf_tests.cc
-    tests/perf/linux_perf_event.cc)
+    tests/perf/perf_tests.cc)
   add_library (Seastar::seastar_perf_testing ALIAS seastar_perf_testing)
   target_compile_definitions (seastar_perf_testing
     PRIVATE ${Seastar_PRIVATE_COMPILE_DEFINITIONS})

include/seastar/testing/perf_tests.hh

@@ -28,11 +28,6 @@
 
 #include <seastar/core/future.hh>
 #include <seastar/core/loop.hh>
-#include <seastar/testing/linux_perf_event.hh>
-
-#ifdef SEASTAR_COROUTINES_ENABLED
-#include <seastar/core/coroutine.hh>
-#endif
 
 using namespace seastar;
 
@@ -43,86 +38,14 @@ struct config;
 
 using clock_type = std::chrono::steady_clock;
 
-class perf_stats {
-public:
-    uint64_t allocations = 0;
-    uint64_t tasks_executed = 0;
-    uint64_t instructions_retired = 0;
-
-private:
-    static uint64_t perf_mallocs();
-    static uint64_t perf_tasks_processed();
-
-public:
-    perf_stats() = default;
-    perf_stats(uint64_t allocations_, uint64_t tasks_executed_, uint64_t instructions_retired_ = 0)
-        : allocations(allocations_)
-        , tasks_executed(tasks_executed_)
-        , instructions_retired(instructions_retired_)
-    {}
-    perf_stats(perf_stats&& o) noexcept
-        : allocations(std::exchange(o.allocations, 0))
-        , tasks_executed(std::exchange(o.tasks_executed, 0))
-        , instructions_retired(std::exchange(o.instructions_retired, 0))
-    {}
-    perf_stats(const perf_stats& o) = default;
-
-    perf_stats& operator=(perf_stats&& o) = default;
-    perf_stats& operator=(const perf_stats& o) = default;
-
-    perf_stats& operator+=(perf_stats b);
-    perf_stats& operator-=(perf_stats b);
-
-    static perf_stats snapshot(linux_perf_event* instructions_retired_counter = nullptr);
-};
-
-inline
-perf_stats
-operator+(perf_stats a, perf_stats b) {
-    a.allocations += b.allocations;
-    a.tasks_executed += b.tasks_executed;
-    a.instructions_retired += b.instructions_retired;
-    return a;
-}
-
-inline
-perf_stats
-operator-(perf_stats a, perf_stats b) {
-    a.allocations -= b.allocations;
-    a.tasks_executed -= b.tasks_executed;
-    a.instructions_retired -= b.instructions_retired;
-    return a;
-}
-
-inline perf_stats& perf_stats::operator+=(perf_stats b) {
-    allocations += b.allocations;
-    tasks_executed += b.tasks_executed;
-    instructions_retired += b.instructions_retired;
-    return *this;
-}
-
-inline perf_stats& perf_stats::operator-=(perf_stats b) {
-    allocations -= b.allocations;
-    tasks_executed -= b.tasks_executed;
-    instructions_retired -= b.instructions_retired;
-    return *this;
-}
-
 class performance_test {
     std::string _test_case;
     std::string _test_group;
 
     uint64_t _single_run_iterations = 0;
     std::atomic<uint64_t> _max_single_run_iterations;
-protected:
-    linux_perf_event _instructions_retired_counter = linux_perf_event::user_instructions_retired();
 private:
     void do_run(const config&);
-public:
-    struct run_result {
-        clock_type::duration duration;
-        perf_stats stats;
-    };
 protected:
     [[gnu::always_inline]] [[gnu::hot]]
     bool stop_iteration() const {
@@ -136,7 +59,7 @@ protected:
 
     virtual void set_up() = 0;
     virtual void tear_down() noexcept = 0;
-    virtual future<run_result> do_single_run() = 0;
+    virtual future<clock_type::duration> do_single_run() = 0;
 public:
     performance_test(const std::string& test_case, const std::string& test_group)
         : _test_case(test_case)
@@ -163,47 +86,33 @@ class time_measurement {
     clock_type::time_point _run_start_time;
     clock_type::time_point _start_time;
     clock_type::duration _total_time;
-
-    perf_stats _start_stats;
-    perf_stats _total_stats;
-
 public:
     [[gnu::always_inline]] [[gnu::hot]]
-    void start_run(linux_perf_event* instructions_retired_counter = nullptr) {
+    void start_run() {
         _total_time = { };
         auto t = clock_type::now();
         _run_start_time = t;
         _start_time = t;
-        _start_stats = perf_stats::snapshot(instructions_retired_counter);
     }
 
     [[gnu::always_inline]] [[gnu::hot]]
-    performance_test::run_result stop_run(linux_perf_event* instructions_retired_counter = nullptr) {
+    clock_type::duration stop_run() {
         auto t = clock_type::now();
-        performance_test::run_result ret;
         if (_start_time == _run_start_time) {
-            ret.duration = t - _start_time;
-            auto stats = perf_stats::snapshot(instructions_retired_counter);
-            ret.stats = stats - _start_stats;
-        } else {
-            ret.duration = _total_time;
-            ret.stats = _total_stats;
+            return t - _start_time;
         }
-        return ret;
+        return _total_time;
     }
 
     [[gnu::always_inline]] [[gnu::hot]]
-    void start_iteration(linux_perf_event* instructions_retired_counter = nullptr) {
+    void start_iteration() {
         _start_time = clock_type::now();
-        _start_stats = perf_stats::snapshot(instructions_retired_counter);
     }
 
     [[gnu::always_inline]] [[gnu::hot]]
-    void stop_iteration(linux_perf_event* instructions_retired_counter = nullptr) {
+    void stop_iteration() {
         auto t = clock_type::now();
         _total_time += t - _start_time;
-        auto stats = perf_stats::snapshot(instructions_retired_counter);
-        _total_stats += stats - _start_stats;
     }
 };
 
@@ -253,11 +162,10 @@ protected:
     }
 
     [[gnu::hot]]
-    virtual future<run_result> do_single_run() override {
+    virtual future<clock_type::duration> do_single_run() override {
         // Redundant 'this->'s courtesy of https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61636
-        _instructions_retired_counter.enable();
         return if_constexpr_<is_future<decltype(_test->run())>::value>([&] (auto&&...) {
-            measure_time.start_run(&_instructions_retired_counter);
+            measure_time.start_run();
             return do_until([this] { return this->stop_iteration(); }, [this] {
                 return if_constexpr_<std::is_same<decltype(_test->run()), future<>>::value>([&] (auto&&...) {
                     this->next_iteration(1);
@@ -269,13 +177,11 @@ protected:
                         this->next_iteration(n);
                     });
                 })();
-            }).then([this] {
-                return measure_time.stop_run(&_instructions_retired_counter);
-            }).finally([this] {
-                _instructions_retired_counter.disable();
+            }).then([] {
+                return measure_time.stop_run();
             });
         }, [&] (auto&&...) {
-            measure_time.start_run(&_instructions_retired_counter);
+            measure_time.start_run();
             while (!stop_iteration()) {
                 if_constexpr_<std::is_void<decltype(_test->run())>::value>([&] (auto&&...) {
                     (void)_test->run();
@@ -286,9 +192,7 @@ protected:
                     this->next_iteration(run_test(dependency...));
                 })();
             }
-            auto ret = measure_time.stop_run(&_instructions_retired_counter);
-            _instructions_retired_counter.disable();
-            return make_ready_future<run_result>(std::move(ret));
+            return make_ready_future<clock_type::duration>(measure_time.stop_run());
         })();
     }
 public:
@@ -330,8 +234,6 @@ void do_not_optimize(const T& v)
 
 // PERF_TEST and PERF_TEST_F support both synchronous and asynchronous functions.
 // The former should return `void`, the latter `future<>`.
-// PERF_TEST_C executes a coroutine function, if enabled.
-// PERF_TEST_CN executes a coroutine function, if enabled, returning the number of inner-loops.
 //
 // Test cases may perform multiple operations in a single run, this may be desirable
 // if the cost of an individual operation is very small. This allows measuring either
@@ -355,23 +257,3 @@ void do_not_optimize(const T& v)
     static ::perf_tests::internal::test_registrar<test_##test_group##_##test_case> \
     test_##test_group##_##test_case##_registrar(#test_group, #test_case); \
     [[gnu::always_inline]] auto test_##test_group##_##test_case::run()
-
-#ifdef SEASTAR_COROUTINES_ENABLED
-
-#define PERF_TEST_C(test_group, test_case) \
-    struct test_##test_group##_##test_case : test_group { \
-        inline future<> run(); \
-    }; \
-    static ::perf_tests::internal::test_registrar<test_##test_group##_##test_case> \
-    test_##test_group##_##test_case##_registrar(#test_group, #test_case); \
-    future<> test_##test_group##_##test_case::run()
-
-#define PERF_TEST_CN(test_group, test_case) \
-    struct test_##test_group##_##test_case : test_group { \
-        inline future<size_t> run(); \
-    }; \
-    static ::perf_tests::internal::test_registrar<test_##test_group##_##test_case> \
-    test_##test_group##_##test_case##_registrar(#test_group, #test_case); \
-    future<size_t> test_##test_group##_##test_case::run()
-
-#endif // SEASTAR_COROUTINES_ENABLED

tests/perf/CMakeLists.txt

@@ -76,6 +76,3 @@ seastar_add_test (rpc
 seastar_add_test (smp_submit_to
   SOURCES smp_submit_to_perf.cc
   NO_SEASTAR_PERF_TESTING_LIBRARY)
-
-seastar_add_test (coroutine
-  SOURCES coroutine_perf.cc)