Merge "simpleperf: fix unit test."

am: bee9bac65f

Change-Id: Ic4fd3dd53843d206a2537137049888d1ffb61c01

4 files changed, 48 insertions, 14 deletions

diff --git a/simpleperf/IOEventLoop.cpp b/simpleperf/IOEventLoop.cpp
index ce259280..c92170e5 100644
--- a/simpleperf/IOEventLoop.cpp
+++ b/simpleperf/IOEventLoop.cpp
@@ -37,7 +37,7 @@ struct IOEvent {
   }
 };
 
-IOEventLoop::IOEventLoop() : ebase_(nullptr), has_error_(false) {}
+IOEventLoop::IOEventLoop() : ebase_(nullptr), has_error_(false), use_precise_timer_(false) {}
 
 IOEventLoop::~IOEventLoop() {
   events_.clear();
@@ -46,11 +46,26 @@ IOEventLoop::~IOEventLoop() {
   }
 }
 
+bool IOEventLoop::UsePreciseTimer() {
+  if (ebase_ != nullptr) {
+    return false;  // Too late to set the flag.
+  }
+  use_precise_timer_ = true;
+  return true;
+}
+
 bool IOEventLoop::EnsureInit() {
   if (ebase_ == nullptr) {
-    ebase_ = event_base_new();
+    event_config* cfg = event_config_new();
+    if (cfg != nullptr) {
+      if (use_precise_timer_) {
+        event_config_set_flag(cfg, EVENT_BASE_FLAG_PRECISE_TIMER);
+      }
+      ebase_ = event_base_new_with_config(cfg);
+      event_config_free(cfg);
+    }
     if (ebase_ == nullptr) {
-      LOG(ERROR) << "failed to call event_base_new()";
+      LOG(ERROR) << "failed to create event_base";
       return false;
     }
   }
diff --git a/simpleperf/IOEventLoop.h b/simpleperf/IOEventLoop.h
index 9b966295..9dc73c3c 100644
--- a/simpleperf/IOEventLoop.h
+++ b/simpleperf/IOEventLoop.h
@@ -35,6 +35,9 @@ class IOEventLoop {
   IOEventLoop();
   ~IOEventLoop();
 
+  // Use precise timer for periodic events which want precision in ms.
+  bool UsePreciseTimer();
+
   // Register a read Event, so [callback] is called when [fd] can be read
   // without blocking. If registered successfully, return the reference
   // to control the Event, otherwise return nullptr.
@@ -81,6 +84,7 @@ class IOEventLoop {
   event_base* ebase_;
   std::vector<std::unique_ptr<IOEvent>> events_;
   bool has_error_;
+  bool use_precise_timer_;
 };
 
 #endif  // SIMPLE_PERF_IOEVENT_LOOP_H_
diff --git a/simpleperf/IOEventLoop_test.cpp b/simpleperf/IOEventLoop_test.cpp
index dc7a4dad..32535021 100644
--- a/simpleperf/IOEventLoop_test.cpp
+++ b/simpleperf/IOEventLoop_test.cpp
@@ -119,14 +119,17 @@ TEST(IOEventLoop, signal) {
   ASSERT_EQ(100, count);
 }
 
-TEST(IOEventLoop, periodic) {
+void TestPeriodicEvents(int period_in_us, int iterations, bool precise) {
   timeval tv;
-  tv.tv_sec = 0;
-  tv.tv_usec = 1000;
+  tv.tv_sec = period_in_us / 1000000;
+  tv.tv_usec = period_in_us % 1000000;
   int count = 0;
   IOEventLoop loop;
+  if (precise) {
+    ASSERT_TRUE(loop.UsePreciseTimer());
+  }
   ASSERT_TRUE(loop.AddPeriodicEvent(tv, [&]() {
-    if (++count == 100) {
+    if (++count == iterations) {
       loop.ExitLoop();
     }
     return true;
@@ -134,14 +137,21 @@ TEST(IOEventLoop, periodic) {
   auto start_time = std::chrono::steady_clock::now();
   ASSERT_TRUE(loop.RunLoop());
   auto end_time = std::chrono::steady_clock::now();
-  ASSERT_EQ(100, count);
+  ASSERT_EQ(iterations, count);
   double time_used = std::chrono::duration_cast<std::chrono::duration<double>>(
-                         end_time - start_time)
-                         .count();
-  // time_used is 0.1 if running precisely, and we accept small errors by using
-  // a range [0.1, 0.15).
-  ASSERT_GE(time_used, 0.1);
-  ASSERT_LT(time_used, 0.15);
+                         end_time - start_time).count();
+  double min_time_in_sec = period_in_us / 1e6 * iterations;
+  double max_time_in_sec = min_time_in_sec + (precise ? 0.1 : 1);
+  ASSERT_GE(time_used, min_time_in_sec);
+  ASSERT_LT(time_used, max_time_in_sec);
+}
+
+TEST(IOEventLoop, periodic) {
+  TestPeriodicEvents(1000000, 1, false);
+}
+
+TEST(IOEventLoop, periodic_precise) {
+  TestPeriodicEvents(1000, 100, true);
 }
 
 TEST(IOEventLoop, read_and_del_event) {
diff --git a/simpleperf/cmd_stat.cpp b/simpleperf/cmd_stat.cpp
index ddd83f7b..fce4fb14 100644
--- a/simpleperf/cmd_stat.cpp
+++ b/simpleperf/cmd_stat.cpp
@@ -427,6 +427,11 @@ bool StatCommand::Run(const std::vector<std::string>& args) {
     return false;
   }
   IOEventLoop* loop = event_selection_set_.GetIOEventLoop();
+  if (interval_in_ms_ != 0) {
+    if (!loop->UsePreciseTimer()) {
+      return false;
+    }
+  }
   if (!loop->AddSignalEvents({SIGCHLD, SIGINT, SIGTERM, SIGHUP},
                              [&]() { return loop->ExitLoop(); })) {
     return false;