Simplify ProfLazyMode test on Linux.

test/cctest/test-log.cc

Index: test/cctest/test-log.cc
diff --git a/test/cctest/test-log.cc b/test/cctest/test-log.cc
index 7168737416588efdde191ad876e5672f478c2469..710c10e996a8b235e6bed159febc683c275c4e64 100644
--- a/test/cctest/test-log.cc
+++ b/test/cctest/test-log.cc
@@ -139,6 +139,12 @@ namespace internal {
 class LoggerTestHelper : public AllStatic {
  public:
   static bool IsSamplerActive() { return Logger::IsProfilerSamplerActive(); }
+  static void ResetSamplesTaken() {
+    reinterpret_cast<Sampler*>(Logger::ticker_)->ResetSamplesTaken();
+  }
+  static bool has_samples_taken() {
+    return reinterpret_cast<Sampler*>(Logger::ticker_)->samples_taken() > 0;
+  }
 };
 
 }  // namespace v8::internal
@@ -147,24 +153,6 @@ class LoggerTestHelper : public AllStatic {
 using v8::internal::LoggerTestHelper;
 
 
-// Under Linux, we need to check if signals were delivered to avoid false
-// positives.  Under other platforms profiling is done via a high-priority
-// thread, so this case never happen.
-static bool was_sigprof_received = true;
-#ifdef __linux__
-
-struct sigaction old_sigprof_handler;
-pthread_t our_thread;
-
-static void SigProfSignalHandler(int signal, siginfo_t* info, void* context) {
-  if (signal != SIGPROF || !pthread_equal(pthread_self(), our_thread)) return;
-  was_sigprof_received = true;
-  old_sigprof_handler.sa_sigaction(signal, info, context);
-}
-
-#endif  // __linux__
-
-
 namespace {
 
 class ScopedLoggerInitializer {
@@ -258,6 +246,9 @@ class LogBufferMatcher {
 
 
 static void CheckThatProfilerWorks(LogBufferMatcher* matcher) {
+  CHECK(!LoggerTestHelper::IsSamplerActive());
+  LoggerTestHelper::ResetSamplesTaken();
+
   Logger::ResumeProfiler(v8::PROFILER_MODULE_CPU, 0);
   CHECK(LoggerTestHelper::IsSamplerActive());
 
@@ -266,19 +257,6 @@ static void CheckThatProfilerWorks(LogBufferMatcher* matcher) {
   const char* code_creation = "\ncode-creation,";  // eq. to /^code-creation,/
   CHECK_NE(NULL, matcher->Find(code_creation));
 
-#ifdef __linux__
-  // Intercept SIGPROF handler to make sure that the test process
-  // had received it. Under load, system can defer it causing test failure.
-  // It is important to execute this after 'ResumeProfiler'.
-  our_thread = pthread_self();
-  was_sigprof_received = false;
-  struct sigaction sa;
-  sa.sa_sigaction = SigProfSignalHandler;
-  sigemptyset(&sa.sa_mask);
-  sa.sa_flags = SA_SIGINFO;
-  CHECK_EQ(0, sigaction(SIGPROF, &sa, &old_sigprof_handler));
-#endif  // __linux__
-
   // Force compiler to generate new code by parametrizing source.
   EmbeddedVector<char, 100> script_src;
   i::OS::SNPrintF(script_src,
@@ -306,7 +284,7 @@ static void CheckThatProfilerWorks(LogBufferMatcher* matcher) {
   CHECK_NE(NULL, matcher->Find(code_creation));
   const char* tick = "\ntick,";
   const bool ticks_found = matcher->Find(tick) != NULL;
-  CHECK_EQ(was_sigprof_received, ticks_found);
+  CHECK_EQ(LoggerTestHelper::has_samples_taken(), ticks_found);
 }