switch perf and ll_prof loggers to line buffering

src/log.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/log.h"
 
 #include <cstdarg>
 #include <sstream>
 
 #include "src/bailout-reason.h"
@@ skipping 223 matching lines @@
                            SharedFunctionInfo* shared) override {}
 
  private:
   void LogRecordedBuffer(AbstractCode* code, SharedFunctionInfo* shared,
                          const char* name, int length) override;
 
   // Extension added to V8 log file name to get the low-level log name.
   static const char kFilenameFormatString[];
   static const int kFilenameBufferPadding;
 
-  // File buffer size of the low-level log. We don't use the default to
-  // minimize the associated overhead.
-  static const int kLogBufferSize = 2 * MB;
-
   FILE* perf_output_handle_;
 };
 
 const char PerfBasicLogger::kFilenameFormatString[] = "/tmp/perf-%d.map";
 // Extra space for the PID in the filename
 const int PerfBasicLogger::kFilenameBufferPadding = 16;
 
 PerfBasicLogger::PerfBasicLogger()
     : perf_output_handle_(NULL) {
   // Open the perf JIT dump file.
   int bufferSize = sizeof(kFilenameFormatString) + kFilenameBufferPadding;
   ScopedVector<char> perf_dump_name(bufferSize);
   int size = SNPrintF(
       perf_dump_name,
       kFilenameFormatString,
       base::OS::GetCurrentProcessId());
   CHECK_NE(size, -1);
   perf_output_handle_ =
       base::OS::FOpen(perf_dump_name.start(), base::OS::LogFileOpenMode);
   CHECK_NOT_NULL(perf_output_handle_);
-  setvbuf(perf_output_handle_, NULL, _IOFBF, kLogBufferSize);
+  setvbuf(perf_output_handle_, NULL, _IOLBF, 0);
 }
 
 
 PerfBasicLogger::~PerfBasicLogger() {
   fclose(perf_output_handle_);
   perf_output_handle_ = NULL;
 }
 
 void PerfBasicLogger::LogRecordedBuffer(AbstractCode* code, SharedFunctionInfo*,
                                         const char* name, int length) {
@@ skipping 50 matching lines @@
     Address to_address;
   };
 
 
   static const char kCodeMovingGCTag = 'G';
 
 
   // Extension added to V8 log file name to get the low-level log name.
   static const char kLogExt[];
 
-  // File buffer size of the low-level log. We don't use the default to
-  // minimize the associated overhead.
-  static const int kLogBufferSize = 2 * MB;
-
   void LogCodeInfo();
   void LogWriteBytes(const char* bytes, int size);
 
   template <typename T>
   void LogWriteStruct(const T& s) {
     char tag = T::kTag;
     LogWriteBytes(reinterpret_cast<const char*>(&tag), sizeof(tag));
     LogWriteBytes(reinterpret_cast<const char*>(&s), sizeof(s));
   }
 
   FILE* ll_output_handle_;
 };
 
 const char LowLevelLogger::kLogExt[] = ".ll";
 
 LowLevelLogger::LowLevelLogger(const char* name)
     : ll_output_handle_(NULL) {
   // Open the low-level log file.
   size_t len = strlen(name);
   ScopedVector<char> ll_name(static_cast<int>(len + sizeof(kLogExt)));
   MemCopy(ll_name.start(), name, len);
   MemCopy(ll_name.start() + len, kLogExt, sizeof(kLogExt));
   ll_output_handle_ =
       base::OS::FOpen(ll_name.start(), base::OS::LogFileOpenMode);
-  setvbuf(ll_output_handle_, NULL, _IOFBF, kLogBufferSize);
+  setvbuf(ll_output_handle_, NULL, _IOLBF, 0);
 
   LogCodeInfo();
 }
 
 
 LowLevelLogger::~LowLevelLogger() {
   fclose(ll_output_handle_);
   ll_output_handle_ = NULL;
 }
 
@@ skipping 1525 matching lines @@
     removeCodeEventListener(jit_logger_);
     delete jit_logger_;
     jit_logger_ = NULL;
   }
 
   return log_->Close();
 }
 
 }  // namespace internal
 }  // namespace v8