Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Zero allocation fix #226

Merged
merged 1 commit into from
Oct 11, 2017
Merged

Zero allocation fix #226

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
17 changes: 9 additions & 8 deletions CMakeLists.txt
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -192,6 +192,11 @@ using namespace Outer::Inner;;
int main() { return i; }
" HAVE_NAMESPACES)

check_cxx_source_compiles ("
__thread int tls;
int main() { }
" HAVE_GCC_TLS)

check_cxx_source_compiles ("
__declspec(thread) int tls;
int main() { }
Expand All @@ -202,19 +207,15 @@ thread_local int tls;
int main() { }
" HAVE_CXX11_TLS)

check_cxx_source_compiles ("
__attribute__((thread)) int tls;
int main() { }
" HAVE_CYGWIN_TLS)

if (WITH_TLS)
if (HAVE_CYGWIN_TLS)
set (GLOG_THREAD_LOCAL_STORAGE "__attribute__((thread))")
# Cygwin does not support the thread attribute. Don't bother.
if (HAVE_GCC_TLS)
set (GLOG_THREAD_LOCAL_STORAGE "__thread")
elseif (HAVE_MSVC_TLS)
set (GLOG_THREAD_LOCAL_STORAGE "__declspec(thread)")
elseif (HAVE_CXX11_TLS)
set (GLOG_THREAD_LOCAL_STORAGE thread_local)
endif (HAVE_CYGWIN_TLS)
endif (HAVE_GCC_TLS)
endif (WITH_TLS)

set (_PC_FIELDS
Expand Down
6 changes: 0 additions & 6 deletions src/glog/logging.h.in
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1114,11 +1114,6 @@ class GOOGLE_GLOG_DLL_DECL LogStreamBuf : public std::streambuf {
setp(buf, buf + len - 2);
}

// Resets the buffer. Useful if we reuse it by means of TLS.
void reset() {
setp(pbase(), epptr());
}

// This effectively ignores overflow.
virtual int_type overflow(int_type ch) {
return ch;
Expand Down Expand Up @@ -1181,7 +1176,6 @@ public:
size_t pcount() const { return streambuf_.pcount(); }
char* pbase() const { return streambuf_.pbase(); }
char* str() const { return pbase(); }
void reset() { streambuf_.reset(); }

private:
LogStream(const LogStream&);
Expand Down
22 changes: 10 additions & 12 deletions src/logging.cc
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -331,7 +331,6 @@ const size_t LogMessage::kMaxLogMessageLen = 30000;

struct LogMessage::LogMessageData {
LogMessageData();
void reset();

int preserved_errno_; // preserved errno
// Buffer space; contains complete message text.
Expand Down Expand Up @@ -1151,17 +1150,13 @@ static LogMessage::LogMessageData fatal_msg_data_shared;
// LogMessageData object exists (in this case glog makes zero heap memory
// allocations).
static GLOG_THREAD_LOCAL_STORAGE bool thread_data_available = true;
static GLOG_THREAD_LOCAL_STORAGE LogMessage::LogMessageData thread_msg_data;
static GLOG_THREAD_LOCAL_STORAGE char thread_msg_data[sizeof(LogMessage::LogMessageData)];
#endif // defined(GLOG_THREAD_LOCAL_STORAGE)

LogMessage::LogMessageData::LogMessageData()
: stream_(message_text_, LogMessage::kMaxLogMessageLen, 0) {
}

void LogMessage::LogMessageData::reset() {
stream_.reset();
}

LogMessage::LogMessage(const char* file, int line, LogSeverity severity,
int ctr, void (LogMessage::*send_method)())
: allocated_(NULL) {
Expand Down Expand Up @@ -1218,10 +1213,7 @@ void LogMessage::Init(const char* file,
// No need for locking, because this is thread local.
if (thread_data_available) {
thread_data_available = false;
data_ = &thread_msg_data;
// Make sure to clear log data since it may have been used and filled with
// data. We do not want to append the new message to the previous one.
data_->reset();
data_ = new (&thread_msg_data) LogMessageData;
} else {
allocated_ = new LogMessageData();
data_ = allocated_;
Expand Down Expand Up @@ -1299,10 +1291,16 @@ void LogMessage::Init(const char* file,
LogMessage::~LogMessage() {
Flush();
#ifdef GLOG_THREAD_LOCAL_STORAGE
if (data_ == &thread_msg_data)
if (data_ == static_cast<void*>(thread_msg_data)) {
data_->~LogMessageData();
thread_data_available = true;
#endif // defined(GLOG_THREAD_LOCAL_STORAGE)
}
else {
delete allocated_;
}
#else // !defined(GLOG_THREAD_LOCAL_STORAGE)
delete allocated_;
#endif // defined(GLOG_THREAD_LOCAL_STORAGE)
}

int LogMessage::preserved_errno() const {
Expand Down
7 changes: 6 additions & 1 deletion src/logging_unittest.cc
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -272,7 +272,12 @@ void TestLogging(bool check_counts) {
LOG(ERROR) << string("foo") << ' '<< j << ' ' << setw(10) << j << " "
<< setw(1) << hex << j;

LOG(ERROR) << (&LOG(ERROR) && 0) << " nested LOG";
{
google::LogMessage outer(__FILE__, __LINE__, google::ERROR);
outer.stream() << "outer";

LOG(ERROR) << "inner";
}

LogMessage("foo", LogMessage::kNoLogPrefix, GLOG_INFO).stream() << "no prefix";

Expand Down
4 changes: 2 additions & 2 deletions src/logging_unittest.err
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -74,8 +74,8 @@ WDATE TIME__ THREADID logging_unittest.cc:LINE] log_if this
IDATE TIME__ THREADID logging_unittest.cc:LINE] array
IDATE TIME__ THREADID logging_unittest.cc:LINE] const array
EDATE TIME__ THREADID logging_unittest.cc:LINE] foo 1000 0000001000 3e8
EDATE TIME__ THREADID logging_unittest.cc:LINE] 0 nested LOG
EDATE TIME__ THREADID logging_unittest.cc:LINE]
EDATE TIME__ THREADID logging_unittest.cc:LINE] inner
EDATE TIME__ THREADID logging_unittest.cc:LINE] outer
no prefix
IDATE TIME__ THREADID logging_unittest.cc:LINE] RAW: foo bar 10 3.400000
WDATE TIME__ THREADID logging_unittest.cc:LINE] RAW: array
Expand Down