Add time getters to the process interface for requesting the elapsed

wall time, user time, and system time since a process started.

For walltime, we currently use TimeValue's interface and a global
initializer to compute a close approximation of total process runtime.

For user time, this adds support for an somewhat more precise timing
mechanism -- clock_gettime with the CLOCK_PROCESS_CPUTIME_ID clock
selected.

For system time, we have to do a full getrusage call to extract the
system time from the OS. This is expensive but unavoidable.

In passing, clean up the implementation of the old APIs and fix some
latent bugs in the Windows code. This might have manifested on Windows
ARM systems or other systems with strange 64-bit integer behavior.

The old API for this both user time and system time simultaneously from
a single getrusage call. While this results in fewer system calls, it
also results in a lower precision user time and if only user time is
desired, it introduces a higher overhead. It may be worthwhile to switch
some of the pass timers to not track system time and directly track user
and wall time. The old API also tracked walltime in a confusing way --
it just set it to the current walltime rather than providing any measure
of wall time since the process started the way buth user and system time
are tracked. The new API is more consistent here.

The plan is to eventually implement these methods for a *child* process
by using the wait3(2) system call to populate an rusage struct
representing the whole subprocess execution. That way, after waiting on
a child process its stats will become accurate and cheap to query.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171551 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/autoconf/configure.ac b/autoconf/configure.ac
index c5ac14999fc8eedbd98f80b167877da6ed0ebdc2..fdda3f956717d6f5e3434332af0b1aedef5fd5d2 100644 (file)
--- a/autoconf/configure.ac
+++ b/autoconf/configure.ac
@@ -1250,6 +1250,10 @@ AC_SEARCH_LIBS(dlopen,dl,AC_DEFINE([HAVE_DLOPEN],[1],
                [Define if dlopen() is available on this platform.]),
                AC_MSG_WARN([dlopen() not found - disabling plugin support]))
 
+dnl clock_gettime() is required for modern timing support.
+AC_SEARCH_LIBS(clock_gettime,rt,[],
+               AC_MSG_ERROR([clock_gettime not found and is required for modern POSIX timing uspport]))
+
 dnl libffi is optional; used to call external functions from the interpreter
 if test "$llvm_cv_enable_libffi" = "yes" ; then
   AC_SEARCH_LIBS(ffi_call,ffi,AC_DEFINE([HAVE_FFI_CALL],[1],

diff --git a/cmake/config-ix.cmake b/cmake/config-ix.cmake
index 274de31c9efae3d421e7d5bd5b9212af2ebacbce..c625b871e4c3fa1feeef7ddb608275e977324269 100755 (executable)
--- a/cmake/config-ix.cmake
+++ b/cmake/config-ix.cmake
@@ -99,6 +99,7 @@ if( NOT PURE_WINDOWS )
     endif()
   endif()
   check_library_exists(dl dlopen "" HAVE_LIBDL)
+  check_library_exists(rt clock_gettime "" HAVE_LIBRT)
 endif()
 
 # function checks

diff --git a/cmake/modules/LLVM-Config.cmake b/cmake/modules/LLVM-Config.cmake
index 574335c49d0e4f514fa3ad07ded4b041e168a168..163401c857c54b9258379097089085915906de6d 100755 (executable)
--- a/cmake/modules/LLVM-Config.cmake
+++ b/cmake/modules/LLVM-Config.cmake
@@ -4,11 +4,14 @@ function(get_system_libs return_var)
     if( MINGW )
       set(system_libs ${system_libs} imagehlp psapi)
     elseif( CMAKE_HOST_UNIX )
+      if( HAVE_LIBRT )
+        set(system_libs ${system_libs} rt)
+      endif()
       if( HAVE_LIBDL )
-       set(system_libs ${system_libs} ${CMAKE_DL_LIBS})
+        set(system_libs ${system_libs} ${CMAKE_DL_LIBS})
       endif()
       if( LLVM_ENABLE_THREADS AND HAVE_LIBPTHREAD )
-       set(system_libs ${system_libs} pthread)
+        set(system_libs ${system_libs} pthread)
       endif()
     endif( MINGW )
   endif( NOT MSVC )

diff --git a/configure b/configure
index e466dd67ca2a8e074fa9ab0f60884551f45d72ed..8e06154b98c4b1aa4c1aaa9c72f292c15d48b900 100755 (executable)
--- a/configure
+++ b/configure
@@ -12517,6 +12517,110 @@ echo "$as_me: WARNING: dlopen() not found - disabling plugin support" >&2;}
 fi
 
 
+{ echo "$as_me:$LINENO: checking for library containing clock_gettime" >&5
+echo $ECHO_N "checking for library containing clock_gettime... $ECHO_C" >&6; }
+if test "${ac_cv_search_clock_gettime+set}" = set; then
+  echo $ECHO_N "(cached) $ECHO_C" >&6
+else
+  ac_func_search_save_LIBS=$LIBS
+cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char clock_gettime ();
+int
+main ()
+{
+return clock_gettime ();
+  ;
+  return 0;
+}
+_ACEOF
+for ac_lib in '' rt; do
+  if test -z "$ac_lib"; then
+    ac_res="none required"
+  else
+    ac_res=-l$ac_lib
+    LIBS="-l$ac_lib  $ac_func_search_save_LIBS"
+  fi
+  rm -f conftest.$ac_objext conftest$ac_exeext
+if { (ac_try="$ac_link"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_link") 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } &&
+        { ac_try='test -z "$ac_c_werror_flag" || test ! -s conftest.err'
+  { (case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_try") 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; } &&
+        { ac_try='test -s conftest$ac_exeext'
+  { (case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_try") 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+  ac_cv_search_clock_gettime=$ac_res
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+
+fi
+
+rm -f core conftest.err conftest.$ac_objext \
+      conftest$ac_exeext
+  if test "${ac_cv_search_clock_gettime+set}" = set; then
+  break
+fi
+done
+if test "${ac_cv_search_clock_gettime+set}" = set; then
+  :
+else
+  ac_cv_search_clock_gettime=no
+fi
+rm conftest.$ac_ext
+LIBS=$ac_func_search_save_LIBS
+fi
+{ echo "$as_me:$LINENO: result: $ac_cv_search_clock_gettime" >&5
+echo "${ECHO_T}$ac_cv_search_clock_gettime" >&6; }
+ac_res=$ac_cv_search_clock_gettime
+if test "$ac_res" != no; then
+  test "$ac_res" = "none required" || LIBS="$ac_res $LIBS"
+
+else
+  { { echo "$as_me:$LINENO: error: clock_gettime not found and is required for modern POSIX timing uspport" >&5
+echo "$as_me: error: clock_gettime not found and is required for modern POSIX timing uspport" >&2;}
+   { (exit 1); exit 1; }; }
+fi
+
+
 if test "$llvm_cv_enable_libffi" = "yes" ; then
   { echo "$as_me:$LINENO: checking for library containing ffi_call" >&5
 echo $ECHO_N "checking for library containing ffi_call... $ECHO_C" >&6; }

diff --git a/include/llvm/Support/Process.h b/include/llvm/Support/Process.h
index f149a4e058b15df964f2b65c5b011c9a8f601462..ea8da6d4c5b5fe830ba77c307756a17fe2a27343 100644 (file)
--- a/include/llvm/Support/Process.h
+++ b/include/llvm/Support/Process.h
@@ -64,6 +64,23 @@ public:
   /// \brief Get the operating system specific identifier for this process.
   virtual id_type get_id() = 0;
 
+  /// \brief Get the user time consumed by this process.
+  ///
+  /// Note that this is often an approximation and may be zero on platforms
+  /// where we don't have good support for the functionality.
+  virtual TimeValue get_user_time() const = 0;
+
+  /// \brief Get the system time consumed by this process.
+  ///
+  /// Note that this is often an approximation and may be zero on platforms
+  /// where we don't have good support for the functionality.
+  virtual TimeValue get_system_time() const = 0;
+
+  /// \brief Get the wall time consumed by this process.
+  ///
+  /// Note that this is often an approximation and may be zero on platforms
+  /// where we don't have good support for the functionality.
+  virtual TimeValue get_wall_time() const = 0;
 
   /// \name Static factory routines for processes.
   /// @{
@@ -88,6 +105,9 @@ class self_process : public process {
 
 public:
   virtual id_type get_id();
+  virtual TimeValue get_user_time() const;
+  virtual TimeValue get_system_time() const;
+  virtual TimeValue get_wall_time() const;
 
   /// \name Process configuration (sysconf on POSIX)
   /// @{

diff --git a/lib/Support/Process.cpp b/lib/Support/Process.cpp
index 64a1fa237ee016c1e02a5df31858321a4ae91e05..2c0d37bb32992720ec37892e1415abc4272f9167 100644 (file)
--- a/lib/Support/Process.cpp
+++ b/lib/Support/Process.cpp
@@ -50,6 +50,31 @@ self_process::~self_process() {
   llvm_unreachable("This destructor must never be executed!");
 }
 
+/// \brief A helper function to compute the elapsed wall-time since the program
+/// started.
+///
+/// Note that this routine actually computes the elapsed wall time since the
+/// first time it was called. However, we arrange to have it called during the
+/// startup of the process to get approximately correct results.
+static TimeValue getElapsedWallTime() {
+  static TimeValue &StartTime = *new TimeValue(TimeValue::now());
+  return TimeValue::now() - StartTime;
+}
+
+/// \brief A special global variable to ensure we call \c getElapsedWallTime
+/// during global initialization of the program.
+///
+/// Note that this variable is never referenced elsewhere. Doing so could
+/// create race conditions during program startup or shutdown.
+static volatile TimeValue DummyTimeValue = getElapsedWallTime();
+
+// Implement this routine by using the static helpers above. They're already
+// portable.
+TimeValue self_process::get_wall_time() const {
+  return getElapsedWallTime();
+}
+
+
 #if defined(_MSC_VER)
 #pragma warning(pop)
 #endif

diff --git a/lib/Support/Unix/Process.inc b/lib/Support/Unix/Process.inc
index 9ad6272bab48b3f3239b9feb08e54c58dbe25942..a525538f78b568ced362b68d88280d0bb9967a17 100644 (file)
--- a/lib/Support/Unix/Process.inc
+++ b/lib/Support/Unix/Process.inc
@@ -49,6 +49,43 @@ process::id_type self_process::get_id() {
   return getpid();
 }
 
+static std::pair<TimeValue, TimeValue> getRUsageTimes() {
+#if defined(HAVE_GETRUSAGE)
+  struct rusage RU;
+  ::getrusage(RUSAGE_SELF, &RU);
+  return std::make_pair(
+      TimeValue(
+          static_cast<TimeValue::SecondsType>(RU.ru_utime.tv_sec),
+          static_cast<TimeValue::NanoSecondsType>(
+              RU.ru_utime.tv_usec * TimeValue::NANOSECONDS_PER_MICROSECOND)),
+      TimeValue(
+          static_cast<TimeValue::SecondsType>(RU.ru_stime.tv_sec),
+          static_cast<TimeValue::NanoSecondsType>(
+              RU.ru_stime.tv_usec * TimeValue::NANOSECONDS_PER_MICROSECOND)));
+#else
+#warning Cannot get usage times on this platform
+  return std::make_pair(TimeValue(), TimeValue());
+#endif
+}
+
+TimeValue self_process::get_user_time() const {
+#ifdef _POSIX_CPUTIME
+  // Try to get a high resolution CPU timer.
+  struct timespec TS;
+  if (::clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &TS) == 0)
+    return TimeValue(static_cast<TimeValue::SecondsType>(TS.tv_sec),
+                     static_cast<TimeValue::NanoSecondsType>(TS.tv_nsec));
+#endif
+
+  // Otherwise fall back to rusage based timing.
+  return getRUsageTimes().first;
+}
+
+TimeValue self_process::get_system_time() const {
+  // We can only collect system time by inspecting the results of getrusage.
+  return getRUsageTimes().second;
+}
+
 static unsigned getPageSize() {
 #if defined(__CYGWIN__)
   // On Cygwin, getpagesize() returns 64k but the page size for the purposes of
@@ -95,29 +132,10 @@ size_t Process::GetMallocUsage() {
 #endif
 }
 
-void
-Process::GetTimeUsage(TimeValue& elapsed, TimeValue& user_time,
-                      TimeValue& sys_time)
-{
+void Process::GetTimeUsage(TimeValue &elapsed, TimeValue &user_time,
+                           TimeValue &sys_time) {
   elapsed = TimeValue::now();
-#if defined(HAVE_GETRUSAGE)
-  struct rusage usage;
-  ::getrusage(RUSAGE_SELF, &usage);
-  user_time = TimeValue(
-    static_cast<TimeValue::SecondsType>( usage.ru_utime.tv_sec ),
-    static_cast<TimeValue::NanoSecondsType>( usage.ru_utime.tv_usec *
-      TimeValue::NANOSECONDS_PER_MICROSECOND ) );
-  sys_time = TimeValue(
-    static_cast<TimeValue::SecondsType>( usage.ru_stime.tv_sec ),
-    static_cast<TimeValue::NanoSecondsType>( usage.ru_stime.tv_usec *
-      TimeValue::NANOSECONDS_PER_MICROSECOND ) );
-#else
-#warning Cannot get usage times on this platform
-  user_time.seconds(0);
-  user_time.microseconds(0);
-  sys_time.seconds(0);
-  sys_time.microseconds(0);
-#endif
+  llvm::tie(user_time, sys_time) = getRUsageTimes();
 }
 
 int Process::GetCurrentUserId() {

diff --git a/lib/Support/Windows/Process.inc b/lib/Support/Windows/Process.inc
index 9eb611be8707b97f58b7d37a01b4b0c24a1096a2..789ae7ddcea7fadd9fc65f6924539fbd067a60d5 100644 (file)
--- a/lib/Support/Windows/Process.inc
+++ b/lib/Support/Windows/Process.inc
@@ -43,6 +43,36 @@ process::id_type self_process::get_id() {
   return GetCurrentProcess();
 }
 
+static TimeValue getTimeValueFromFILETIME(FILETIME Time) {
+  ULARGE_INTEGER TimeInteger;
+  TimeInteger.LowPart = Time.dwLowDateTime;
+  TimeInteger.HighPart = Time.dwHighDateTime;
+
+  // FILETIME's are # of 100 nanosecond ticks (1/10th of a microsecond)
+  return TimeValue(
+      static_cast<TimeValue::SecondsType>(TimeInteger.QuadPart / 10000000),
+      static_cast<TimeValue::NanoSecondsType>(
+          (TimeInteger.QuadPart % 10000000) * 100));
+}
+
+TimeValue self_process::get_user_time() const {
+  FILETIME ProcCreate, ProcExit, KernelTime, UserTime;
+  if (GetProcessTimes(GetCurrentProcess(), &ProcCreate, &ProcExit, &KernelTime,
+                      &UserTime) == 0)
+    return TimeValue();
+
+  return getTimeValueFromFILETIME(UserTime);
+}
+
+TimeValue self_process::get_system_time() const {
+  FILETIME ProcCreate, ProcExit, KernelTime, UserTime;
+  if (GetProcessTimes(GetCurrentProcess(), &ProcCreate, &ProcExit, &KernelTime,
+                      &UserTime) == 0)
+    return TimeValue();
+
+  return getTimeValueFromFILETIME(KernelTime);
+}
+
 // This function retrieves the page size using GetSystemInfo and is present
 // solely so it can be called once to initialize the self_process member below.
 static unsigned getPageSize() {
@@ -76,22 +106,17 @@ Process::GetMallocUsage()
   return size;
 }
 
-void
-Process::GetTimeUsage(
-  TimeValue& elapsed, TimeValue& user_time, TimeValue& sys_time)
-{
+void Process::GetTimeUsage(TimeValue &elapsed, TimeValue &user_time,
+                           TimeValue &sys_time) {
   elapsed = TimeValue::now();
 
-  uint64_t ProcCreate, ProcExit, KernelTime, UserTime;
-  GetProcessTimes(GetCurrentProcess(), (FILETIME*)&ProcCreate,
-                  (FILETIME*)&ProcExit, (FILETIME*)&KernelTime,
-                  (FILETIME*)&UserTime);
+  FILETIME ProcCreate, ProcExit, KernelTime, UserTime;
+  if (GetProcessTimes(GetCurrentProcess(), &ProcCreate, &ProcExit, &KernelTime,
+                      &UserTime) == 0)
+    return;
 
-  // FILETIME's are # of 100 nanosecond ticks (1/10th of a microsecond)
-  user_time.seconds( UserTime / 10000000 );
-  user_time.nanoseconds( unsigned(UserTime % 10000000) * 100 );
-  sys_time.seconds( KernelTime / 10000000 );
-  sys_time.nanoseconds( unsigned(KernelTime % 10000000) * 100 );
+  user_time = getTimeValueFromFILETIME(UserTime);
+  sys_time = getTimeValueFromFILETIME(SystemTime);
 }
 
 int Process::GetCurrentUserId()

diff --git a/unittests/Support/ProcessTest.cpp b/unittests/Support/ProcessTest.cpp
index 58a7c4acaaa18a3fffda2ec0e2f551b736c9fab7..e57c0e6eaf81ab664e078700b28adfb1f3661b37 100644 (file)
--- a/unittests/Support/ProcessTest.cpp
+++ b/unittests/Support/ProcessTest.cpp
@@ -30,6 +30,13 @@ TEST(ProcessTest, SelfProcess) {
 #endif
 
   EXPECT_LT(1u, process::get_self()->page_size());
+
+  EXPECT_LT(TimeValue::MinTime, process::get_self()->get_user_time());
+  EXPECT_GT(TimeValue::MaxTime, process::get_self()->get_user_time());
+  EXPECT_LT(TimeValue::MinTime, process::get_self()->get_system_time());
+  EXPECT_GT(TimeValue::MaxTime, process::get_self()->get_system_time());
+  EXPECT_LT(TimeValue::MinTime, process::get_self()->get_wall_time());
+  EXPECT_GT(TimeValue::MaxTime, process::get_self()->get_wall_time());
 }
 
 } // end anonymous namespace