perf_hooks: fix timing

Fixes: https://github.com/nodejs/node/issues/17892
Fixes: https://github.com/nodejs/node/issues/17893
Fixes: https://github.com/nodejs/node/issues/18992

PR-URL: https://github.com/nodejs/node/pull/18993
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>

1 files changed, 35 insertions, 0 deletions

diff --git a/src/node_perf.cc b/src/node_perf.cc
index db4eff5353..bf9746e429 100644
--- a/src/node_perf.cc
+++ b/src/node_perf.cc
@@ -3,6 +3,10 @@
 
 #include <vector>
 
+#ifdef __POSIX__
+#include <sys/time.h>  // gettimeofday
+#endif
+
 namespace node {
 namespace performance {
 
@@ -21,13 +25,38 @@ using v8::Object;
 using v8::String;
 using v8::Value;
 
+// Microseconds in a second, as a float.
+#define MICROS_PER_SEC 1e6
+// Microseconds in a millisecond, as a float.
+#define MICROS_PER_MILLIS 1e3
+
+// https://w3c.github.io/hr-time/#dfn-time-origin
 const uint64_t timeOrigin = PERFORMANCE_NOW();
+// https://w3c.github.io/hr-time/#dfn-time-origin-timestamp
+const double timeOriginTimestamp = GetCurrentTimeInMicroseconds();
 uint64_t performance_node_start;
 uint64_t performance_v8_start;
 
 uint64_t performance_last_gc_start_mark_ = 0;
 v8::GCType performance_last_gc_type_ = v8::GCType::kGCTypeAll;
 
+double GetCurrentTimeInMicroseconds() {
+#ifdef _WIN32
+// The difference between the Unix Epoch and the Windows Epoch in 100-ns ticks.
+#define TICKS_TO_UNIX_EPOCH 116444736000000000LL
+  FILETIME ft;
+  GetSystemTimeAsFileTime(&ft);
+  uint64_t filetime_int = static_cast<uint64_t>(ft.dwHighDateTime) << 32 |
+                          ft.dwLowDateTime;
+  // FILETIME is measured in terms of 100 ns. Convert that to 1 us (1000 ns).
+  return (filetime_int - TICKS_TO_UNIX_EPOCH) / 10.;
+#else
+  struct timeval tp;
+  gettimeofday(&tp, nullptr);
+  return MICROS_PER_SEC * tp.tv_sec + tp.tv_usec;
+#endif
+}
+
 // Initialize the performance entry object properties
 inline void InitObject(const PerformanceEntry& entry, Local<Object> obj) {
   Environment* env = entry.env();
@@ -384,6 +413,12 @@ void Init(Local<Object> target,
                             v8::Number::New(isolate, timeOrigin / 1e6),
                             attr).ToChecked();
 
+  target->DefineOwnProperty(
+      context,
+      FIXED_ONE_BYTE_STRING(isolate, "timeOriginTimestamp"),
+      v8::Number::New(isolate, timeOriginTimestamp / MICROS_PER_MILLIS),
+      attr).ToChecked();
+
   target->DefineOwnProperty(context,
                             env->constants_string(),
                             constants,