process: expose uv_rusage on process.resourcesUsage()

As discussed in https://github.com/nodejs/diagnostics/issues/161,
the core should expose important metrics about the runtime, this PR's
goal is to let user get the number of io request made, and lower level
mertrics like the page faults and context switches.

PR-URL: https://github.com/nodejs/node/pull/28018
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>

1 files changed, 33 insertions, 0 deletions

diff --git a/src/node_process_methods.cc b/src/node_process_methods.cc
index b34cbf89b6..3a2c1efd81 100644
--- a/src/node_process_methods.cc
+++ b/src/node_process_methods.cc
@@ -285,6 +285,38 @@ void GetActiveHandles(const FunctionCallbackInfo<Value>& args) {
       Array::New(env->isolate(), handle_v.data(), handle_v.size()));
 }
 
+static void ResourceUsage(const FunctionCallbackInfo<Value>& args) {
+  Environment* env = Environment::GetCurrent(args);
+
+  uv_rusage_t rusage;
+  int err = uv_getrusage(&rusage);
+  if (err)
+    return env->ThrowUVException(err, "uv_getrusage");
+
+  CHECK(args[0]->IsFloat64Array());
+  Local<Float64Array> array = args[0].As<Float64Array>();
+  CHECK_EQ(array->Length(), 16);
+  Local<ArrayBuffer> ab = array->Buffer();
+  double* fields = static_cast<double*>(ab->GetContents().Data());
+
+  fields[0] = MICROS_PER_SEC * rusage.ru_utime.tv_sec + rusage.ru_utime.tv_usec;
+  fields[1] = MICROS_PER_SEC * rusage.ru_stime.tv_sec + rusage.ru_stime.tv_usec;
+  fields[2] = rusage.ru_maxrss;
+  fields[3] = rusage.ru_ixrss;
+  fields[4] = rusage.ru_idrss;
+  fields[5] = rusage.ru_isrss;
+  fields[6] = rusage.ru_minflt;
+  fields[7] = rusage.ru_majflt;
+  fields[8] = rusage.ru_nswap;
+  fields[9] = rusage.ru_inblock;
+  fields[10] = rusage.ru_oublock;
+  fields[11] = rusage.ru_msgsnd;
+  fields[12] = rusage.ru_msgrcv;
+  fields[13] = rusage.ru_nsignals;
+  fields[14] = rusage.ru_nvcsw;
+  fields[15] = rusage.ru_nivcsw;
+}
+
 #ifdef __POSIX__
 static void DebugProcess(const FunctionCallbackInfo<Value>& args) {
   Environment* env = Environment::GetCurrent(args);
@@ -426,6 +458,7 @@ static void InitializeProcessMethods(Local<Object> target,
   env->SetMethod(target, "cpuUsage", CPUUsage);
   env->SetMethod(target, "hrtime", Hrtime);
   env->SetMethod(target, "hrtimeBigInt", HrtimeBigInt);
+  env->SetMethod(target, "resourceUsage", ResourceUsage);
 
   env->SetMethod(target, "_getActiveRequests", GetActiveRequests);
   env->SetMethod(target, "_getActiveHandles", GetActiveHandles);