os: improve cpus() performance

PR-URL: https://github.com/nodejs/node/pull/11564
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Jackson Tian <shyvo1987@gmail.com>

benchmark/os/cpus.js

@@ -0,0 +1,17 @@
+'use strict';
+
+const common = require('../common.js');
+const cpus = require('os').cpus;
+
+const bench = common.createBenchmark(main, {
+  n: [3e4]
+});
+
+function main(conf) {
+  const n = +conf.n;
+
+  bench.start();
+  for (var i = 0; i < n; ++i)
+    cpus();
+  bench.end(n);
+}

lib/os.js

@@ -1,7 +1,9 @@
 'use strict';
 
 const binding = process.binding('os');
+const getCPUs = binding.getCPUs;
 const getLoadAvg = binding.getLoadAvg;
+const pushValToArrayMax = process.binding('util').pushValToArrayMax;
 const constants = process.binding('constants').os;
 const internalUtil = require('internal/util');
 const isWindows = process.platform === 'win32';
@@ -10,7 +12,6 @@ exports.hostname = binding.getHostname;
 exports.uptime = binding.getUptime;
 exports.freemem = binding.getFreeMem;
 exports.totalmem = binding.getTotalMem;
-exports.cpus = binding.getCPUs;
 exports.type = binding.getOSType;
 exports.release = binding.getOSRelease;
 exports.networkInterfaces = binding.getInterfaceAddresses;
@@ -23,6 +24,26 @@ exports.loadavg = function loadavg() {
   return [avgValues[0], avgValues[1], avgValues[2]];
 };
 
+const cpuValues = new Float64Array(6 * pushValToArrayMax);
+function addCPUInfo() {
+  for (var i = 0, c = 0; i < arguments.length; ++i, c += 6) {
+    this[this.length] = {
+      model: arguments[i],
+      speed: cpuValues[c],
+      times: {
+        user: cpuValues[c + 1],
+        nice: cpuValues[c + 2],
+        sys: cpuValues[c + 3],
+        idle: cpuValues[c + 4],
+        irq: cpuValues[c + 5]
+      }
+    };
+  }
+}
+exports.cpus = function cpus() {
+  return getCPUs(addCPUInfo, cpuValues, []);
+};
+
 Object.defineProperty(exports, 'constants', {
   configurable: false,
   enumerable: true,

src/node_os.cc

@@ -32,6 +32,7 @@ using v8::ArrayBuffer;
 using v8::Boolean;
 using v8::Context;
 using v8::Float64Array;
+using v8::Function;
 using v8::FunctionCallbackInfo;
 using v8::Integer;
 using v8::Local;
@@ -122,36 +123,47 @@ static void GetOSRelease(const FunctionCallbackInfo<Value>& args) {
 static void GetCPUInfo(const FunctionCallbackInfo<Value>& args) {
   Environment* env = Environment::GetCurrent(args);
   uv_cpu_info_t* cpu_infos;
-  int count, i;
+  int count, i, field_idx;
 
   int err = uv_cpu_info(&cpu_infos, &count);
   if (err)
     return;
 
-  Local<Array> cpus = Array::New(env->isolate());
-  for (i = 0; i < count; i++) {
+  CHECK(args[0]->IsFunction());
+  Local<Function> addfn = args[0].As<Function>();
+
+  CHECK(args[1]->IsFloat64Array());
+  Local<Float64Array> array = args[1].As<Float64Array>();
+  CHECK_EQ(array->Length(), 6 * NODE_PUSH_VAL_TO_ARRAY_MAX);
+  Local<ArrayBuffer> ab = array->Buffer();
+  double* fields = static_cast<double*>(ab->GetContents().Data());
+
+  CHECK(args[2]->IsArray());
+  Local<Array> cpus = args[2].As<Array>();
+
+  Local<Value> model_argv[NODE_PUSH_VAL_TO_ARRAY_MAX];
+  int model_idx = 0;
+
+  for (i = 0, field_idx = 0; i < count; i++) {
     uv_cpu_info_t* ci = cpu_infos + i;
 
-    Local<Object> times_info = Object::New(env->isolate());
-    times_info->Set(env->user_string(),
-                    Number::New(env->isolate(), ci->cpu_times.user));
-    times_info->Set(env->nice_string(),
-                    Number::New(env->isolate(), ci->cpu_times.nice));
-    times_info->Set(env->sys_string(),
-                    Number::New(env->isolate(), ci->cpu_times.sys));
-    times_info->Set(env->idle_string(),
-                    Number::New(env->isolate(), ci->cpu_times.idle));
-    times_info->Set(env->irq_string(),
-                    Number::New(env->isolate(), ci->cpu_times.irq));
+    fields[field_idx++] = ci->speed;
+    fields[field_idx++] = ci->cpu_times.user;
+    fields[field_idx++] = ci->cpu_times.nice;
+    fields[field_idx++] = ci->cpu_times.sys;
+    fields[field_idx++] = ci->cpu_times.idle;
+    fields[field_idx++] = ci->cpu_times.irq;
+    model_argv[model_idx++] = OneByteString(env->isolate(), ci->model);
 
-    Local<Object> cpu_info = Object::New(env->isolate());
-    cpu_info->Set(env->model_string(),
-                  OneByteString(env->isolate(), ci->model));
-    cpu_info->Set(env->speed_string(),
-                  Number::New(env->isolate(), ci->speed));
-    cpu_info->Set(env->times_string(), times_info);
+    if (model_idx >= NODE_PUSH_VAL_TO_ARRAY_MAX) {
+      addfn->Call(env->context(), cpus, model_idx, model_argv).ToLocalChecked();
+      model_idx = 0;
+      field_idx = 0;
+    }
+  }
 
-    (*cpus)->Set(i, cpu_info);
+  if (model_idx > 0) {
+    addfn->Call(env->context(), cpus, model_idx, model_argv).ToLocalChecked();
   }
 
   uv_free_cpu_info(cpu_infos, count);

src/node_util.cc

@@ -141,6 +141,12 @@ void Initialize(Local<Object> target,
   }
 #undef V
 
+  target->DefineOwnProperty(
+    env->context(),
+    OneByteString(env->isolate(), "pushValToArrayMax"),
+    Integer::NewFromUnsigned(env->isolate(), NODE_PUSH_VAL_TO_ARRAY_MAX),
+    v8::ReadOnly).FromJust();
+
   env->SetMethod(target, "getHiddenValue", GetHiddenValue);
   env->SetMethod(target, "setHiddenValue", SetHiddenValue);
   env->SetMethod(target, "getProxyDetails", GetProxyDetails);