report: add cpu info to report output

The report shows CPU consumption %, but without the number of CPU cores,
a consumer cannot tell if the percent (given across all cores) is
actually problematic. E.g., 100% on one CPU is a problem, but 100% on
four CPUs is not necessarily.

This change adds CPU information (similar to `os.cpus()`) to the report
output. Extra info besides the count is also provided as to avoid future
breaking changes in the eventuality that someone needs it; changing the
datatype of `header.cpus` would be breaking.

PR-URL: #28188
Refs: nodejs/diagnostics#307
Reviewed-By: Sam Roberts <vieuxtech@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

doc/api/report.md

@@ -62,6 +62,26 @@ is provided below for reference.
     "osRelease": "3.10.0-862.el7.x86_64",
     "osVersion": "#1 SMP Wed Mar 21 18:14:51 EDT 2018",
     "osMachine": "x86_64",
+    "osCpus": [
+      {
+        "model": "Intel(R) Core(TM) i7-6820HQ CPU @ 2.70GHz",
+        "speed": 2700,
+        "user": 88902660,
+        "nice": 0,
+        "sys": 50902570,
+        "idle": 241732220,
+        "irq": 0
+      },
+      {
+        "model": "Intel(R) Core(TM) i7-6820HQ CPU @ 2.70GHz",
+        "speed": 2700,
+        "user": 88902660,
+        "nice": 0,
+        "sys": 50902570,
+        "idle": 241732220,
+        "irq": 0
+      }
+    ],
     "host": "test_machine"
   },
   "javascriptStack": {

src/node_report.cc

@@ -65,6 +65,7 @@ static void PrintSystemInformation(JSONWriter* writer);
 static void PrintLoadedLibraries(JSONWriter* writer);
 static void PrintComponentVersions(JSONWriter* writer);
 static void PrintRelease(JSONWriter* writer);
+static void PrintCpuInfo(JSONWriter* writer);
 
 // External function to trigger a report, writing to file.
 // The 'name' parameter is in/out: an input filename is used
@@ -315,13 +316,37 @@ static void PrintVersionInformation(JSONWriter* writer) {
     writer->json_keyvalue("osMachine", os_info.machine);
   }
 
+  PrintCpuInfo(writer);
+
   char host[UV_MAXHOSTNAMESIZE];
   size_t host_size = sizeof(host);
 
   if (uv_os_gethostname(host, &host_size) == 0)
     writer->json_keyvalue("host", host);
 }
 
+// Report CPU info
+static void PrintCpuInfo(JSONWriter* writer) {
+  uv_cpu_info_t* cpu_info;
+  int count;
+  if (uv_cpu_info(&cpu_info, &count) == 0) {
+    writer->json_arraystart("cpus");
+    for (int i = 0; i < count; i++) {
+      writer->json_start();
+      writer->json_keyvalue("model", cpu_info->model);
+      writer->json_keyvalue("speed", cpu_info->speed);
+      writer->json_keyvalue("user", cpu_info->cpu_times.user);
+      writer->json_keyvalue("nice", cpu_info->cpu_times.nice);
+      writer->json_keyvalue("sys", cpu_info->cpu_times.sys);
+      writer->json_keyvalue("idle", cpu_info->cpu_times.idle);
+      writer->json_keyvalue("irq", cpu_info->cpu_times.irq);
+      writer->json_end();
+    }
+    writer->json_arrayend();
+    uv_free_cpu_info(cpu_info, count);
+  }
+}
+
 // Report the JavaScript stack.
 static void PrintJavaScriptStack(JSONWriter* writer,
                                  Isolate* isolate,

test/common/report.js

@@ -62,8 +62,8 @@ function _validateContent(data) {
                         'dumpEventTimeStamp', 'processId', 'commandLine',
                         'nodejsVersion', 'wordSize', 'arch', 'platform',
                         'componentVersions', 'release', 'osName', 'osRelease',
-                        'osVersion', 'osMachine', 'host', 'glibcVersionRuntime',
-                        'glibcVersionCompiler', 'cwd'];
+                        'osVersion', 'osMachine', 'cpus', 'host',
+                        'glibcVersionRuntime', 'glibcVersionCompiler', 'cwd'];
   checkForUnknownFields(header, headerFields);
   assert.strictEqual(typeof header.event, 'string');
   assert.strictEqual(typeof header.trigger, 'string');
@@ -87,6 +87,16 @@ function _validateContent(data) {
   assert.strictEqual(header.osRelease, os.release());
   assert.strictEqual(typeof header.osVersion, 'string');
   assert.strictEqual(typeof header.osMachine, 'string');
+  assert(Array.isArray(header.cpus));
+  header.cpus.forEach((cpu) => {
+    assert.strictEqual(typeof cpu.model, 'string');
+    assert.strictEqual(typeof cpu.speed, 'number');
+    assert.strictEqual(typeof cpu.user, 'number');
+    assert.strictEqual(typeof cpu.nice, 'number');
+    assert.strictEqual(typeof cpu.sys, 'number');
+    assert.strictEqual(typeof cpu.idle, 'number');
+    assert.strictEqual(typeof cpu.irq, 'number');
+  });
   assert.strictEqual(header.host, os.hostname());
 
   // Verify the format of the javascriptStack section.