a.txt

Values are time in nanoseconds

pre-monotonic change

  ready                                             
           value  ------------- Distribution ------------- count    
         8388608 |                                         0        
        16777216 |@@@                                      188      
        33554432 |@@@@@@@@@@                               624      
        67108864 |@@@@@@                                   354      
       134217728 |@@@@@@                                   389      
       268435456 |@@@@@@@@                                 485      
       536870912 |@@@@@                                    336      
      1073741824 |@@                                       104      
      2147483648 |                                         2        
      4294967296 |                                         0        

Worst start up time -- 2 seconds, best 16ms

  init                                              
           value  ------------- Distribution ------------- count    
         1048576 |                                         0        
         2097152 |                                         6        
         4194304 |@@@@@@@@                                 513      
         8388608 |@@@@@@@@@@                               597      
        16777216 |@@@@@                                    300      
        33554432 |@@@@                                     227      
        67108864 |@@@@                                     241      
       134217728 |@@@                                      189      
       268435456 |@@@                                      200      
       536870912 |@@@                                      170      
      1073741824 |@                                        61       
      2147483648 |                                         0        

worst time 1 second, best time 4ms

after monotonic change

  ready
           value  ------------- Distribution ------------- count
         8388608 |                                         0
        16777216 |@@@@@@@@                                 513
        33554432 |@@@@@@                                   386
        67108864 |@@@@@                                    331
       134217728 |@@@@@@@                                  433
       268435456 |@@@@@@                                   379
       536870912 |@@@@@                                    332
      1073741824 |@                                        72
      2147483648 |                                         12
      4294967296 |                                         0

worst ready time 2 seconds, best ready time 16ms

  init
           value  ------------- Distribution ------------- count
           65536 |                                         0
          131072 |@                                        52
          262144 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@           1866
          524288 |@                                        59
         1048576 |                                         20
         2097152 |                                         15
         4194304 |@                                        65
         8388608 |@                                        60
        16777216 |@                                        33
        33554432 |@                                        40
        67108864 |@                                        47
       134217728 |@                                        47
       268435456 |@                                        90
       536870912 |@@                                       105
      1073741824 |                                         13
      2147483648 |                                         3
      4294967296 |                                         0

worst init 2 seconds, best init 131 microseconds

faster-init.diff

diff --git a/node.gyp b/node.gyp
index f6586c4..ad90b83 100644
--- a/node.gyp
+++ b/node.gyp
@@ -428,7 +428,8 @@
               'action_name': 'node_dtrace_provider_o',
               'inputs': [
                 'src/node_provider.d',
-                '<(OBJ_DIR)/node/src/node_dtrace.o'
+                '<(OBJ_DIR)/node/src/node_dtrace.o',
+                '<(OBJ_DIR)/node/src/node.o'
               ],
               'outputs': [
                 '<(OBJ_DIR)/node/src/node_dtrace_provider.o'
diff --git a/src/node.cc b/src/node.cc
index ac906f0..707627e 100644
--- a/src/node.cc
+++ b/src/node.cc
@@ -82,6 +82,8 @@ typedef int mode_t;
 #include "node_script.h"
 #include "v8_typed_array.h"
 
+#include "node_provider.h"
+
 using namespace v8;
 
 # ifdef __APPLE__
@@ -1714,13 +1716,16 @@ static Handle<Value> Uptime(const Arguments& args) {
   HandleScope scope;
   double uptime;
 
-  uv_err_t err = uv_uptime(&uptime);
+  uv_update_time(uv_default_loop());
+  uptime = uv_now(uv_default_loop());
 
-  if (err.code != UV_OK) {
-    return Undefined();
-  }
+  return scope.Close(Number::New((uptime - prog_start_time) / 1000));
+}
 
-  return scope.Close(Number::New(uptime - prog_start_time));
+static Handle<Value> Ready(const Arguments& args) {
+  NODE_PROC_READY();
+  HandleScope scope;
+  return scope.Close(Undefined());
 }
 
 
@@ -2420,6 +2425,7 @@ Handle<Object> SetupProcessObject(int argc, char *argv[]) {
 
   NODE_SET_METHOD(process, "uptime", Uptime);
   NODE_SET_METHOD(process, "memoryUsage", MemoryUsage);
+  NODE_SET_METHOD(process, "ready", Ready);
 
   NODE_SET_METHOD(process, "binding", Binding);
 
@@ -2893,7 +2899,7 @@ static Handle<Value> DebugEnd(const Arguments& args) {
 
 char** Init(int argc, char *argv[]) {
   // Initialize prog_start_time to get relative uptime.
-  uv_uptime(&prog_start_time);
+  prog_start_time = uv_now(uv_default_loop());
 
   // Make inherited handles noninheritable.
   uv_disable_stdio_inheritance();
@@ -3045,6 +3051,8 @@ static char **copy_argv(int argc, char **argv) {
 }
 
 int Start(int argc, char *argv[]) {
+  NODE_PROC_START();
+
   // Hack aroung with the argv pointer. Used for process.title = "blah".
   argv = uv_setup_args(argc, argv);
 
@@ -3054,7 +3062,9 @@ int Start(int argc, char *argv[]) {
 
   // This needs to run *before* V8::Initialize()
   // Use copy here as to not modify the original argv:
+  NODE_INIT_START();
   Init(argc, argv_copy);
+  NODE_INIT_STOP();
 
   V8::Initialize();
   {
diff --git a/src/node.js b/src/node.js
index b54ff51..807bfca 100644
--- a/src/node.js
+++ b/src/node.js
@@ -57,6 +57,8 @@
 
     startup.resolveArgv0();
 
+    process.ready();
+
     // There are various modes that Node can run in. The most common two
     // are running from a script and running the REPL - but there are a few
     // others like the debugger or running --eval arguments. Here we decide
diff --git a/src/node_provider.d b/src/node_provider.d
index 6f95b03..47fcd5b 100644
--- a/src/node_provider.d
+++ b/src/node_provider.d
@@ -77,6 +77,10 @@ provider node {
 	    int p, int fd) : (node_connection_t *c, string a, int p, int fd);
 	probe gc__start(int t, int f);
 	probe gc__done(int t, int f);
+	probe init__start();
+	probe init__stop();
+	probe proc__start();
+	probe proc__ready();
 };
 
 #pragma D attributes Evolving/Evolving/ISA provider node provider

start.d

#!/usr/sbin/dtrace -s

node*:::proc-start
{
  self->proc_start = timestamp;
}

node*:::proc-ready
/self->proc_start/
{
  @["ready"] = quantize(timestamp - self->proc_start);
  self->proc_start = 0;
}

node*:::init-start
{
  self->init_start = timestamp;
}

node*:::init-stop
/self->init_start/
{
  @["init"] = quantize(timestamp - self->init_start);
  self->init_start = 0;
}

END
{
  printa(@);
}

t.js

var execFile = require('child_process').execFile;
var cluster = require('cluster');

var TOTAL_RUNS = 50;
var CONCURRENCY = 50;

function doit(id, count) {
  if (count > TOTAL_RUNS)
    process.exit(0);

  //console.log('launching', id, count);

  var child = execFile(process.execPath, ['-e', '']);
  child.on('close', function() {
    doit(id, ++count);
  });
}

if (cluster.isMaster) {
  for (var i = 0; i < CONCURRENCY; i++)
    cluster.fork();
} else {
  doit(1, 1);
}