ev_now patches

0001-Add-process.now.patch

From 314733bb26efdd0a9b6fcb9ea7c1a352bf34f902 Mon Sep 17 00:00:00 2001
From: Jonas Pfenniger <jonas@pfenniger.name>
Date: Fri, 1 Oct 2010 21:29:53 +0200
Subject: [PATCH 1/2] Add process.now()

To avoid making a syscall, process.now() re-uses the timestamp
of the current libev loop, which is provided by ev_now().

The date object of process.now() is cached until ev_now() changes for
performance reasons.

Note that Date.now() also seems to optimize, making only one syscall
if used consecutively.
---
 src/node.cc |   18 ++++++++++++++++++
 1 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/src/node.cc b/src/node.cc
index 004fa99..704bf5e 100644
--- a/src/node.cc
+++ b/src/node.cc
@@ -1541,6 +1541,19 @@ static void ProcessTitleSetter(Local<String> property,
   OS::SetProcessTitle(*title);
 }
 
+static Handle<Value> Now(const Arguments& args) {
+  static ev_tstamp cached_now = 0;
+  static Persistent<Value> cached_date;
+  
+  ev_tstamp now = ev_now(EV_DEFAULT_UC);
+  if (now != cached_now) {
+    cached_date.Dispose();
+    cached_date = Persistent<Value>::New(NODE_UNIXTIME_V8(now));
+    cached_now = now;
+  }
+  
+  return cached_date;
+}
 
 static void Load(int argc, char *argv[]) {
   HandleScope scope;
@@ -1555,6 +1568,11 @@ static void Load(int argc, char *argv[]) {
                        ProcessTitleGetter,
                        ProcessTitleSetter);
 
+  Local<FunctionTemplate> now = FunctionTemplate::New(Now);
+  now->InstanceTemplate()->SetInternalFieldCount(0);
+  now->SetClassName(String::NewSymbol("now"));
+  process->Set(String::NewSymbol("now"), now->GetFunction());
+  
   // process.version
   process->Set(String::NewSymbol("version"), String::New(NODE_VERSION));
 
-- 
1.7.3.1

0002-Add-process.loopTime.patch

From b32625003369d997dcf0bec77cc27284c9e57ab8 Mon Sep 17 00:00:00 2001
From: Jonas Pfenniger <jonas@pfenniger.name>
Date: Mon, 4 Oct 2010 22:10:02 +0200
Subject: [PATCH 2/2] Add process.loopTime

process.loopTime is updated on each iteration of the grand loop with
the Date of ev_now().
---
 src/node.cc |   11 +++++++++++
 1 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/src/node.cc b/src/node.cc
index 704bf5e..0a7d672 100644
--- a/src/node.cc
+++ b/src/node.cc
@@ -68,6 +68,8 @@ static Persistent<String> listeners_symbol;
 static Persistent<String> uncaught_exception_symbol;
 static Persistent<String> emit_symbol;
 
+static Persistent<String> loop_time_symbol;
+
 static int option_end_index = 0;
 static bool use_debug_agent = false;
 static bool debug_wait_connect = false;
@@ -181,6 +183,11 @@ static void Spin(EV_P_ ev_idle *watcher, int revents) {
 }
 
 
+static void UpdateLoopTime(void) {
+  HandleScope scope;
+  process->Set(loop_time_symbol, Local<Value>::New(NODE_UNIXTIME_V8(ev_now(EV_DEFAULT_UC))));
+}
+
 static void Tick(void) {
   // Avoid entering a V8 scope.
   if (!need_tick_cb) return;
@@ -220,6 +227,7 @@ static void PrepareTick(EV_P_ ev_prepare *watcher, int revents) {
 static void CheckTick(EV_P_ ev_check *watcher, int revents) {
   assert(watcher == &check_tick_watcher);
   assert(revents == EV_CHECK);
+  UpdateLoopTime();
   Tick();
 }
 
@@ -1558,6 +1566,9 @@ static Handle<Value> Now(const Arguments& args) {
 static void Load(int argc, char *argv[]) {
   HandleScope scope;
 
+  // some constants
+  loop_time_symbol = NODE_PSYMBOL("loopTime");
+
   Local<FunctionTemplate> process_template = FunctionTemplate::New();
   node::EventEmitter::Initialize(process_template);
 
-- 
1.7.3.1

tstamp-output.txt

process.now().getTime()    ->   13.70 MHz
process.loopTime.getTime() ->   37.31 MHz
Date.now()                 ->    7.97 MHz
(new Date).getTime()       ->    5.30 MHz
-----------
process.now().getTime()    ->   13.89 MHz
process.loopTime.getTime() ->   39.06 MHz
Date.now()                 ->    7.79 MHz
(new Date).getTime()       ->    5.45 MHz
-----------
process.now().getTime()    ->   13.89 MHz
process.loopTime.getTime() ->   39.68 MHz
Date.now()                 ->    7.76 MHz
(new Date).getTime()       ->    5.90 MHz
-----------
process.now().getTime()    ->   13.66 MHz
process.loopTime.getTime() ->   38.46 MHz
Date.now()                 ->    7.69 MHz
(new Date).getTime()       ->    5.90 MHz
-----------
process.now().getTime()    ->   14.12 MHz
process.loopTime.getTime() ->   40.65 MHz
Date.now()                 ->    7.74 MHz
(new Date).getTime()       ->    5.92 MHz
-----------
process.now().getTime()    ->   13.77 MHz
process.loopTime.getTime() ->   39.06 MHz
Date.now()                 ->    8.13 MHz
(new Date).getTime()       ->    5.75 MHz

tstamp-test.js

var kLoops= 5e5;

String.prototype.pad= function pad (len) {
  var str= this;
  while (str.length < len) str= " "+ str;
  return str;
}

function loop () {
  
  if (process.now) {
  var ctr= kLoops;
  var t= Date.now();
  while (ctr--) {
    process.now().getTime(); process.now().getTime(); process.now().getTime(); process.now().getTime(); process.now().getTime();
    process.now().getTime(); process.now().getTime(); process.now().getTime(); process.now().getTime(); process.now().getTime();
  }
  t= Date.now()- t;
  console.log("process.now().getTime()    ->"+ (kLoops*10/t/1e3).toFixed(2).pad(8)+ " MHz");
  }
  
  if (process.loopTime) {
  var ctr= kLoops;
  var t= Date.now();
  while (ctr--) {
    process.loopTime.getTime(); process.loopTime.getTime(); process.loopTime.getTime(); process.loopTime.getTime(); process.loopTime.getTime();
    process.loopTime.getTime(); process.loopTime.getTime(); process.loopTime.getTime(); process.loopTime.getTime(); process.loopTime.getTime();
  }
  t= Date.now()- t;
  console.log("process.loopTime.getTime() ->"+ (kLoops*10/t/1e3).toFixed(2).pad(8)+ " MHz");
  }
  
  var ctr= kLoops;
  var t= Date.now();
  while (ctr--) {
    Date.now(); Date.now(); Date.now(); Date.now(); Date.now();
    Date.now(); Date.now(); Date.now(); Date.now(); Date.now();
  }
  t= Date.now()- t;
  console.log("Date.now()                 ->"+ (kLoops*10/t/1e3).toFixed(2).pad(8)+ " MHz");

  var ctr= kLoops;
  var t= Date.now();
  while (ctr--) {
    (new Date).getTime(); (new Date).getTime(); (new Date).getTime(); (new Date).getTime(); (new Date).getTime();
    (new Date).getTime(); (new Date).getTime(); (new Date).getTime(); (new Date).getTime(); (new Date).getTime();
  }
  t= Date.now()- t;
  console.log("(new Date).getTime()       ->"+ (kLoops*10/t/1e3).toFixed(2).pad(8)+ " MHz");
  
  console.log("-----------")
  
  setTimeout(loop, 999);
}
setTimeout(loop, 999);

NOTE: there is a bug on the second patch, where process.loopTime is not set on the first loop

patches rebased on HEAD: dbf0d6b ClearWeak on ObjectWraps...