timers: improve Timer.now() performance

Record the start time so we can make the return value of Timer.now()
relative to it, increasing the chances that it fits in a tagged integer
instead of a heap-allocated double, at least for the first one or two
billion milliseconds.

PR-URL: https://github.com/nodejs/io.js/pull/2256
Reviewed-By: Trevor Norris <trev.norris@gmail.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/test/parallel/test-timers-now.js b/test/parallel/test-timers-now.js
new file mode 100644
index 0000000000..466bd064b8
--- /dev/null
+++ b/test/parallel/test-timers-now.js
@@ -0,0 +1,8 @@
+'use strict';
+
+const common = require('../common');
+const assert = require('assert');
+
+// Return value of Timer.now() should easily fit in a SMI right after start-up.
+const Timer = process.binding('timer_wrap').Timer;
+assert(Timer.now() < 0x3ffffff);