joyent/node — pull request #3727 by davepacheco (2012-07-17 22:32:58+00:00)
Title: genv8constants is much slower than necessary due to Python pipe buffering

For details, see:

http://docs.python.org/library/subprocess.html?highlight=subprocess.popen#subprocess.Popen

Here's the relevant bit, with emphasis added:

> *bufsize*, if given, has the same meaning as the corresponding argument
> to the built-in open() function: 0 means unbuffered, 1 means line buffered,
> any other positive value means use a buffer of (approximately) that size.
> A negative bufsize means to use the system default, which usually means
> fully buffered. **The default value for bufsize is 0 (unbuffered).**