Re: Idle musings on doing E over again

On Oct 2, 2012, at 4:06, Thomas Leonard wrote:

> On 2 October 2012 03:16, Bill Frantz <[email protected]> wrote:
> I profiled E's startup a while back, but there
> was nothing obviously the problem, just many little things.
> [...]
> E's startup time is a lot worse than Java's (even though Java is
> indeed far too slow):
> 
> $ time python hello.py
> python hello.py  0.02s user 0.00s system 84% cpu 0.024 total
> 
> $ time java Hello
> java Hello  0.06s user 0.02s system 98% cpu 0.082 total
> 
> $ time rune hello.e
> rune hello.e  9.23s user 0.34s system 200% cpu 4.785 total

My hypothesis, which I don't recall the origin of and so may or may not be based on actual analysis, is that most of this time is spent in

• evaluating static initializers and global tables in E's Java code (which includes things like SafeJ tables)

• parsing/expanding/evaluating one-off E code

These could be improved by figuring out how to 'compile' the E implementation better, i.e. precompute the  constant stuff.

Here's an experiment that could be tried: run hello.e not by the usual 'rune' (which ends up invoking a rather elaborate E program which does special things for 'top-level' programs), but by a Java stub which does nothing but create a vat, then parse and evaluate the code.

-- 
Kevin Reid                                  <http://switchb.org/kpreid/>