Re: Emacs Lisp JIT Compiler

["Clément Pit-Claudel" <cpitclaudel@gmail.com>]

On 2018-08-15 20:32, Tom Tromey wrote:
>>>>>> "Clément" == Clément Pit-Claudel <cpitclaudel@gmail.com> writes:
> 
> Clément> I compiled and installed libjit, and things seem to build fine here.
> 
> Thank you for trying it.
> 
> Clément> Benchmarking a simple loop yields an impressive 4x speedup (from 1
> Clément> second down to 0.25s).  However, benchmarking a larger application
> Clément> seems to yield a 30% slowdown (from 5.5s to 7.5s).  I haven't
> Clément> investigated why yet.  Have you seen similar variations?
> 
> I have not really done that much benchmarking.
> However, please send me your test case (or tell me what it is) and I
> will take a look.

Hi Tom,

My simple benchmark was this, and wow did that get fast:

;; -*- lexical-binding: t; -*-

(defun test ()
  (let ((sum 0))
    (dotimes (n (* 15 1000 1000))
      (setq sum (+ sum 1))
      (setq sum (- sum 1))
      (setq sum (+ sum 1))
      (setq sum (- sum 1))
      (setq sum (+ sum 1)))
    sum))

My application benchmark that got a bit slower is essentially fontifying and exporting to LaTeX about 200k lines of Python code.  The app is at https://github.com/cpitclaudel/esh.  If you clone it you can run this:

    # Generate test data
    cd /usr/lib/python3.5/; cat turtle.py inspect.py doctest.py pydoc.py tarfile.py pickletools.py argparse.py > /tmp/bench.py
    # Run the benchmark
    time EMACS=/build/emacs/master/src/emacs bin/esh2tex --standalone /tmp/bench.py

The EMACS= part is needed because ESH starts an Emacs server in the background.

Cheers and thanks for your work!
Clément.