Benchmark of D against other languages

Martin Nowak via Digitalmars-d digitalmars-d at
Tue Mar 31 14:30:54 PDT 2015

On 03/31/2015 09:07 PM, Andrei Alexandrescu wrote:
> True. I don't have time to put this on my plate, does anyone? -- Andrei

Very little, here is my outcome.

- brainfuck => better backend, better AA

  The switch in the run loop doesn't use a switch table.
  A lot of time is also spent on AA lookup.

- base64 => Base64.decode could be optimized

  It's already quite OK, but a few things could be done better.

- JSON => replace std.json, better AA and GC

  std.json is horribly bad + slow AA + slow GC. It got almost 3x faster
with the new GC changes though.

- matmul => need linear algebra library

  Can use std.numeric.dotProduct making it 33% faster.

  A good linear algebra library could radically improve this.

- havlak => alternative memory management, better AA and GC

  Got ~30% faster by the recent GC improvements.
  People too often new classes/create arrays like crazy (in loops).
  Using alternative memory management schemes is non-obvious or simply
too hard.

Action Points:

- I'll ask him to use dmd 2.067.0 and add ldc.

- We should finally acknowledge that dmd's backend has no future for
optimized code.

- D's AA is really slow, because of the C-ish interface.

  Making AA's a library type is mandatory, but difficult (already failed
thrice). I outlined clear acceptance criteria for a good AA
implementation here

  I currently lean towards adding a new implementation as `AA!(Key,
Value)` while slowly deprecating any semantic of the builtin AA that
can't be supported in a library implementation,
  then switching the implementations.
  Changing the builtin AA to a library type would break a lot of code,
because of the subtle semantic/attribute differences.

- We have a phobos candidate for a std.json replacement that comes with
a pull parser, we should move it to std.experimental asap.

- The GC can never be fast enough, but we're already working on it.

- Make GC alternatives more prominent, e.g. tell people to favor structs
over classes.

- Add getOrSet to AA

  Simple optimization for a common use-case.

- Use open addressing for AA

  Considerable speeds up AA, fairly simple to implement.

Now I spent way more than 1 hour on this ;).


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