On Tue, 26 Sep 2017 11:03:11 -0700, [email protected] wrote:
> On Thu, 22 Jun 2017 10:29:59 -0700, [email protected] wrote:
> > I'd expect the fancy Unicode versions of <=, >=, and != to perform
> > equally well, instead the
> > ≥ and ≤ are 36x slower than their Texas companions and ≠ is 15x
> > slower.
> >
> > Here's the timings for >= vs ≥:
> >
> > m: my $x = rand; for ^1000_000 { $ = $x >= 1_000_000_000_000 }; say
> > now - INIT now;
> > rakudo-moar 43c176: OUTPUT: «0.74663187»
> > m: my $x = rand; for ^1000_000 { $ = $x ≥ 1_000_000_000_000 }; say
> > now
> > - INIT now;
> > rakudo-moar 43c176: OUTPUT: «(timeout)»
> > m: my $x = rand; for ^1000_0 { $ = $x ≥ 1_000_000_000_000 }; say now
> > -
> > INIT now;
> > rakudo-moar 43c176: OUTPUT: «0.2661272»
> > m: say 0.2661272*100 / 0.729002
> > rakudo-moar 43c176: OUTPUT: «36.505689»
>
>
> So I made the static optimizer change Mexico ops to Texas versions, so
> this problem no longer exist. So, should the ticket be closed?
>
> Fixed in https://github.com/rakudo/rakudo/commit/6ec21cb473
>
> I tried writing a test, but couldn't get anything usable. My attempt
> was this:
>
> use Test;
> subtest 'performance of ≤, ≥, ≠ compared to Texas versions' => {
> sub measure (&code) { code for ^300; with now { code for ^100_000;
> now - $_ } }
>
> is-approx { rand ≤ rand }.&measure, { rand <= rand }.&measure, '≤',
> :rel-tol<.5>;
> is-approx { rand ≥ rand }.&measure, { rand >= rand }.&measure, '≥',
> :rel-tol<.5>;
> is-approx { rand ≠ rand }.&measure, { rand != rand }.&measure, '≠',
> :rel-tol<.5>;
> }
So the optimizer fix didn't do a full job. There were still cases that ended up
86x slower:
When chained:
<Zoffix__> m: $ = rand ≤ rand ≤ rand for ^100_000; say now - INIT now
<camelia> rakudo-moar a042fd927: OUTPUT: «2.91023964»
<Zoffix__> m: $ = rand <= rand <= rand for ^100_000; say now - INIT now
<camelia> rakudo-moar a042fd927: OUTPUT: «0.094577»
Or when user defines their own version of the ASCII op:
<Zoffix__> m: $ = rand ≤ rand for ^100_000; say now - INIT now
<camelia> rakudo-moar a042fd927: OUTPUT: «0.0474443»
<Zoffix__> m: class Foo {}; sub infix:«<=» (Foo, Foo) {}; $ = rand ≤ rand
for ^100_000; say now - INIT now
<camelia> rakudo-moar a042fd927: OUTPUT: «1.94282032»
Some proposed to substitute Unicode versions for Texas ones during parsing and
codegen, but the only way I
know how to do that would make user's use of `≠` use a custom `!=` op, if one
exists.
It's possible we *do* want to declare that we do such aliasing: a Unicode op is
just a grammatical alias
to the ASCII op and gets rewritten to it. If there's a consensus to do that, it
should be done for all the ops,
even ones that don't have this performance issue (which is due to capture
slipping).
For now, I basically restored lizmat++'s original fix adding whatever datish
ops that were
originally missing as well: https://github.com/rakudo/rakudo/commit/6ad06fad9f
