Perl 6 and performance

by talexb (Chancellor) on Feb 09, 2012 at 17:33 UTC

P.S. I'm sad to see that perlmonks is slowly becoming more like reddit, where problems are met with rancorousness instead of being discussed on a technical level.

I think the peevishness is a result of hype exhaustion on the topic of Perl6. I'm thrilled that a barrel-full of very bright people are working on the next generation of Perl, but I'll happily wait till it's cooked, and I'll continue to happily use the excellent Perl5 in the meantime. It's worked very well for me for the last 15 years, and it's still very much alive.

And, as the kids say, "It's all good."

Alex / talexb / Toronto

"Groklaw is the open-source mentality applied to legal research" ~ Linus Torvalds

by hippo (Bishop) on Feb 09, 2012 at 18:29 UTC

My point of view is that Perl6 is not so much a successor to Perl5 but rather an alternative to it. To that end it might have been preferable not to call it Perl6 but maybe something like PerlVM that would indicate that it takes a radically different approach to "classic" Perl.

If/when Perl6 does reach release-level maturity it probably won't supplant Perl5. The two can quite happily co-exist as different implementations which share (most of) a common syntax. At that point we can all choose the right tool for the job at hand.

Just my tuppence.

Update: It's now October 2019 and "Perl6" is now "Raku" so that, belatedly but thankfully, solves the naming problem. The syntax is probably more divergent from Perl than I anticipated but the two languages (and communities) can now co-exist and provide two different tools for every programmer.

by kikuchiyo (Hermit) on Feb 09, 2012 at 19:32 UTC

Thank you for the detailed answer. It indeed makes the cause of the problem clear.

For me, it's more natural to write a floating point constant one as 1.0, however, that doesn't work. And this won't even run:

time ./perl6 -e 'my $s; for 1..10000 {$s+=1./$_**2};say $s'
===SORRY!===
Unable to parse blockoid, couldn't find final '}' at line 2
[download]

I've also tried to explicitly declare the loop variable as a floating point:

./perl6 -e 'my $s;my Num $i;for 1..10000 -> $i {$s+=1/$i**2};say $s'
[download]

This has no effect, as can be seen from the following:

./perl6 -e 'my Num $s;my Num $i;for 1..10000 -> $i {$s+=1/$i**2};say $
+s'
Type check failed in assignment to '$s'; expected 'Num' but got 'Rat'
  in method reify at src/gen/CORE.setting:4471
  in method reify at src/gen/CORE.setting:4376
  in method reify at src/gen/CORE.setting:4376
  in method gimme at src/gen/CORE.setting:4740
  in method eager at src/gen/CORE.setting:4715
  in method eager at src/gen/CORE.setting:1028
  in sub eager at src/gen/CORE.setting:5000
[download]

Does this mean that even though I declare $i as a Num, it's still an integer when used as a loop variable? Is it because the .. operator supplies integers?

P.S. I'm sad to see that perlmonks is slowly becoming more like reddit, where problems are met with rancorousness instead of being discussed on a technical level.

I admit that I posed the original question in a slightly more trollish way than necessary, and I apologize for the inconvenience I might have created. I didn't intend to denigrate the effort of the Perl 6 developers - an effort which is nothing short of heroic.

However, I do think that the problems with the current state of Perl 6 go way beyond the technical level, and pretending that these problems can be treated at the mere technical level is an attitude that does more harm than good on the long term.

Perl 6 - second systems done right

by moritz (Cardinal) on Feb 09, 2012 at 19:59 UTC

To clarify things, 1. is not a valid number in Perl 6. 1.0 is a Rat, 1e0 or 1.0e0 are Num.

I've also tried to explicitly declare the loop variable as a floating point:

There are two issues with it. The first is that you don't declare the loop variable to be a Num, but an outer variable of the same name. In -> $i { ... } the part between the arrow and the block is a signature, which declares a new variable. So it's like writing

my Num $i;
sub ($i) { # new $i here

}
[download]

A way to fix that is writing -> Num $i { }, but then you get a type check failure because 1..1000 indeed produces Ints, not Nums. So either you coerce to Num somewhere (for example $i.Num ** 2), or you write the range as 1e0 .. 1e3.

I admit that I posed the original question in a slightly more trollish way than necessary, and I apologize for the inconvenience I might have created. I didn't intend to denigrate the effort of the Perl 6 developers - an effort which is nothing short of heroic.

My side remark was more about _foo's trolling, not about your original question, which I think is 100% valid, and a good bug report at that. Sorry if that came out wrong on my part. User feedback like yours is what we need, and one of the reasons for making the star releases in the first place.

Re^4: Perl 6 and performance

by kikuchiyo (Hermit) on Feb 09, 2012 at 21:00 UTC

Re^5: Perl 6 and performance

by moritz (Cardinal) on Feb 10, 2012 at 05:52 UTC

Re: Perl 6 and performance
by Old_Gray_Bear (Bishop) on Feb 09, 2012 at 16:53 UTC

First, make it run
Second, make it run right
Finally, make it run fast

----
I Go Back to Sleep, Now.

OGB

by Anonymous Monk on Feb 10, 2012 at 14:59 UTC

The stages of Perl 6 development

a. First, make a small part of it run.

b. Then make that small part run on a hundred VM's

c. Then re factor all those 100's of parts every 2 years.

Re: Perl 6 and performance
by raiph (Deacon) on May 27, 2015 at 04:46 UTC

»»» This post is about alpha status Perl 6, not rock solid Perl 5 «««

I just encountered this post (thanks hippo) and thought an update would be helpful.

The OP suggests that running this "benchmark" with the initial Rakudo Star release from 2010 was about 4000x slower than Perl 5.

Now, 5 years later, a current Rakudo looks like it's something like 50x slower than a current Perl 5 for this particular "benchmark". (The bogus behaviors -- NaNs and quadratic slow down -- have of course been fixed.)

raiph@hack:~$ time perl6 -e 'my $s; for 1..10000 {$s+=1/$_**2};say $s'
1.64483407184807

real    0m0.355s
user    0m0.316s
sys     0m0.036s

raiph@hack:~$ time perl -E 'my $s; for (1..10000) {$s+=1/$_**2};say $s
+'
1.64483407184807

real    0m0.007s
user    0m0.004s
sys     0m0.000s
[download]

»ö« ^{. o O ( "the celebrity tell-all of the Perl-6 cult?" )}

[reply]
[d/l]

by Anonymous Monk on Feb 26, 2016 at 19:59 UTC

echo %time% - perl5
call c:\strawberry_perl\portableshell.bat -E "my $s; for ( 1..1000000 
+) { $s+=1/$_**2 }; say $s"
echo !time!

echo %time% - perl6
call perl6 -e "my $s; for ( 1..1000000 ) { $s+=1/$_**2 }; say $s"
echo %time%
[download]

14:03:07.14 - perl5
1.64493306684877
14:03:07.64
14:03:07.65 - perl6
1.64493306684877
14:03:19.05
[download]

by BrowserUk (Patriarch) on Feb 27, 2016 at 02:59 UTC

So, perl5 took .5 sec and perl6 took 11.4 secs, making perl6 almost 23 times slower than perl5. I really hope this is improved on in subsequent releases of perl6. John

My considered assessment is that in order to be able to support the needs of MOP, and installable parsers, the levels of indirection required within the opcode tree are such that Perl6 will never be able to achieve the performance of Perl5; much less (uncompiled) Java and similar.

From my brief appraisals of the performance it currently achieves, and an even more brief exploration of the source code, I think it quite unlikely that the Perl6 syntax will ever be able to get within an order of magnitude of Perl5 performance as a purely interpreted language. I think it would require a full optimising compiler to achieve any real breakthrough in its performance.

It is possible that a JIT compiler could fold out some of the indirections, but I suspect that it would require serious machine level skills on each targeted platform for that to be achieved.

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority". I knew I was on the right track :)

In the absence of evidence, opinion is indistinguishable from prejudice.

by coke (Acolyte) on Feb 29, 2016 at 17:41 UTC

In Perl 6, that math is going to default to Rationals, meaning you're keeping around a numerator and denominator and doing a bit more math than you might otherwise be expecting than p5's floats.

The point of the Christmas release was to stabilize the spec. Work in the upcoming year on Rakudo Perl 6 is going to target optimizations in both JIT and code generation.

by Your Mother (Archbishop) on Feb 26, 2016 at 20:21 UTC

While I don’t find this kind of benchmark too exciting I will add that the difference is greater on OS X; well over a hundred times faster for 5. It’s easy, for me anyway, to forget how well tuned 5 is…

# This is perl 5, version 18, subversion 2 (v5.18.2) built for darwin-
+2level
moo@cow[22]~>time perl -E 'my $s; for ( 1..1_000_000 ) { $s+=1/$_**2 }
+; say $s'
1.64493306684877
0.111u 0.000s 0:00.11 100.0% 0+0k 0+2io 0pf+0w

# Both the last two Rakudo builds of 6.c produced same results
moo@cow[30]~>time perl6 -e 'my $s; for ( 1..1_000_000 ) { $s+=1/$_**2 
+}; say $s'
1.64493306684877
16.198u 0.300s 0:16.55 99.6% 0+0k 0+0io 0pf+0w
[download]

[reply]
[d/l]

Re: Perl 6 and performance
by Anonymous Monk on Feb 11, 2012 at 03:46 UTC

Every "programming language that has been around for a while" has to cope with irrelevance ... and Perl-6 is at that point now. The language reached its true zenith with Perl-5, and a group of well-meaning people tried to produce something better while at the same trying to bootstrap on top of what territory Perl-5 had already mastered. But, what they have managed to come up with is ... ADD 1 TO PERL GIVING PERL. It truly has nothing to do with "Perl," in the same way that "object-oriented COBOL" has nothing to do with COBOL. And, during the many years that Perl-6 has foundered in the birthing stage, the river has moved on. Programming languages, even good ones, aren't that hard to make anymore. They don't attract the following that they once did. They do not have the "single target" that they used to. Even if Perl-6 does make it to a deliverable, it will not attract the interest that its erstwhile predecessor has earned.