Hi,

Came across this post in rust-lang subreddit about the regex benchamrks. Scala surprisingly outperforms D. LDC also gives a good advantage for efficiency of D.

http://vaskir.blogspot.ru/2015/09/regular-expressions-rust-vs-f.html

On Tuesday, 5 January 2016 at 17:52:39 UTC, Karthikeyan wrote:
> Hi,
>
> Came across this post in rust-lang subreddit about the regex benchamrks. Scala surprisingly outperforms D. LDC also gives a good advantage for efficiency of D.
>
> http://vaskir.blogspot.ru/2015/09/regular-expressions-rust-vs-f.html

I'm willing to bet the bad result D has come from the use of DMD.

Honestly, pushing DMD as the reference implementation cost us quite a lot on the PR side of things. D appears to be slower that it really is.

Dne 5.1.2016 v 19:09 deadalnix via Digitalmars-d napsal(a):
> On Tuesday, 5 January 2016 at 17:52:39 UTC, Karthikeyan wrote:
>> Hi,
>>
>> Came across this post in rust-lang subreddit about the regex benchamrks. Scala surprisingly outperforms D. LDC also gives a good advantage for efficiency of D.
>>
>> http://vaskir.blogspot.ru/2015/09/regular-expressions-rust-vs-f.html
> 
> I'm willing to bet the bad result D has come from the use of DMD.
> 
> Honestly, pushing DMD as the reference implementation cost us quite a lot on the PR side of things. D appears to be slower that it really is.

To be fair, they have results for DMD and LDC:

regex - 10.6 s (DMD), 7.8 s (LDC)
ctRegex! - 6.9 s (DMD), 6.6 s (LDC)

Although no information about compiler switches.

On Tuesday, 5 January 2016 at 18:13:00 UTC, Martin Drašar wrote:
> Dne 5.1.2016 v 19:09 deadalnix via Digitalmars-d napsal(a):
>> On Tuesday, 5 January 2016 at 17:52:39 UTC, Karthikeyan wrote:
>>> Hi,
>>>
>>> Came across this post in rust-lang subreddit about the regex benchamrks. Scala surprisingly outperforms D. LDC also gives a good advantage for efficiency of D.
>>>
>>> http://vaskir.blogspot.ru/2015/09/regular-expressions-rust-vs-f.html
>> 
>> I'm willing to bet the bad result D has come from the use of DMD.
>> 
>> Honestly, pushing DMD as the reference implementation cost us quite a lot on the PR side of things. D appears to be slower that it really is.
>
> To be fair, they have results for DMD and LDC:
>
> regex - 10.6 s (DMD), 7.8 s (LDC)
> ctRegex! - 6.9 s (DMD), 6.6 s (LDC)
>
> Although no information about compiler switches.

Relevant reddit discussion.https://www.reddit.com/r/rust/comments/3zh95h/regular_expressions_rust_vs_f_vs_scala_vs_d/

On Tuesday, 5 January 2016 at 17:52:39 UTC, Karthikeyan wrote:
> Hi,
>
> Came across this post in rust-lang subreddit about the regex benchamrks. Scala surprisingly outperforms D. LDC also gives a good advantage for efficiency of D.
>
> http://vaskir.blogspot.ru/2015/09/regular-expressions-rust-vs-f.html

I notice he's using readln() instead of readln(buf) in the D solution, would having D re-use the buffer make a substantial improvement in performance?

On 01/05/2016 01:13 PM, Martin Drašar via Digitalmars-d wrote:
> Dne 5.1.2016 v 19:09 deadalnix via Digitalmars-d napsal(a):
>> On Tuesday, 5 January 2016 at 17:52:39 UTC, Karthikeyan wrote:
>>> Hi,
>>>
>>> Came across this post in rust-lang subreddit about the regex
>>> benchamrks. Scala surprisingly outperforms D. LDC also gives a good
>>> advantage for efficiency of D.
>>>
>>> http://vaskir.blogspot.ru/2015/09/regular-expressions-rust-vs-f.html
>>
>> I'm willing to bet the bad result D has come from the use of DMD.
>>
>> Honestly, pushing DMD as the reference implementation cost us quite a
>> lot on the PR side of things. D appears to be slower that it really is.
>
> To be fair, they have results for DMD and LDC:
>
> regex - 10.6 s (DMD), 7.8 s (LDC)
> ctRegex! - 6.9 s (DMD), 6.6 s (LDC)
>
> Although no information about compiler switches.

The benchmark measures a mixture of times, not only regex time. Could somebody tweak the benchmark and figure what the individual timings are (I/O vs. regex vs. the pipeline vs. appending)?  -- Andrei

On Tuesday, 5 January 2016 at 18:19:23 UTC, Gerald wrote:
> I notice he's using readln() instead of readln(buf) in the D solution, would having D re-use the buffer make a substantial improvement in performance?

Yep. It's a life-changer. There's a before and an after.

On Tuesday, 5 January 2016 at 18:21:39 UTC, Basile B. wrote:
> On Tuesday, 5 January 2016 at 18:19:23 UTC, Gerald wrote:
>> I notice he's using readln() instead of readln(buf) in the D solution, would having D re-use the buffer make a substantial improvement in performance?
>
> Yep. It's a life-changer. There's a before and an after.

Tried it on my laptop, only shaved half a second off the total time, was hoping for more.

On Tuesday, 5 January 2016 at 17:52:39 UTC, Karthikeyan wrote:
> Hi,
>
> Came across this post in rust-lang subreddit about the regex benchamrks. Scala surprisingly outperforms D. LDC also gives a good advantage for efficiency of D.
>
> http://vaskir.blogspot.ru/2015/09/regular-expressions-rust-vs-f.html

k, I optimized it for fun
https://paste.ee/p/Bb1Ns
I also found an mmfile bug if someone could report it for me, if I don't add a root to the mmfile contents(or disable the GC) the program will crash

ctregex for both
his:
Elapsed: 6432
mine:
Elapsed: 3123

ldc -O3 -release -boundscheck=off -singleobj regex.d
does not compile with the latest gdc on arch linux(no lineSplitter)

you could probably get it faster by reusing a buffer(I forget which call this is, but it exists in phobos) when reading the file but I felt like using mmfile as I've never used it before. Make sure you use a block-size buffer(e.g, 4096)

Bye.

On Tuesday, 5 January 2016 at 20:04:35 UTC, rsw0x wrote:
>[...]

Anyone on linux who could imgur a callgraph please? Premature optimisation and all that.