21 Feb
2015
21 Feb
'15
11:14 a.m.
Hey,
I was not aware about some exponential element in the overall complexity,
it is strange and I will investigate it. Thank you Usman, for pointing this
out.
In general, it is hard to add features into the PetitParser and preserve
performance. Therefore, we work on a tool, that will take PetitParser,
analyze it and generates faster parser. The idea is to use PetitParser
while developing the grammar and than generate a fast parser for "real"
use. We hope we will be present the tool during the next ESUG.
Cheers,
Jan
On 20 February 2015 at 17:47, Usman Bhatti <usman.bhatti(a)gmail.com> wrote:
I executed the script that I shared earlier in this
thread and I see a
considerable performance improvement in the latest version of PP. The
attached chart shows the comparison chart between PP v 1.51 (green) with
the newer version (red). For shorter strings (i.e. to the left on x-axis),
the execution time is almost comparable to the previous version of
PetitParser that dates before changes introduced by Jan.
However, when I take the new version and parse the code source of larger
code bases, the execution time still get a hit. For example, parsing 100K
lines takes almost twice longer. The increase is exponential with even
larger ones. That is consistent with results we see in the graph (the
larger the chain to be parsed i.e. going from left to right in the x-axis,
the higher the performance penalty). Meaning I still prefer the older
version.
What will be good is to prepare some benches with Java Parser in PP, as it
is open source, and a set of programs (e.g. ArguUML) that can serve as a
standard to test execution time for PP that we can run as a jenkins service.
[image: Inline image 1]
regards.
On Fri, Feb 20, 2015 at 9:09 AM, Tudor Girba <tudor(a)tudorgirba.com> wrote:
Great news.
@Usman: could you check?
Doru
On Fri, Feb 20, 2015 at 9:04 AM, Jan Kurš <kurs.jan(a)gmail.com> wrote:
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Hey all, Please note that a new version in of
PetitParser (JanKurs-271)
should improve performance roughly comparable to the original performance.
On my computer, I got improvement from 3900ms to 1300ms.
Cheers,
Jan
On 1 February 2015 at 22:55, Jan Kurš <kurs.jan(a)gmail.com> wrote:
--
www.tudorgirba.com
"Every thing has its own flow"
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Hey all, thanks for the report, I will have a
look at it asap.
Cheers Jan
On 1 Feb 2015 20:55, "Usman Bhatti" <usman.bhatti(a)gmail.com> wrote:
>
>
> On Fri, Jan 30, 2015 at 9:36 PM, Sven Van Caekenberghe <sven(a)stfx.eu>
> wrote:
>
>> Usman, this is a really cool bug report !
>>
>
> Thanks :)
>
>
>>
>> > On 30 Jan 2015, at 16:36, Usman Bhatti <usman.bhatti(a)gmail.com>
>> wrote:
>> >
>> > Here is a script that shows the factor of 2 in time taken for
>> parsing. The idea of the script is to introduce several wrong branches
>> before hitting the correct one (originally proposed by Guillaume).
>> >
>> > |rule wrongBranches|
>> > [wrongBranches := (25 to: 45) inject: 24 asCharacter asParser into:
>> [:acc :each | acc / each asCharacter asParser].
>> > rule := PPDelegateParser new.
>> > rule setParser: $a asParser / ((wrongBranches / $. asParser), rule).
>> > rule parse: (String streamContents: [ :s |
>> > 30000 timesRepeat: [s nextPut: $.]. s nextPut: $a ])]
>> timeToRun
>> >
>> >
>> > Below are the graphs that were generated when varying the string
>> length provided to the above parser description. Green part shows the time
>> taken by the older version and the red part with the latest PP.
>> >
>> > <graph.png>
>> >
>> > Data values and graph generated by the script in the attached file.
>> >
>> > regards.
>> >
>> > usman
>> >
>> > On Fri, Jan 30, 2015 at 1:30 PM, Tudor Girba <tudor(a)tudorgirba.com>
>> wrote:
>> > Hi,
>> >
>> > Hmm. I thought this was fixed and that you said at the end that the
>> performance penalty is no longer a factor of 2.
>> >
>> > Do you have a simple example for checking the simple case of 2x
>> performance loss?
>> >
>> > Doru
>> >
>> >
>> > On Fri, Jan 30, 2015 at 12:28 PM, Usman Bhatti <
>> usman.bhatti(a)gmail.com> wrote:
>> > Hi,
>> >
>> > Since the work on the integration of PPContext in PetitParser,
>> there is significant performance degradation. I have already mentioned that
>> on simple grammar the factor is about 2. But on complex grammar (for
>> example, our proprietary parser for 4D language ), we have seen that
>> degradation is goes well beyond this factor. So, for example, for 800K
>> lines that we parse in under 10 minutes without PPContext work, with the
>> latest version it goes beyond 2h.
>> >
>> > I have not been able to reproduce my case on simple grammars. May
>> be we can have some benchmarks using open source parsers and large code
>> bases (e.g. PP Java Parser on JHotDraw or ArgoUML).
>> >
>> > Currently, I circumvent this issue by using PP v1.51 but I can
>> provide relevant feedback and run benches on any improvements.
>> >
>> > regards.
>> >
>> > Usman
>> >
>> > _______________________________________________
>> > Moose-dev mailing list
>> > Moose-dev(a)iam.unibe.ch
>> > https://www.iam.unibe.ch/mailman/listinfo/moose-dev
>> >
>> >
>> >
>> >
>> > --
>> > www.tudorgirba.com
>> >
>> > "Every thing has its own flow"
>> >
>> > _______________________________________________
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>> > Moose-dev(a)iam.unibe.ch
>> > https://www.iam.unibe.ch/mailman/listinfo/moose-dev
>> >
>> >
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