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From Philippe Mouawad <philippe.moua...@gmail.com>
Subject Re: Use ThreadLocalRandom instead of Random
Date Mon, 21 Jan 2013 20:56:04 GMT
On Mon, Jan 21, 2013 at 9:45 PM, sebb <sebbaz@gmail.com> wrote:

> On 21 January 2013 20:27, Philippe Mouawad <philippe.mouawad@gmail.com>
> wrote:
> > Hello Sebb,
> > My answers below.
> >
> > Regards
> > Philippe
> >
> > On Mon, Jan 21, 2013 at 6:22 PM, sebb <sebbaz@gmail.com> wrote:
> >
> >> On 21 January 2013 12:28, Philippe Mouawad <philippe.mouawad@gmail.com>
> >> wrote:
> >> > Hello,
> >> > Java 7 introduced ThreadLocalRandom which has much better performances
> >> than
> >> > using Random as static instance.
> >> > See:
> >> >
> >> >
> >>
> http://docs.oracle.com/javase/tutorial/essential/concurrency/threadlocalrandom.html
> >> >
> >>
> http://niklasschlimm.blogspot.fr/2012/01/java-7-how-to-write-really-fast-java.html
> >> >
> >> >
> >> > Implementation is here for Java6 but can we use it with Apache
> License ?:
> >> >
> >>
> https://github.com/codahale/metrics/blob/master/metrics-core/src/main/java/com/yammer/metrics/stats/ThreadLocalRandom.java
> >>
> >> That appears to be public domain.
> >> Not sure of whether that is allowable or not.
> >>
> >> >
> >> > Or should we migrate to Java 7 as Java6 will be soon EOL ?
> >>
> >> Is the performance of Random a significant problem for JMeter?
> >> Does it affect all tests? Or just some test elements?
> >> If not, then I don't think it's worth the effort.
> >>
> >
> > I will affect:
> > - RandomVariableConfig
> > - RandomController
> > - RandomTimer
>
> Yes, but I doubt these are used frequently.
>

I agree

>
> > - RegexpExtractor => Used a lot
> > - HtmlExtractor => Hope it will be :-)
> > - __regexFunction
> > - AnchorModifier
>
> But is the random option used frequently?
>
Well I must say I use it on almost every Test Plan I did these last years
:-)

If random is still called even if not selected, then that should be
> fixed anyway.
>
No that's OK, it is called only if 0 is selected.

>
> > So maybe we could at least impact:
> > - RegexpExtractor => Used a lot
> > - HtmlExtractor => Hope it will be :-)
> > - RandomController
>
> Yes, but will speeding up calls to Random affect a test run by much?
>

Well with high number of threads I think it begins impacting.


> e.g. by how much does using random RE slow down a sample test compared
> with using a fixed RE?
> Is it really significant?
>

I didn't test but in my opinion, whenever we can improve core parts we
should.

As I am not sure it will cost us a lot.
But if you have some other fields to improve in mind, let's work on it.

You still didn't answer to my mail on logging framework replacement ;-)



> >
> >>
> >> As to whether to require Java 7, I suspect Java 6 will still be used
> >> by many (especially businesses) until long after EOL (and remember
> >> users can pay to have longer support).
> >>
> >
> > I agree with you this policy applies for Application servers, but for
> tools
> > like JMeter I don't think it does. From my experience as a JMeter user,
> we
> > always were able to have a particular Java version installed.
>
> >>
> >> If a move to Java 7 would allow the use of new APIs that provide
> >> significant performance improvements then it might be worth doing.
> >> But we do need to be aware that requiring Java 7 as a minimum may well
> >> exclude some users.
> >>
> >
> > Same answer as before.
> > I think if we cannot use  ThreadLocalRandom as copy / paste in JMeter
> > source, it is worth thinking about moving to Java 7.
> > Who can help us on this license problem ?
> >
> >>
> >> > Regards
> >> > Philippe M.
> >>
> >
> >
> >
> > --
> > Cordialement.
> > Philippe Mouawad.
>



-- 
Cordialement.
Philippe Mouawad.

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