Re: [core] ClassLoaderResourceLoader.getLibraryVersion(String) performace

[Martin Koci <ma...@aura.cz>]

I can confirm that problem was really in getLibraryVersion() - after few
hours of profiling (with simulation of 10 concurrent users) profiler
shows that JarEntry.nextElement() in was called over 300 000 000 times
(!) and getLibraryVersion() was total winner in cumulative time category
within org.apache packages.

Now with current trunk problem is gone and database queries are again my
prime time hogs ;-) 

Thanks,

Martin Kočí

Matthias Wessendorf píše v Pá 05. 02. 2010 v 18:20 +0100:
> Ah, ok :)
> 
> I am interested in what Martin comes up, regarding details.
> Hopefully it is only "getLibraryVersion(...)" ;-)
> 
> -Matthias
> 
> On Fri, Feb 5, 2010 at 6:09 PM, Leonardo Uribe <lu...@gmail.com> wrote:
> > Hi
> >
> > The code that serve resources on myfaces core comes from trinidad. There was
> > also other parts that comes from there too.
> >
> > Leonardo Uribe
> >
> > 2010/2/5 Matthias Wessendorf <ma...@apache.org>
> >>
> >> -hi,
> >>
> >> has one checked what Trinidad is offering for that ?
> >> I mean the code is pretty old (and therefore stable).
> >> Also at Oracle there is quite some PREF testing done...
> >>
> >> -Matthias
> >>
> >> On Fri, Feb 5, 2010 at 5:38 PM, Leonardo Uribe <lu...@gmail.com> wrote:
> >> > Hi
> >> >
> >> > Created MYFACES-2538 Remove resourceVersion and libraryVersion from
> >> > resource
> >> > identifiers.
> >> >
> >> > regards,
> >> >
> >> > Leonardo Uribe
> >> >
> >> > 2010/2/5 Leonardo Uribe <lu...@gmail.com>
> >> >>
> >> >> Hi
> >> >>
> >> >> Yes, that one is a big problem. There is no way to "traverse" a jar
> >> >> file
> >> >> without iterating over all entries to get the library version and
> >> >> resource
> >> >> version. That means the current algorithm do that all times a resource
> >> >> is
> >> >> rendered. This is really bad.
> >> >>
> >> >> I remember someone commented that on jsr-314-open at jcp.org mailing
> >> >> list,
> >> >> and checking the latest ri code (2.0.2-b10), library and resource
> >> >> version
> >> >> feature was removed. It seems a decision was taken there.
> >> >>
> >> >> Checking more, the topic describing this is:
> >> >>
> >> >> [jsr-314-open] Need guidance: invalid assumptions in design of resource
> >> >> versioning feature
> >> >>
> >> >> We should change our algorithm too to prevent this performance problem.
> >> >>
> >> >> regards,
> >> >>
> >> >> Leonardo Uribe
> >> >>
> >> >> 2010/2/5 Martin Koci <ma...@aura.cz>
> >> >>>
> >> >>> Hi,
> >> >>>
> >> >>> during  profiling YourKitProfiler always marks
> >> >>>
> >> >>>
> >> >>> org.apache.myfaces.resource.ClassLoaderResourceLoader.getLibraryVersion(String)
> >> >>> as hotspot - that method always takes 30--50% CPU time per one
> >> >>> request/response. Is it a known problem? I will provide more
> >> >>> information
> >> >>> later.
> >> >>>
> >> >>> Regards,
> >> >>>
> >> >>> Martin Kočí
> >> >>>
> >> >>>
> >> >>>
> >> >>>
> >> >>
> >> >
> >> >
> >>
> >>
> >>
> >> --
> >> Matthias Wessendorf
> >>
> >> blog: http://matthiaswessendorf.wordpress.com/
> >> sessions: http://www.slideshare.net/mwessendorf
> >> twitter: http://twitter.com/mwessendorf
> >
> >
> 
> 
>