Hi Carsten,
Thanks for your help mate. I'll check out the changes you made. :-)
Cheers,
Marcus
On Mon, 20 Aug 2001, Carsten Ziegeler wrote:
> I just updated the logic a little bit, the threads are now
> only blocked (synchronized) when no sitemap is available.
>
> This new code is a little bit confusion but it should work.
>
> Carsten
>
> > -----Ursprüngliche Nachricht-----
> > Von: Morrison, John [mailto:[EMAIL PROTECTED]]
> > Gesendet: Montag, 20. August 2001 14:05
> > An: '[EMAIL PROTECTED]'
> > Betreff: RE: [C2] sitemap creation threading issue ?
> >
> >
> > Yeah, and only on the huge box :(
> >
> > I've a tiddly little development server which is smaller than my
> > dev box but
> > is under my control and a whacking huge 'stage' set of machines. I'm
> > getting better performance from my dev boxes than a
> > multi-processor which a
> > gig or so of memory!
> >
> > > -----Original Message-----
> > > From: Carsten Ziegeler [mailto:[EMAIL PROTECTED]]
> > > Sent: Monday, 20 August 2001 1:03 pm
> > > To: [EMAIL PROTECTED]
> > > Subject: AW: [C2] sitemap creation threading issue ?
> > >
> > >
> > > Hi John,
> > >
> > > do you mean 5 seconds or 5 milliseconds?
> > > I fear you mean seconds, right?
> > >
> > > Carsten
> > >
> > >
> > >
> > > > -----Ursprüngliche Nachricht-----
> > > > Von: Morrison, John [mailto:[EMAIL PROTECTED]]
> > > > Gesendet: Montag, 20. August 2001 13:47
> > > > An: '[EMAIL PROTECTED]'
> > > > Betreff: RE: [C2] sitemap creation threading issue ?
> > > >
> > > >
> > > > Hi all, esp Marcus,
> > > >
> > > > I too have been running Load tests, I also noticed that
> > > 'something' was
> > > > happening regularly to slow the response. I hadn't gotten round
> > > > to checking
> > > > the code though (the testing machines are isolated - 0 access
> > > > from/to my dev
> > > > station).
> > > >
> > > > I saw your patch and rejoiced ;) but it's taken the
> > > response of some of my
> > > > pages from a couple of hundred milliseconds to over 5! I've not
> > > > yet looked
> > > > at _what_ your patch did, but have you seen a similar
> > > increase in time?
> > > >
> > > > J.
> > > >
> > > > > -----Original Message-----
> > > > > From: Carsten Ziegeler [mailto:[EMAIL PROTECTED]]
> > > > > Sent: Monday, 20 August 2001 7:57 am
> > > > > To: [EMAIL PROTECTED]
> > > > > Subject: AW: [C2] sitemap creation threading issue ?
> > > > >
> > > > >
> > > > > Hi Marcus,
> > > > >
> > > > > thanks for your patch. I applied it, please cross check :-)
> > > > >
> > > > > Carsten
> > > > >
> > > > > > -----Ursprungliche Nachricht-----
> > > > > > Von: Marcus Crafter [mailto:[EMAIL PROTECTED]]
> > > > > > Gesendet: Samstag, 18. August 2001 22:41
> > > > > > An: Cocoon Developers Mailing List
> > > > > > Betreff: [C2] sitemap creation threading issue ?
> > > > > >
> > > > > >
> > > > > > Hi *,
> > > > > >
> > > > > > Hope all is well.
> > > > > >
> > > > > > Michael and I have spent the day testing our C2
> > > application with
> > > > > > LoadRunner and have potentially uncovered a threading
> > > > > problem during
> > > > > > sitemap creation.
> > > > > >
> > > > > > We're not experts with the code but from our
> > > understanding the
> > > > > > following is happening, please let us know if we are
> > > > > right/wrong:
> > > > > >
> > > > > > There seems to be a problem with the getHandler()
> > > > > method, located in
> > > > > > the sitemap Manager class (line 154).
> > > getHandler() attempts
> > > > > > to access a
> > > > > > sitemap handler object for each request for
> > > processing. If
> > > > > > the handler
> > > > > > object is not available it creates one, causing the
> > > > > sitemap to be
> > > > > > generated.
> > > > > >
> > > > > > We've noticed under load, that many handler objects are
> > > > > created for
> > > > > > the same sitemap. This is because getHandler() does not
> > > > > protect the
> > > > > > following lines:
> > > > > >
> > > > > > Handler sitemapHandler =
> > > (Handler)sitemaps.get(source);
> > > > > >
> > > > > > and
> > > > > >
> > > > > > sitemaps.put(source, sitemapHandler);
> > > > > >
> > > > > > as a critical area.
> > > > > >
> > > > > > If multiple concurrent threads pass through
> > > > > getHandler() which are
> > > > > > requests for resources from the same sitemap,
> > > the first line
> > > > > > above will return null multiple times causing the same
> > > > > sitemap to be
> > > > > > compiled several times, each by individual
> > > Handler objects.
> > > > > >
> > > > > > This happens because sitemaps.put() executes after each
> > > > > > sitemap handler
> > > > > > object is created (which can take time for
> > > large sitemaps),
> > > > > > and cannot
> > > > > > prevent other incoming threads from waiting until it
> > > > > adds the newly
> > > > > > created handler object into the 'sitemaps' hashmap.
> > > > > >
> > > > > > When we synchronized the getHandler method to
> > > protect the
> > > > > > getting/setting of the sitemaps hashmap, we saw
> > > that the sitemap
> > > > > > handler object was created only once, and that
> > > the application
> > > > > > performed much better under load. Previously the same
> > > > > > sitemap handler
> > > > > > object was created as many times as we had
> > > simultaneous threads
> > > > > > make requests.
> > > > > >
> > > > > > Attached is a diff of the change we made. There might
> > > > > be a better
> > > > > > solution as the Handler class seems to be built to
> > > > > handle this, it's
> > > > > > just that the allocation of a new Handler objects per
> > > > > > sitemap, defeats
> > > > > > it's internal multi-thread logic.
> > > > > >
> > > > > > Any comments/thoughts/suggestions ?
> > > > > >
> > > > > > Cheers,
> > > > > >
> > > > > > Marcus
> > > > > >
> > > > > > --
> > > > > > .....
> > > > > > ,,$$$$$$$$$, Marcus Crafter
> > > > > > ;$' '$$$$: Computer Systems Engineer
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