On 18 Jul 2001 04:28:25 -0700, Christopher R. Maden wrote:
> At 03:25 18-07-2001, Weiqi Gao wrote:
> >We did some playing around with a simple FOP servlet that does
> >XHTML->XSL-FO->PDF using Xalan and FOP and come away with the following
> >findings:
> >
> >1. It uses quite a bit of memory.  While running around 20-30 concurrent
> >users, each generating a set of four PDFs ranging from 2 to 5 pages five
> >times each, the servlet engine memory usage is about 110MB.
> >
> >2. It uses quite a bit of CPU.  While running the above test, the CPU is
> >about 50% with 10 users, 70% with 20 users, and over 80% with 30 users.
> >
> >3. It takes quite a bit of time to do the generation.  The minimum
> >generation time for the four documents are from 1 to 4 seconds (the 4
> >seconds one is 5 pages with 13 tables with various cell colors and
> >border styles).  In the 30 user test, the average time are from 20 to 40
> >seconds, and maximum well over 2 minutes.
> How much of that load is from Xalan and how much from FOP?

I need to separate the two, but my gut feeling is that FOP is dominating
the time and CPU.  In my previous experiments, XSLT time is only 1/10's
of the total time.

I just run 30 threads of my earlier chapter 15 allelements example on my
home machine and noticed that compared to a single thread run, time
spent on XSLT increased roughly 6 fold, time spent on build FO tree
increased 30 fold, formating 12 fold.  Context switches are at 60000 per
second level while in FOP, compared to 4000 per second while in Xalan.

The data seem to point to contention problems as was pointed out

> It might be instructive to construct a similar applet that uses Xalan to do 
> XHTML->XSL-FO, and serve those FOs (labeled as application/xml) to the 
> browser.  If a significant portion of the load is due to Xalan, a reduction 
> might be possible by using a different XSLT engine such as SAXON.  (SAXON 
> is also more compliant than Xalan.)
> -Chris
> -- 
> Christopher R. Maden, XML Consultant
> DTDs/schemas - conversion - ebooks - publishing - Web - B2B - training
> <URL: http://crism.maden.org/consulting/ >
> PGP Fingerprint: BBA6 4085 DED0 E176 D6D4  5DFC AC52 F825 AFEC 58DA
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Weiqi Gao

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