>
>
>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.
>
In unmodified FOP, input from the source FO document occurs entirely at
the beginning of the FOP run, and output entirely at the end. Therefore,
the largest part of FOP processing occurs entirely in-memory and is
therefore CPU bound. If you run 30 CPU bound threads concurrently on a
machine with less than 30 CPUs then you are going to get degraded
performance.
When you say 6, 30 and 12 "fold", I assume you mean times? AFAIK,
processing time on a single CPU machine with a CPU bound thread running
with 29 other concurrent CPU bound threads *should* take 30 times
longer, because it's executing 30x the instructions. If the XSLT and the
formatting are doing I/O then these parts of the system will benefit
from threading because the JVM can make progress during IO waits. I'm
actually surprised that the numbers aren't much higher, but perhaps you
have SMP.
Anyway, I'm not sure if my analysis is entirely correct here but none of
this seems particularly surprising to me, and doesn't indicate any
problems with FOP processing per se.
Of course there is a lot I don't know about FOP so maybe someone call
explain this to me.
Regards
Mark
>
>
>The data seem to point to contention problems as was pointed out
>yesterday.
>
>>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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