Re: [xml] Thread safety

[Daniel Veillard <veillard redhat com>]

On Thu, Jul 03, 2003 at 08:57:40AM -0700, Jerome Pesenti wrote:
> Turning on thread safety in libxml seems to have a big
> perfomance cost when doing XSL transformations.
>
> Here is a typical example:
>
> 22ms Using libxml 20507 (--without-threads), libxslt
> 10030 and libexslt 719
> 37ms Using libxml 20507 (--with-threads, libxslt 10030
> and libexslt 719
> 30ms Using libxml 20430, libxslt 10024 and libexslt
> 715
>
> That is a 70% increase in running time (note the nice
> 30% improvement between 2.4.30/1.2.4 and 2.5.7/1.3.0)
> which I can consistenly reproduce with different
> XML/XSL.
>
> Is there any way to go around this?

  make sure your memory allocator for threaded and non-threaded
operations is as fast. If you're on linux and using a not very recent
(i.e. something like RH9 with NPTL) then you're hitting the old
-lpthread memory allocator which had the kind of perf problem you
report. You don't report your OS setup but I suspect you have a not
very recent Linux setup ...

> Other question: is --with-threads required for 
> thread safety when running different transformations
> with different XML and XSL and the same global
> options?

  probably not but --with-threads introduce a level of
confidence I don't have without it. It may depend how your
application is coded...

Daniel

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