Re: [docbook-apps] gentext.template eats 1/3 of CPU

[Stefan Kost <ensonic@hora-obscura.de>]

hi,

Bob Stayton wrote:
> Hi Stefan,
> Pretty much every title and xref, as well as any other generated text,
> is processed by the gentext machinery. That's how DocBook handles
> content in the 65 supported languages, including content with a mix of
> languages.  And every title is usually processed more than once, in
> its location and in the TOC.  I think it would be difficult to bypass
> the gentext machinery, since it is part of the architecture of the
> stylesheets.
>
> I don't think any of the developers would disagree if I said that the
> DocBook XSL stylesheets are not optimized for speed, but for
> supporting the large array of features and options, as well as
> supporting customization.  I had a client who needed speed and did not
> need all the features, options, and customizations, so I wrote a new
> set of XSL templates that did exactly what they wanted for the
> elements they were using, and no more.  They were fast.  And they were
> simple enough for them to maintain.
>
thanks for the reply. Thanks to my profiler I could make several
optimizations that don't make the stylesheets worse or loose on
functionality. Right now I have them in my customization layer. Not sure
if anyone would be interested in patches.

Main problem with gentext right now is also that it does not remember
any lookups (memoization in functional languages). Dunno if such thing
is doable in xslt. I could certainly see the same lookups several time.

What I am now looking into is writing a xslt pre processor, that reads
the xsl + parameters, resolved includes + imports, kicks unused
templates, replaces statics and so on. Then that pre processed
stylesheet should be faster. Lots of work, lets see :)

Stefan


> Bob Stayton
> Sagehill Enterprises
> bobs@sagehill.net
>
>
> ----- Original Message ----- From: "Stefan Kost"
> <ensonic@hora-obscura.de>
> To: <docbook-apps@lists.oasis-open.org>
> Sent: Monday, March 08, 2010 6:29 AM
> Subject: [docbook-apps] gentext.template eats 1/3 of CPU
>
>
>> hi,
>>
>> I have a first version of a callgraph profiler for libxml/libxslt
>> (https://bugzilla.gnome.org/show_bug.cgi?id=612186). With this I looked
>> at profiles for applying the docbook stylesheets. These are the topmost
>> entries:
>>
>> index % time    self  children    called     name
>>                0.043    0.380   1947/3287     
>> gentext.template.exists [4]
>>                0.002    0.397    234/3287      *[object.title.template]
>> [49]
>>                0.380    0.380   1071/3287      gentext.template [0]
>>                0.000    0.397     17/3287
>> part[object.title.template] [90]
>>                0.000    0.397     18/3287
>> chapter[object.title.template] [102]
>> [0]    33.26    0.380    0.380   3287     gentext.template [0]
>>                0.380    0.380   1071/1071      gentext.template [0]
>> -----------------------------------------------
>>                0.009    0.149    786/3967      *[find.chunks] [19]
>>                0.010    0.154    738/3967      href.target.uri [18]
>>                0.012    0.241    754/3967      *[chunk-filename] [16]
>>                0.056    0.202   1638/3967
>> *[recursive-chunk-filename] [2]
>>                0.001    0.136     35/3967      in.other.chunk [76]
>>                0.001    0.173     16/3967      process-chunk [55]
>> [1]    11.84    0.135    0.000   3967     chunk [1]
>> -----------------------------------------------
>>
>> lines with [x] in begin are the templates. lines above the callers,
>> lines below the callees. Any idea how to make gentext.template less
>> slow? Or make it called less often. There sees to be many:
>>  match="*" mode="object.title.template"
>> and
>>  match="*" mode="object.title.markup"
>> leading to it, but I can't see any template that uses e.g.
>> mode="object.title.markup"? Any ideas?
>>
>> Stefan
>>
>>
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>>
>
>
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