Re: [xml] libxml2 performance

[Daniel Veillard <veillard redhat com>]

On Thu, May 30, 2002 at 11:41:31AM +0200, Peter Jacobi wrote:
Content-Description: Mail message body
> Hi Daniel, All,
>
> This may be a futile exercise in micro-optimization,
> but given over 7% time attributed to isolat1ToUTF8
> I've tried to improve that routine.
>
> > xmllint --noout --timing --repeat doc/libxml2-api.xml
> [...]
> >   7.71      1.58     0.32    12400    25.81    25.81  isolat1ToUTF8
> [...]
>
>
> The attached patch introduces a fast path for plain ASCII
> characters in the isolat1 input (up to 40% faster) with no
> penalty (even slightly faster) for all input chars in the upper
> half (and reasonable linear scaling between the extremes).
> It's the fastest I can get when not allowed to be slower on
> any input.
>
> Of course, for such small routines you are at the mercy
> of your compiler anyway, so it's not that clear what gcc
> and others will make of it.

  thanks, applied, but it seems to not change much:

before (yesterday's run):

xmllint --noout --timing --repeat doc/libxml2-api.xml

Each sample counts as 0.01 seconds.
  %   cumulative   self              self     total
 time   seconds   seconds    calls  us/call  us/call  name
 22.65      0.94     0.94  1167400     0.81     1.39  xmlParseAttValue
  7.71      1.26     0.32 18745300     0.02     0.02  xmlCurrentChar
  7.71      1.58     0.32    12400    25.81    25.81  isolat1ToUTF8
  5.78      1.82     0.24  3570200     0.07     0.07  xmlNextChar
  4.58      2.01     0.19  1167500     0.16     0.20  xmlFreeNodeList
  4.34      2.19     0.18   917400     0.20     0.44  xmlParseCharData
  3.86      2.35     0.16  5782622     0.03     0.03  xmlStrndup
  3.37      2.49     0.14  1167400     0.12     0.53  attribute
  2.89      2.61     0.12  1167400     0.10     0.10  xmlNewNsPropEatName
  2.89      2.73     0.12   675000     0.18     1.54  startElement

after:

Each sample counts as 0.01 seconds.
  %   cumulative   self              self     total
 time   seconds   seconds    calls  us/call  us/call  name
 23.50      1.10     1.10  1167400     0.94     1.55  xmlParseAttValue
  8.33      1.49     0.39 18745300     0.02     0.02  xmlCurrentChar
  6.84      1.81     0.32  1167500     0.27     0.32  xmlFreeNodeList
  6.84      2.13     0.32    12400    25.81    25.81  isolat1ToUTF8
  4.70      2.35     0.22   917400     0.24     0.48  xmlParseCharData
  4.49      2.56     0.21   675000     0.31     5.07  xmlParseStartTag
  3.63      2.73     0.17   675000     0.25     1.52  startElement
  3.42      2.89     0.16  5782622     0.03     0.03  xmlStrndup
  3.21      3.04     0.15  1167400     0.13     0.23  xmlStringGetNodeList
  2.78      3.17     0.13  1349900     0.10     0.10  xmlSearchNs
  
 I'm surprized by the overall changes, well maybe I can't trust gprof much ...

Daniel

-- 
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veillard redhat com  | libxml GNOME XML XSLT toolkit  http://xmlsoft.org/
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