Calc/Performance/Specific Bottlenecks

Specific bottlenecks to be worked on, identified using tools such as valgrind --tool=callgrind.

The Zaske case

Content relocated to Calc/Performance/Zaske, section preserved for external references linking here.

The Ou case

Loading a large plain data file takes very long.

References:

• George Ou's blog entry
• The test case file (.sxc)
• Same data, but zip'ed Excel-XML

Findings:

• source/filter/xml/xmlsubti.cxx
  • 38% of time spent in ScMyTables::NewColumn() because of replicated use of aTableVec[nTableCount - 1] (vector::operator[])
    Note: percentage may be off due to compilation without optimization to obtain exact line numbers that may result in STLport's vector methods being differently compiled.
    • proposed fix: should obtain the pointer once instead.
  • Similar for other places where aTableVec[xxx] is used.

• TODO: Check all ScMyTables::.*() and ScMyTableData::.*()
  • Especially for 63342857 calls to AddColumn() and NewColumn() that result in 1168654944 calls to operator[] ...
  • 63081776 calls to AddColumn() originate from ScXMLTableRowCellContext::EndElement()
  • Those are highly suspicious and seem to indicate that too many temporary elements are created for empty columns/cells (needs verification).

Sorting values within functions

Content relocated to Calc/Performance/sorting_values_within_functions, section preserved for external references linking here.

Querying data within functions

An internal customer's document (sorry, can't publish) doing lookup queries that don't fit into the current caching strategy.

Findings:

• 8% in 51613353 calls to com::sun::star::i18n::casefolding::getNextChar() via
  • 39696595 calls to utl::TransliterationWrapper::isEqual() via
    • ScTable::ValidQuery() via
      • 8888 calls to ScQueryCellIterator::GetThis() via
        • lcl_LookupQuery()

• 5% in ScTableValidQuery() most in String() and ~String() of aCellStr

• 200873636 calls to com::sun::star::i18n::casefolding::getNextChar() via
  • 33173401 calls to com::sun::star::i18n::Transliteration_caseignore::compare()

• 5% in com::sun::star::i18n::oneToOneMappingWithFlag::find()
  • Replicated mpIndex[high] access, might be better using temporary pointer.

• 5% in com::sun::star::i18n::casefolding::getValue()

• 58% overall in ScTable::ValidQuery() and below
  • TODO: Cache results of ValidQuery()? Similar to ScLookupCache?

• 11% overall in 27341713 calls to ScBroadcastAreaSlot::StartListeningArea() and below, of which 10% are in ::std::set::insert() and below.
  • TODO: refactor implementation of broadcast slots.