Issue 120575 - [From Symphony] optimize a comparing operation from 'memcmp' to 'hash compare' to improve xls loading performance
Summary: [From Symphony] optimize a comparing operation from 'memcmp' to 'hash compare...
Status: CLOSED FIXED
Alias: None
Product: performance
Classification: Code
Component: code (show other issues)
Version: AOO 3.4.0
Hardware: All All
: P3 Normal (vote)
Target Milestone: 4.0.0
Assignee: AOO issues mailing list
QA Contact:
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2012-08-15 02:53 UTC by lizh.fee
Modified: 2016-04-09 10:40 UTC (History)
2 users (show)

See Also:
Issue Type: ENHANCEMENT
Latest Confirmation in: ---
Developer Difficulty: ---

Attachments
patch for improving xls loading performance (9.83 KB, patch)
2012-08-24 05:36 UTC, lizh.fee 		lizh.fee: review?
Details | Diff
sample (108.00 KB, application/vnd.ms-excel)
2012-08-24 06:00 UTC, lizh.fee 		no flags Details
Add an attachment (proposed patch, testcase, etc.)

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Description lizh.fee 2012-08-15 02:53:52 UTC 

    


    


      



        
          Comment 1
        

        
          lizh.fee

        

        
        

        
          2012-08-24 05:36:09 UTC
        

      






Created attachment 79115 [details]
patch for improving xls loading performance

    


    


      



        
          Comment 2
        

        
          lizh.fee

        

        
        

        
          2012-08-24 05:59:33 UTC
        

      






Root cause: 
in xls loading procedure, ScPatternAttr::operator== occupies too much time, in this function, two sfxitemset are compared by memcmp(...), this is a time consuming operation.

Resolution:
Instead of memcmp(...), two sfxitemset can be compared 'quickly' by the hashkey only. And a function SfxItemSet::QuickCompare( SfxItemSet & rCmp) instead of EqualPatternSets(...).

Test result:
In ScPatternAttr::operator==, SfxItemSet::QuickCompare( SfxItemSet & rCmp) will be called 3141717 times, including 3114837 times only comparing hash key and directly return, memcmp(...). will be called 26880 times.

    


    


      



        
          Comment 3
        

        
          lizh.fee

        

        
        

        
          2012-08-24 06:00:28 UTC
        

      






Created attachment 79117 [details]
sample

    


    


      



        
          Comment 4
        

        
          lizh.fee

        

        
        

        
          2012-08-24 06:43:58 UTC
        

      






following is test result for sample file (manual test), about 10% improvement. 
old:  4.31 4.38 4.37 4.44 4.31 4.34 4.41 4.40 4.47 4.50     avg:4.40 
new:  3.90 3.93 3.78 3.75 3.75 3.85 3.84 3.87 4.00 4.00     avg:3.87

    


    


      



        
          Comment 5
        

        
          SVN Robot

        

        
        

        
          2012-09-14 08:04:15 UTC
        

      






"leiw" committed SVN revision 1384677 into trunk:
#i120575 optimize a comparing operation from 'memcmp' to 'hash compare' to im...

    


    


      



        
          Comment 6
        

        
          Wang Lei

        

        
        

        
          2012-09-14 08:07:54 UTC
        

      






Submit in revision 1384677, thanks for your patch

    


    


      



        
          Comment 7
        

        
          Marcus

        

        
        

        
          2016-04-09 10:40:01 UTC
        

      






fixed in 4.0.0