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From robert engels <reng...@ix.netcom.com>
Subject Re: [jira] Created: (LUCENE-1172) Small speedups to DocumentsWriter
Date Sun, 10 Feb 2008 20:18:37 GMT
As a followup, I think when people report timing numbers they should  
be done on a *nix, so that you can report, real, user, system and  
wait for io times.

Even with this, there are other issues (JVM compilation times, GC  
times), etc. that will affect the relevancy of the timings.


On Feb 10, 2008, at 1:37 PM, Michael McCandless wrote:

>
> Yonik Seeley wrote:
>
>> I wonder how well a single generic quickSort(Object[] arr, int low,
>> int high) would perform vs the type-specific ones?  I guess the main
>> overhead would be a cast from Object to the specific class to do the
>> compare?  Too bad Java doesn't have true generics/templates.
>
>
> OK I tested this.
>
> Starting from the patch on LUCENE-1172, which has 3 quickSort methods
> (one per type), I created a single quickSort method on Object[] that
> takes a Comparator, and made 3 Comparators instead.
>
> Mac OS X 10.4 (JVM 1.5):
>
>     original patch --> 247.1
>   simplified patch --> 254.9 (3.2% slower)
>
> Windows Server 2003 R64 (JVM 1.6):
>
>     original patch --> 440.6
>   simplified patch --> 452.7 (2.7% slower)
>
> The times are best in 10 runs.  I'm running all tests with these JVM
> args:
>
>   -Xms1024M -Xmx1024M -Xbatch -server
>
> I think this is a big enough difference in performance that it's
> worth keeping 3 separate quickSorts in DocumentsWriter.
>
> Mike
>
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