[Anders Broman <a.broman@xxxxxxxxx>]

Gerasimos Dimitriadis skrev 2010-05-15 23:12:
> Hi,
>
> I did some benchmarking on the performance gains from the switch to
> binary search in the SANC and ISPC arrays, that I want to share with the
> list. The SANC array contains ~900 entries, while the 2 ISPC arrays
> (signalling point and operator names) contain ~5k entries each.
>
> For this experiment, a synthetic capture file of 50000 MTP3/SCCP
> messages was created. Each message is based on the following template,
> with the OPC and DPC being randomly chosen from values existing in the
> ISPC array. This means that the search always leads to a match, but
> since this list contains all PCs currently allocated by the ITU, this is
> going to be the case for actual traffic too.
>
> Message Transfer Part Level 3
>      Service information octet
>          00.. .... = Network indicator: International network (0x00)
>          ..00 .... = Spare: 0x00
>          .... 0011 = Service indicator: SCCP (0x03)
>      Routing label
>          .... .... .... .... ..11 1001 1110 0110 = DPC: 14822
>              Signalling Area Network Code (SANC): Chile (7-060)
>              Unique Signalling Point Name: ...
>              Signalling Point Operator Name: Compania de Telefonos de
> Chile - Mundo S.A.
>          .... 1000 0001 1100 00.. .... .... .... = OPC: 8304
>              Signalling Area Network Code (SANC): India (Republic of) (4-014)
>              Unique Signalling Point Name: ISC Chennai
>              Signalling Point Operator Name: M/s Dishnet Wireless Ltd
>          0011 .... .... .... .... .... .... .... = Signalling Link
> Selector: 3
> Signalling Connection Control Part
>      Message Type: Released (0x04)
>      Destination Local Reference: 0xffda05
>      Source Local Reference: 0x1001df
>      Release Cause: End user originated (0x00)
>      Pointer to Optional parameter: 0
>
> In each scenario (linear / binary search), tshark -V was run 3 times
> with the output redirected to /dev/null. The averages are provided
> below, showing that the performance improvements are substantial:
> Linear Search: real 6.302s - user 5.355s - sys 0.738s
> Binary Search: real 4.868s - user 4.004s - sys 0.697s
>
> Regards
> Gerasimos
>
>    
I'm sure the GSM/UMTS related dissectors would benefit especially if 
"index method" can be used. Asn2wrs
should perhaps be changed to use the new method. I just don't have the 
traces nor time to so  benchmarking.
Regards
Anders

> > http://anonsvn.wireshark.org/viewvc/viewvc.cgi?view=rev&revision=32822
> >
> > User: dimeg
> > Date: 2010/05/15 01:14 PM
> >
> > Log:
> >   Use binary search when scanning the SANC and ISPC lists; correct a couple of
> >   double entries in the ISPC lists.
> >
> > Directory: /trunk/epan/dissectors/
> >    Changes    Path             Action
> >    +9 -7      packet-q708.c    Modified
> >
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