Re: How to improve LUA dissector performance?

[Jeff Morriss <jeff.morriss.ws () gmail com>]

On Mon, Apr 15, 2019 at 9:04 AM David Aldrich <david.aldrich.ntml () gmail com>
wrote:

> I haven't seen any answers to my question below. Any thoughts please?
>
> Hi
> > I have written a LUA dissector that analyses large packets that consist
> > of control information and  IQ data (complex numbers).  Until recently I
> > displayed the IQ data as a string and performance was fine. However, I now
> > dissect and display each IQ value and the user has complained of very slow
> > performance when analysing a large capture set of packets.
> >
> > I imagined that dissection of the IQ data would only occur when the tree
> > was expanded to display that data.  The reported slowness suggests that the
> > data for all packets is always dissected regardless of whether or not the
> > data is viewed. Is that correct?
> >
> > Apart from re-coding as a C++ dissector (a lot of work) how could I
> > optimise the current LUA code?
> >
> > Could I add a switch to control whether or not IQ data is dissected?
You could try avoiding doing dissection work if the tree is NULL; I'm
assuming that the tree is actually NULL in Lua (I don't know).

In C we've decided checking for tree==NULL isn't worth the code
complication; maybe it could help with a slower language like Lua?

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