[TCLCORE] Re: Hintermayer's string allocation patch

[Eric M. <er...@aj...>]

On Thu, 31 Aug 2000, Donald G Porter wrote:

> It's worth considering the asymptotics, too.  As others have
> observed, the O(N**2) behavior of the new algorithm will bite when
> the "1000" in these benchmarks grows to 10000, 100000, 1000000, ...

Yes, the performance will be bad, but is it better to have a badly
performing system that can allocate all of memory, or a really fast system
that cannot?  This seems like a no-brainer to me:  I can write a program
to give you the wrong answer to any question, and it can be really,
really fast... but it still gives you the wrong answer.

> Another concern is the platform-specific tuning necessary to choose
> good values for TCL_GROWTH_LARGE_STRING and TCL_GROWTH_MIN_ALLOC.
> How will good values for these be determined over all the platforms
> Tcl runs on and will run on over the next, say, 5 years?

The same way that we pick any values like these:  take something that
seems reasonable and run with it.  If in 5 years it isn't working, adjust
it.  As I consider these factors again, values of 4MB/4KB (respectively)
seem more reasonable to me.

Again, I urge everybody not to get hung up on the performance issue and
consider the memory issue:  without _some_ kind of change, Tcl simply
cannot use all available memory.  This modification is simple, it works,
and it is already implemented.  I have not yet seen any other proposal
that can say the same.

   Eric Melski                            The Other Tcl Guy
   ericm at ajubasolutions.com            Ajuba Solutions

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