On 2010-10-19 19:38, Alexander Klenin wrote:
On Wed, Oct 20, 2010 at 01:45, Michael Van Canneyt
<mich...@freepascal.org> wrote:
If you need more convincing: the contnrs unit contains 2 hash classes.
one based on ansistrings, one with pchars and shortstrings. The pchar
version is easily 20% faster. It comes from the compiler code and was
written specially by Peter Vreman.
Try and improve that class with ansistrings. If you succeed, only then we
can start making a case for using them in the compiler.
Ok, I went ahead and have taken look at the code.
I assume you speak about TFPHashList vs TFPCustomHashTable.
The classes are not really comparable, because they use quite
different internal data structures.
So instead I converted TFPHashList list to use ansistrings.
Benchmarking included 3*10^6 calls to Add and Find methods
with the arguments of various lengths.
Average string length 5 characters:
ShortString: 1.15 s
AnsiString: 1.56 s
Average string length 45 characters:
ShortString: 12.0 s
AnsiString: 3.2 s
I agree that the first case is more relevant for the compiler,
but still you can see that ShortStrings are clearly not always faster
Just curious: Would you, by any chance, have a figure for this:
In a (self) compile operation, how many times are either of these these
routines called?
--
Cheers,
Adem
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