[fpc-pascal] TPersistent overhead

Michael Van Canneyt michael at freepascal.org
Sat Mar 26 07:58:33 CET 2016

On Sat, 26 Mar 2016, Ryan Joseph wrote:

> What are all the performance costs associated with subclassing TPersistent
> for RTTI information?  I want to use this in some classes but
> unfortunately the way my code is written I need to basically make all my
> classes descend from TPersistent, even classes that don’t need RTTI
> information.

There is none.

> I noticed in my project there is an extra .6 seconds of compile time when
> I make the changes but are there any other performance costs to consider
> during runt time or otherwise?  I could deal with .6 seconds at compile
> even though 95% of that is waste but runtime is another story.

The overhead is most likely due to writing of RTTI tables.
They are static, and add to the size of the binary, but do not incur speed


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