[fpc-devel] Messages overhead

[Michael Van Canneyt]

On Thu, 15 Jul 2010, Graeme Geldenhuys wrote:

> Op 2010-07-14 17:17, Daniël Mantione het geskryf:
>>> IMO compiler messages slow down compilation a lot.
>>
>> How do you know this, did you benchmark or is it just your opinion?
>
> A few weeks ago, I benchmarked that too (well similar). I did a comparison
> between Kylix 3 and FPC 2.4.x. When I disabled all compiler message output,
> FPC compiled the test apps a bit faster that with -va parameter. It wasn't
> an exhaustive test by any means, but there was a difference. So I would
> imagine Hans has a point, that removing any calls to message output would
> reduce compilation even more.

I think that it is more the actual syscalls to write info which make the
difference than the preparation of the syscall. If you wrote output to the
terminal, then that is an additional slowing-down factor.

The only way to test the impact of message preparation is to uncomment the 
actual write call, compile with -va and then compile again (clean) with -v0.

Michael.