[fpc-devel] FPC/Lazarus Rebuild performance

Florian Klämpfl florian at freepascal.org
Sun Sep 12 18:27:48 CEST 2010

Am 12.09.2010 18:24, schrieb Dimitri Smits:
> ----- "Marco van de Voort" <marcov at stack.nl> schreef:
>> I partially agree with you in the fact that the exact reasons are
>> not known.
>> I'm no expert on profiling the compiler, but if I read the various 
>> threads over the years I see defensive and conflicting statements:
>> In discussions with Hans, it is said that I/O is not a factor,
>> since after one run everything is cached anyway, and then in this
>> thread I/O is to blame for a huge difference in speed.
> that may be the case for reading, not necessarily for the files being
> written. in ppu.pas, everything you "put" results in a blockwrite of
> x bytes. Wouldn't a cached memory stream be better, not resulting in
> those int21h calls or windows equivalent calls?

The ppu writer uses a buffer of 16 kB which is enough. Believe me, it's
no so simple as just use a memory stream to improve performance. If it's
the case, we would have done it for years.

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