Florian Klaempfl schrieb:
Adrian Veith wrote:
Hi,
two days ago i posted a comment about my experiences porting our
database server to fpc. yesterday i tried to figure out where the speed
differences between delphi and fpc come from. At the moment i stuck a
little bit, because the results i get don't make any sense at the moment
to me.
Anyway i dropped over another problem, which might be part of the cause
of my problems. I tried to create a test base for my investigations and
created a function NumberToText which converts an integer to written
text (like NumberToText(1234) -> "one thousand two hundred thirty
four"). When I filled my database with these generated strings I found
some significant speed differences between delphi and fpc (over factor
10), which made me curious. According to your comments about my first
posting, i suspected the Memory Manager and created three different
versions of this NumberToText function and three test loops which each
calls the according NumberToText function for 0..999999. Here are the
results for fpc and delphi (w and w/o FastMM4)
Test1 uses "optimized" string concatention which avoids heap fragmentation
Did you try/have an unoptimized version? FPC doesn't need these
optimizations, I fear they hurt only.
the example includes two "optimized" and one unoptimized version. the
first "optimized" version is the fasted for fpc 2.0.2 (about 2 times)
but in delphi it has no effect.
But you are completely right for the fpc 2.1.1 version which I just
tried out - and I am very pleased. Here are the results:
Test1:
fpc: 3.1 sec - factor = 1.34
delphi (standard MM): 3.1 sec - factor = 1.34
delphi (FastMM4): 2.3 sec - factor = 1
Test2:
fpc: 2.8 sec - factor = 1.47
delphi (standard MM): 2.9 sec - factor = 1.52
delphi (FastMM4): 1.9 sec - factor = 1
Test3:
fpc: 2.5 sec - factor = 1,19
delphi (standard MM): 3.4 sec - factor = 1.61
delphi (FastMM4): 2.1 sec - factor = 1
the increase in speed is remarkable !!!
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