[fpc-pascal]Execution speed

Mark Emerson ChiefAngel at angelbase.com
Fri Jan 24 16:39:26 CET 2003

Now that the list seems to be working again...I'll try posting this again:

I am wondering why our new PC is not executing our fpc-compiled program
very much faster than the old one. It was really quite a disappointment:

Old PC: Laptop, Intel PII, 300 MHz, 64 MB. Execution times: 8:30, 2:30 (min:sec)

New PC: Desktop, AMD Duron, 1.6 GHz, 128 MB. Execution times: 5:15, 1:15

The new PC ought to be 5 times faster (1600 MHz / 300 MHz, right? Of
course the speed of the memory is also a factor) but it's not even twice
as fast.

The execution time pairs are determined from three time stamps that
occur during one run of the program. The sequence is as follows:

* Stamp 1
-Initialize (5-10 secs reading/processing from HD)
-Process 1 (5-9 mins)
* Stamp 2
-Process 2 (1-3 mins)
* Stamp 3

Both machines are running Win98 Second Edition (could Windows 98 be
preventing the faster machine from running at full capacity? Or perhaps
it's because fpc runs in a DOS window, and the DOS mode is forcing it to
run slow?)

The program is very processor intensive. Only about 4MB of memory space
is used.

During runtime, we are doing less than 400 kb of read/write combined to
the HD. We put about 10 lines of text on the DOS screen to show
progress. So I can't imagine the I/O could be slowing us down.

I tried compiling with the two different target platforms, but it didn't
make a difference. Stackchecking is on, but it was on on both computers.

I also tried a few different bios settings (the computer has ready-made
bios configurations for "Optimal" and "Best Performance" (?) as well as
the factory default I started with.) But the compile times were the same
regardless of the bios settings.

Any thoughts?


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