Mail Archives: djgpp/1999/06/20/03:47:20
On Thu, 17 Jun 1999, Rolf Campbell wrote:
> I suspect it's the windows DPMI stuff, and in general, all vm interupts.
> Process creation/memory allocation (behind sbrk)/interupt
> enabling/disabling,.... it all adds up.
I would like to see some hard evidence before I believe in this. Most
of the jobs I was talking about don't do anything of the above too
much. They don't launch too many sub-programs, they don't call sbrk
too much, and they certainly don't enable/disable interrupts.
> When I ran it in real DOS with the same input file, it
> always ended up taking the exact same amount of time. Under W95, not only
> was it running at 10-30% slower, but it would vary greatly from one moment to
> another. I would run it twice in a row, and one would be 9.8 seconds, the
> other would be 7.6 seconds.
This probably means that your DOS configuration didn't have any disk
cache, or its cache was too small. I always get shorter times when I
run a disk-bound program the second time, both in DOS and in Windows.
Sometimes the difference is 10-fold, it really depends how large is
the file that the program reads.
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