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Unexpected slowdowns on AMD k6-2-400

Greetings!!

I wrote a small program that calculates various fractal functions and
displays them on-screen (this involves a lot of floating point
operations).  It was developed a couple of months ago, on my trusty
Intel Pentium 166.

Recently I have upgraded to an AMD k6-2-400 (and changed the OS to
windows NT).  When I've tried running the program today I have
experienced strange slowdowns:  for some time it runs with normal speed,
then slows down A LOT (the speed drops to a tenth of what it was) and
then the computation speeds back up again.  When I was testing this
program on the P166 the computation speeds were pretty much the same all
the time.

Any ideas about what can be causing it and what can be done?

Also, on a (probably) unrelated note:  I am surprised that I did not get
the famed RTE 200 bug.  All of the programs I wrote that use the CRT
module still work.  Why would that be (not that I'm complaining or
anything)?

Nikita.

 

Re:Unexpected slowdowns on AMD k6-2-400


Quote
Nikita Synytskyy wrote:

[...]

Quote
> Recently I have upgraded to an AMD k6-2-400 (and changed the OS to
> windows NT).  When I've tried running the program today I have
> experienced strange slowdowns:  for some time it runs with normal speed,
> then slows down A LOT (the speed drops to a tenth of what it was) and
> then the computation speeds back up again.  When I was testing this
> program on the P166 the computation speeds were pretty much the same all
> the time.

> Any ideas about what can be causing it and what can be done?

[...]

Quote
> Nikita.

  Hi Nikita

  Are you using writeln to display the results?

  I found  a  similar  thing when counting the  number  of  cpu cycles
  needed to write a string to the display.

  The first  five  passes  took several hundred  cycles  to  write the
  string (I forget exactly how many.)

  The fifth  and  subsequent  passes  took  something  like  5,000 cpu
  cycles. This  behavior  repeated without fail each  time  I  ran the
  program. I could find no reason for it.

  This was on a P100. I haven't tried it on a AMD K6-266.

Best Regards,

Michael R. Monett
mailto:a...@csolve.net

Re:Unexpected slowdowns on AMD k6-2-400


Quote

>   Hi Nikita

>   Are you using writeln to display the results?

No.  The result is a picture drawn using good old egavga.bgi

Quote

>   I found  a  similar  thing when counting the  number  of  cpu cycles
>   needed to write a string to the display.

I think I have solved my own problem.  I tried running the program again
yesterday.  AFter about 10 seconds running, it slowed down.  I
accidentally moved the mouse--and, lo and behold, it sped right up
again.  My guess is that Windows NT reduces the processor time allocated
to the program after a certain period without keyboard input (although
in my case this certain period is way too short).

Nikita.

Re:Unexpected slowdowns on AMD k6-2-400


In article <37D46A7C.1731...@mondenet.com>,
  Nikita Synytskyy <nik...@mondenet.com> wrote:

Quote
> Greetings!!

> I wrote a small program that calculates various fractal functions and
> displays them on-screen (this involves a lot of floating point
> operations).  It was developed a couple of months ago, on my trusty
> Intel Pentium 166.

> Recently I have upgraded to an AMD k6-2-400 (and changed the OS to
> windows NT).

That's your problem! For some reason NT reduces time given to a DOS box
after a few seconds. Pressing a key will get it running again. I've had
the same problem with big sorts. (I cannot use M$ Sort, as it cannot
handle big files - correction, it may be able to handle them, but it is
way to sloooooooooooooooooooow)

Quote
> When I've tried running the program today I have
> experienced strange slowdowns:  for some time it runs with normal
> speed,
> then slows down A LOT (the speed drops to a tenth of what it was) and
> then the computation speeds back up again.  When I was testing this
> program on the P166 the computation speeds were pretty much the same
> all the time.

> Any ideas about what can be causing it and what can be done?

> Also, on a (probably) unrelated note:  I am surprised that I did not
> get
> the famed RTE 200 bug.  All of the programs I wrote that use the CRT
> module still work.  Why would that be (not that I'm complaining or
> anything)?

I've read about this one before, but haven't got a clue as to the why of
this!

Robert
--
Robert AH Prins
prin...@willis.com

Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.

Re:Unexpected slowdowns on AMD k6-2-400


Quote
> Also, on a (probably) unrelated note:  I am surprised that I did not get
> the famed RTE 200 bug.  All of the programs I wrote that use the CRT
> module still work.  Why would that be (not that I'm complaining or
> anything)?

I also don't know that. But if you use delay, the speed differences
can be explained with that. It seems that the delay doesn't work on
fast AMDs like it should. It returns in alot of cases only random
times as result. Maybe that's the exchange for the RTE 200.

Bye,
Stefan
--
please remove the P in my email-adress to answer me
take a look @ my homepage: http://sourcenet.home.pages.de/

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