Hi,
if you want to have long periods, you should read the follwing discussion from 12/99
on the mailinglist:
Bernd
--- snip ---
Hi Pete,
thank you for pointing this out. I think you are right. I found
information on the counter (an PC-Motherboards) on the web confirming
what you've written.
On SMP boxes an other counter (APIC) isn used. (I think it uses 32bit
wide registers).
Bernd
Peter Cavender wrote:
>
> >Hi!
> >
> >Running the measurement example in periodic mode with periods larger
> >then 100ms I get strange results on a single cpu machine (i.e. the
> >period is much shorter) whereas on a smp machine it works fine. I am
> >using rtl-2.0 with linux kernel 2.2.13.
> >
> >This is not a real problem but if anybody knows something about that, it
> >would be interesting.
> >
> >Greetings
> > Bernd
>
> I may be mistaken, but doesn't the counter chip only have 16 bits..?,
> and at 1.1 Mhz it would wrap in about 60mS. If this is the case, I
> have no idea why it works on a SMP box.
>
> Pete
--- snap ----
On Fri, 18 February 2000, Kenneth Jacker wrote:
>
> kalatwal> For Linux on a 32-bit machine (Pentium): short = 8 bits
> kalatwal> int = 16 bits long = 32 bits = one word long long = 64
> kalatwal> bits = two words
>
> I've got to be the biggest idiot! I even wrote a one line program
> [ ... (printf("%d\n", sizeof(long long)); ...] to determine the number
> of bytes in a "long long". The printf produced an "8". Duh: 8x8=64!
>
> Apparently, I "thought" 8x8=32 ... or a byte contained 4 bits ... :-(
>
> Sorry to waste the bandwidth,
>
> -Kenneth
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