Subject: Re: [linux-audio-dev] cycle counter wrapping
From: Roger Larsson (roger.larsson_AT_skelleftea.mail.telia.com)
Date: ti loka 12 1999 - 15:19:57 EDT
Paul Barton-Davis wrote:
>
> >What happens when the cycle_diff starts to wrap :-)
> >Ok, we have 2^64 bits, but wery soon we have 2^32 cycles/s CPUs.
> >1 GHz next year, and increasing rapidly (typing on a 180 MHz PPro
> >3 years old, assume 10 GHz in another 3 years, ...)
>
> even if we assume 10GHz, the cycle counter won't wrap for 58 years.
>
> 2^64 / 10^10 = 1844674407 seconds till wrap
> 1844674407 / (3600 * 24 * 365) = 58 years till wrap
>
> even Linux might not be up for that kind of uninterrupted uptime :)
>
> also, Moore's Law is supposed to bottom out in 3 to 5 years due to
> the fundamental physics of semiconductors.
>
Only future will tell...
But my point is that we should avoid code that can't handle
wraps correctly, it can be done without too much effort.
Like David's resyncronisation points (you do the resync when
no plugins run)
> --p
--The Internet interprets Windows as damage, and routes around it.
Roger Larsson Skellefteċ Sweden
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