Re: PC timer

Dirk Bruere at Neopax wrote:
> On a modern PC what is the best resolution I can get from reading the clock?
> I need to timestamp data packets.
> Ideally I need sub millisecond res.

You can probably get that - tcpdump (well, windump) reports packet
times in microseconds. All the digits change but no idea what the
increment or accuracy actually is.

The old 8253 chip in the PC is clocked at 4.77 mhz / 4 or 1.193 MHz
giving a theoretical resolution of a bit less than a microsecond (or
perhaps half that rate, depending on the minimum count), if you either
reprogram the interrupt to happen that fast or figure out how to read
out the running count. Usually the interrupt was at the maximum 16 bit
divisor of that - 18.2 Hz, but many programs sped it up.

There may be other clocks in more modern designs?

.

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