Re: How much we can trust packet timestamping

uaca
2002-12-30T12:53:29Z

On Mon, Dec 30, 2002 at 01:09:03PM +0000, Alan Cox wrote:
> On Mon, 2002-12-30 at 11:28, uaca@alumni.uv.es wrote:
> > Hi all
> >
> > IMHO The problem is quite complicated because
> >
> > + common hardware is not designed for real time:
> >
> > - sends multiple PDUs within one interrupt, and can be delayed
> > - Host adapter bus & infraestructure is not designed to garantee latency
> > etc...
>
> The packet can be timestamped by the hardware receiving as well as by
> the kernel netif_rx code. This is actually intentional and there is
> hardware that supports doing IRQ raise time sampling which the driver
> can then use to get very accurate data.

Thanks Alan

Anybody know about a Linux driver that supports doing IRQ raise time
sampling? any doc/pointer/suggestion would be greatly appreciated

Thanks in advance

Ulisses
Debian GNU/Linux: a dream come true
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