Re: How much we can trust packet timestamping

Alan Cox
2002-12-30T12:19:06Z

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.

Alan