Re: [PATCH for-next 09/10] IB/mlx4: Add timestamp_mask and hca_core_clock to query_device

Christoph Lameter
2015-05-28T17:14:15Z

On Thu, 28 May 2015, Jason Gunthorpe wrote:

> After a quick look through, the biggest question in my mind is what
> should the timestamp value in the wc be?
>
> Right now it is some coded thing in clock cycles.

This is sufficient since it can be converted to ns or whatever one wants.

> Should we require the driver to convert to ns before passing the wc
> back to the app? (Looks like the socket implementation uniformly uses
> us or ns)

But that requires additional processing.

> Should the app open code the conversion from clock cycles to ns, or
> vfunc down to the driver?

The API provides the abilty to retrieve the clock freq which is
sufficient for the user to convert the value to meaningful time values.