[PATCH 04/12] phylib: add a way to make PHY time stamps possible.
Grant Likely
grant.likely at secretlab.ca
Tue Jun 15 12:33:51 EDT 2010
On Tue, Jun 15, 2010 at 10:08 AM, Richard Cochran
<richardcochran at gmail.com> wrote:
> This patch adds a new networking option to allow hardware time stamps
> from PHY devices. Using PHY time stamps will still require adding two
> inline function calls to each MAC driver. The CONFIG option makes these
> calls safe to add, since the calls become NOOPs when the option is
> disabled.
>
> Signed-off-by: Richard Cochran <richard.cochran at omicron.at>
> ---
> include/linux/phy.h | 4 ++++
> include/linux/skbuff.h | 32 ++++++++++++++++++++++++++++++++
> net/Kconfig | 11 +++++++++++
> 3 files changed, 47 insertions(+), 0 deletions(-)
>
[...]
> diff --git a/net/Kconfig b/net/Kconfig
> index 0d68b40..3fa7ae3 100644
> --- a/net/Kconfig
> +++ b/net/Kconfig
> @@ -86,6 +86,17 @@ config NETWORK_SECMARK
> to nfmark, but designated for security purposes.
> If you are unsure how to answer this question, answer N.
>
> +config NETWORK_PHY_TIMESTAMPING
> + bool "Timestamping in PHY devices"
> + depends on EXPERIMENTAL
> + help
> + This allows timestamping of network packets by PHYs with
> + hardware timestamping capabilities. This option adds some
> + overhead in the transmit and receive paths. Note that this
> + option also requires support in the MAC driver.
Some overhead? At a brief glance of the series it looks like it could
add a lot of overhead, but I'm not fully clear on what the full
process is. Can you describe how the hardware timestamping works? I
could use an overview of what the kernel has to do.
g.
--
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.
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