On Fri, Jul 14, 2017 at 6:05 AM, Peltonen, Janne (Nokia - FI/Espoo) <
janne.pelto...@nokia.com> wrote:
> Hi,
>
> ODP API should somewhere define what exactly MTU means in the context of
> ODP.
>
> One can guess that transmission and reception of L2 frames larger than the
> configured MTU is not guaranteed to succeed, but which bytes are taken into
> account? For instance, is Ethernet FCS counted towards the MTU?
>
>
We've had this discussion before. The whole concept of MTU is a bit of an
anachronism from the early days of Ethernet. At speeds ODP is designed for
(10Gb and above) all equipment should be running with jumbo frames (MTU =
9K). All equipment capable of running at these speeds is capable of this
size, and 9K is the recommended default MTU for this equipment. So there's
really nothing one should need to control or change here.
It would be interesting to understand the use case that is driving the
desire to be able to set MTU.
The other consideration is that setting MTU (or MAC address) is a control
plane function, not a data plane function. Just as the control plane tells
the data plane which interfaces to use, the control plane is responsible
for this type of configuration, as well as managing and responding to
configuration changes. So again, it would be good to understand the use
case behind wanting to change these values in the data plane.
Janne
>
>
> > -----Original Message-----
> > From: lng-odp [mailto:lng-odp-boun...@lists.linaro.org] On Behalf Of
> Vamsi Attunuru
> > Sent: Friday, July 14, 2017 1:05 PM
> > To: lng-odp@lists.linaro.org
> > Cc: mcha...@cavium.com; pathr...@cavium.com; vattun...@cavium.com;
> sve...@cavium.com
> > Subject: [lng-odp] [API-NEXT PATCH v1 1/1] pktio APIs to set the MAC
> address and MTU size.
> >
> > Adds new pktio APIs to set MTU and MAC address on pktio interface.
> >
> > Signed-off-by: Vamsi Attunuru <vattun...@cavium.com>
> > Signed-off-by: Mahipal Challa <mcha...@cavium.com>
> > Signed-off-by: Shally Verma <sve...@cavium.com>
> >
> > ---
> > include/odp/api/spec/packet_io.h | 45 ++++++++++++++++++++++++++++++
> ++++++++++
> > 1 file changed, 45 insertions(+)
> >
> > diff --git a/include/odp/api/spec/packet_io.h
> b/include/odp/api/spec/packet_io.h
> > index 8802089..1269f44 100644
> > --- a/include/odp/api/spec/packet_io.h
> > +++ b/include/odp/api/spec/packet_io.h
> > @@ -451,6 +451,10 @@ typedef union odp_pktio_set_op_t {
> > struct {
> > /** Promiscuous mode */
> > uint32_t promisc_mode : 1;
> > + /** MAC address */
> > + uint32_t mac : 1;
> > + /** MTU size */
> > + uint32_t mtu : 1;
> > } op;
> > /** All bits of the bit field structure.
> > * This field can be used to set/clear all flags, or bitwise
> > @@ -482,6 +486,12 @@ typedef struct odp_pktio_capability_t {
> > * A boolean to denote whether loop back mode is supported on this
> > * specific interface. */
> > odp_bool_t loop_supported;
> > +
> > + /** Maximum MTU size supported */
> > + uint32_t max_mtu_size;
> > +
> > + /** Length of MAC address supported on this specific interface */
> > + uint32_t mac_addr_len;
> > } odp_pktio_capability_t;
> >
> > /**
> > @@ -912,6 +922,21 @@ int odp_pktout_send(odp_pktout_queue_t queue,
> const odp_packet_t
> > packets[],
> > uint32_t odp_pktio_mtu(odp_pktio_t pktio);
> >
> > /**
> > + * Set MTU value of a packet IO interface.
> > + *
> > + * Application should pass value upto max_mtu_size as indicated by
> > + * odp_pktio_capability_t:max_mtu_size. Any value beyond max_mtu_size
> > + * limit will result in failure.
> > + *
> > + * @param pktio Packet IO handle.
> > + * @param mtu MTU value to be set.
> > + *
> > + * @return 0 on success
> > + * @retval <0 on failure
> > + */
> > +int odp_pktio_mtu_set(odp_pktio_t pktio, uint32_t mtu);
> > +
> > +/**
> > * Enable/Disable promiscuous mode on a packet IO interface.
> > *
> > * @param[in] pktio Packet IO handle.
> > @@ -946,6 +971,26 @@ int odp_pktio_promisc_mode(odp_pktio_t pktio);
> > int odp_pktio_mac_addr(odp_pktio_t pktio, void *mac_addr, int size);
> >
> > /**
> > + * Set the MAC address of a packet IO interface.
> > + *
> > + * Application should pass mac_addr buffer with size >=
> > + * odp_pktio_capablity_t:mac_addr_len, size value less than
> > + * implementation supported will result in API failure.
> > + *
> > + * On success, Implementation would read mac_addr buffer bytes
> > + * upto mac_addr_len value indicated in capability information.
> > + *
> > + * @param pktio Packet IO handle
> > + * @param mac_addr Pointer to MAC address to be set
> > + * @param size Size of MAC address buffer
> > + *
> > + * @return 0 on success
> > + * @retval <0 on failure
> > + */
> > +int odp_pktio_mac_addr_set(odp_pktio_t pktio, const uint8_t *mac_addr,
> > + int size);
> > +
> > +/**
> > * Setup per-port default class-of-service.
> > *
> > * @param[in] pktio Ingress port pktio handle.
> > --
> > 1.9.3
>
>
