On Mon, Apr 20, 2015 at 08:51:26AM +0200, Marc Sune wrote:
>
>
> On 17/04/15 21:50, Wiles, Keith wrote:
> >Hi Marc and Bruce,
>
> Hi Keith, Bruce,
>
> >
> >On 4/17/15, 1:49 PM, "Marc Sune" <marc.sune at bisdn.de> wrote:
> What I was proposing is to try to add the minimum common shared state in
> order to properly demultiplex the RX/TX call and have a common set of
> abstract calls (the pkt_dev type). In a way, I was proposing to deliberately
> not have a shared struct rte_dev_data because I think the internals of the
> "pkt_dev" can be very different across devices (e.g. queues in kni vs eth
> port vs. crypto?). I treat the pkt_dev as a "black box" that conforms to
> TX/RX API, leaving the developer of that device to define its internal
> structures as it better suites the needs. I only use each of the specific
> device type TX/RX APIs (external to us, pkt_dev library) in rte_pkt_dev.h.
> This also simplifies the refactor required to eventually integrate the
> rte_pkt_dev library and builds it "on top" of the existing APIs.
>
> The other important difference with both, Bruce and your approach, and mine
> is the use of function pointers for RX/TX. I don't use them, which makes the
> entire abstracted TX/RX (including the final RX/TX routines itself)
> functions be "inlinable".
>
> Btw, I forgot to add something basic in the previous pseudo-code. The
> different types have to be conditionally compiled according to compiled-in
> DPDK libs:
>
> rte_pkt_dev.h:
>
> #include <rte_config.h>
>
> //Eth devices
> #ifdef RTE_LIBRTE_ETHER
> #include <rte_ethdev.h>
> #endif
>
> //KNI
> #ifdef RTE_LIBRTE_KNI
> #include <rte_kni.h>
> #endif
>
> //...
> //Include PMD (and non-PMD) TX/RX headers...
>
> static inline uint16_t
> rte_pkt_tx_burst(pkt_dev_t* dev, uint16_t queue_id,
> struct rte_mbuf **tx_pkts, uint16_t nb_pkts)
> {
> switch (((struct rte_pkt_dev_data*)dev)->type){
> #ifdef RTE_LIBRTE_ETHER
> case RTE_PKT_DEV_ETH:
> struct rte_eth_dev* eth_dev = (struct rte_eth_dev*)pkt_dev;
> rte_pkt_tx_burst(eth_dev, queue_id, tx_pkts, nb_pkts);
> break;
> #endif
>
> #ifdef RTE_LIBRTE_KNI
> case RTE_PKT_DEV_KNI:
> //...
> break;
> #endif
>
> default:
> //Corrupted type or unsupported (without compiled
> support)
> //Ignore or fail(fatal error)?
> break;
> }
> }
>
> //...
Yes, this is an interesting approach, and with the inlining could indeed be
less overhead for the ring and kni compared to my suggestion due to the
inlining.
There might be a slight overhead for the RX/TX ethdev functions though - 1/2
cycles due to the extra (hopefully predictable) branch in the RX/TX call, since
we always need the indirect function call for the PMDs.
I also like the use of pointers rather than port ids.
Let me think on this a bit more.
/Bruce
