> -----Original Message----- > From: Michal Miroslaw [mailto:mirq-li...@rere.qmqm.pl] > Sent: Tuesday, December 13, 2016 2:58 PM > To: Ananyev, Konstantin <konstantin.anan...@intel.com> > Cc: dev@dpdk.org > Subject: Re: [dpdk-dev] [PATCH 06/13] null: fake PMD capabilities > > On Tue, Dec 13, 2016 at 02:37:34PM +0000, Ananyev, Konstantin wrote: > > > > > > > -----Original Message----- > > > From: Michal Miroslaw [mailto:mirq-li...@rere.qmqm.pl] > > > Sent: Tuesday, December 13, 2016 2:27 PM > > > To: Ananyev, Konstantin <konstantin.anan...@intel.com> > > > Cc: dev@dpdk.org > > > Subject: Re: [dpdk-dev] [PATCH 06/13] null: fake PMD capabilities > > > > > > On Tue, Dec 13, 2016 at 10:48:32AM +0000, Ananyev, Konstantin wrote: > > > > > -----Original Message----- > > > > > From: dev [mailto:dev-boun...@dpdk.org] On Behalf Of Michal Miroslaw > > > > > Sent: Tuesday, December 13, 2016 1:08 AM > > > > > To: dev@dpdk.org > > > > > Subject: [dpdk-dev] [PATCH 06/13] null: fake PMD capabilities > > > > > > > > > > From: Paweł Małachowski <pawel.malachow...@atendesoftware.pl> > > > > > > > > > > Thanks to that change we can use Null PMD for testing purposes. > > > > > > > > > > Signed-off-by: Michał Mirosław <michal.miros...@atendesoftware.pl> > > > > > --- > > > > > drivers/net/null/rte_eth_null.c | 13 ++++++++++++- > > > > > 1 file changed, 12 insertions(+), 1 deletion(-) > > > > > > > > > > diff --git a/drivers/net/null/rte_eth_null.c > > > > > b/drivers/net/null/rte_eth_null.c > > > > > index 836d982..f32ba2a 100644 > > > > > --- a/drivers/net/null/rte_eth_null.c > > > > > +++ b/drivers/net/null/rte_eth_null.c > > > > > @@ -284,6 +284,9 @@ eth_tx_queue_setup(struct rte_eth_dev *dev, > > > > > uint16_t tx_queue_id, > > > > > return 0; > > > > > } > > > > > > > > > > +static void > > > > > +eth_dev_void_ok(struct rte_eth_dev *dev __rte_unused) { return; } > > > > > + > > > > > > > > > > static void > > > > > eth_dev_info(struct rte_eth_dev *dev, > > > > > @@ -304,6 +307,9 @@ eth_dev_info(struct rte_eth_dev *dev, > > > > > dev_info->pci_dev = NULL; > > > > > dev_info->reta_size = internals->reta_size; > > > > > dev_info->flow_type_rss_offloads = > > > > > internals->flow_type_rss_offloads; > > > > > + /* We hereby declare we can RX-offload VLAN-s out of thin air > > > > > and update checksums and VLANs before sinking > packets in > > > > > /dev/null */ > > > > > + dev_info->rx_offload_capa = DEV_RX_OFFLOAD_VLAN_STRIP; > > > > > + dev_info->tx_offload_capa = DEV_TX_OFFLOAD_VLAN_INSERT | > > > > > DEV_TX_OFFLOAD_IPV4_CKSUM; > > > > > > > > Hmm, how could it be supported if all that null PMD does on TX - just > > > > free the packets? > > > > Same question for RX. > > > > > > You could imagine, that before dropping the packet you insert the tag > > > and calculate the checksum. The observed effect will be the same. > > > > > > On RX this always indicates lack of VLAN tag. So whether the offload > > > is enabled or not it doesn't matter. > > > > Of course user can imagine whatever he likes, but what the point to > > advertise these capabilities, > > when the PMD clearly doesn't have them? > > Again, why these particular ones? > > Hmm. I guess we can expand the set. Those were the ones we actually use > (depend on) for testing our code. > > This allows to use null PMD for testing in place of real network interface > with those offloads.
As I can see on TX null pmd would just drop the packets, right? So the only thing you might check, as I understand, did upper layer code setup ol_flags and other mbuf fields properly depending on advertised capabilities (probably via sme special tx_callback installed or so). Is that correct? That's ok, I suppose, but if tomorrow you (or someone else) would like to test with different RX/TX offloads? Shouldn't be advertised offload capabilities be configurable at device creation/attach time somehow? Or at least just advertise all possible ones then? Konstantin >This patch is to keep users from having to place if's > around their code just to support test scenarios with null PMD. > > Best Regards, > Michał Mirosław
