Hi Aaron
From: Aaron Conole
> Sent: Monday, July 23, 2018 2:52 PM
> To: Matan Azrad <ma...@mellanox.com>
> Cc: dev@dpdk.org; Ferruh Yigit <ferruh.yi...@intel.com>; Marcelo Leitner
> <mleit...@redhat.com>; Shahaf Shuler <shah...@mellanox.com>; Ori Kam
> <or...@mellanox.com>; Thomas Monjalon <tho...@monjalon.net>
> Subject: Re: [dpdk-dev] [PATCH] ethdev: move sanity checks to non-debug paths
>
> Matan Azrad <ma...@mellanox.com> writes:
>
> > Hi Aaron
> >
> > From: Aaron Conole
> >> These checks would have prevented a reported crash in the field. If
> >> a user builds without ETHDEV_DEBUG, it should make their application
> >> more stable, not less.
> >>
> >> Many of these functions immediately dereference arrays based on the
> >> passed in values, so the sanity checks are quite important.
> >>
> >
> > These functions are datapath functions.
> > Do you really want to add more 3 checks + calculations per each burst call?
> > Did you check the performance impact?
> > I think that performance numbers must be added for the discussion of this
> patch.
>
> I'll dig up performance numbers - but performance doesn't mean anything if
> the application isn't running any longer due to crash.
Yes, I understand your point, but think about that, if we are going to defend
each user mistake it will cost a lot.
For example in Tx path, Adding checks for each mbuf pointer and mbuf data
validity will be very expensive.
I think the best way is to check the common user mistakes in DEBUG mode to help
for application debugging and that's it.
> >> The logs are left as DEBUG only.
> >>
> >> Cc: Marcelo Leitner <mleit...@redhat.com>
> >> Signed-off-by: Aaron Conole <acon...@redhat.com>
> >> ---
> >> lib/librte_ethdev/rte_ethdev.h | 29 +++++++++++++----------------
> >> 1 file changed, 13 insertions(+), 16 deletions(-)
> >>
> >> diff --git a/lib/librte_ethdev/rte_ethdev.h
> >> b/lib/librte_ethdev/rte_ethdev.h index f5f593b31..bfd6a3406 100644
> >> --- a/lib/librte_ethdev/rte_ethdev.h
> >> +++ b/lib/librte_ethdev/rte_ethdev.h
> >> @@ -3805,15 +3805,16 @@ rte_eth_rx_burst(uint16_t port_id, uint16_t
> >> queue_id,
> >> struct rte_eth_dev *dev = &rte_eth_devices[port_id];
> >> uint16_t nb_rx;
> >>
> >> -#ifdef RTE_LIBRTE_ETHDEV_DEBUG
> >> RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, 0);
> >> RTE_FUNC_PTR_OR_ERR_RET(*dev->rx_pkt_burst, 0);
> >>
> >> if (queue_id >= dev->data->nb_rx_queues) {
> >> +#ifdef RTE_LIBRTE_ETHDEV_DEBUG
> >> RTE_ETHDEV_LOG(ERR, "Invalid RX queue_id=%u\n",
> queue_id);
> >> +#endif
> >> return 0;
> >> }
> >> -#endif
> >> +
> >> nb_rx = (*dev->rx_pkt_burst)(dev->data->rx_queues[queue_id],
> >> rx_pkts, nb_pkts);
> >>
> >> @@ -3928,14 +3929,12 @@ rte_eth_rx_descriptor_status(uint16_t
> >> port_id, uint16_t queue_id,
> >> struct rte_eth_dev *dev;
> >> void *rxq;
> >>
> >> -#ifdef RTE_LIBRTE_ETHDEV_DEBUG
> >> RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV); -#endif
> >> dev = &rte_eth_devices[port_id];
> >> -#ifdef RTE_LIBRTE_ETHDEV_DEBUG
> >> +
> >> if (queue_id >= dev->data->nb_rx_queues)
> >> return -ENODEV;
> >> -#endif
> >> +
> >> RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->rx_descriptor_status, -
> >> ENOTSUP);
> >> rxq = dev->data->rx_queues[queue_id];
> >>
> >> @@ -3985,14 +3984,12 @@ static inline int
> >> rte_eth_tx_descriptor_status(uint16_t port_id,
> >> struct rte_eth_dev *dev;
> >> void *txq;
> >>
> >> -#ifdef RTE_LIBRTE_ETHDEV_DEBUG
> >> RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV); -#endif
> >> dev = &rte_eth_devices[port_id];
> >> -#ifdef RTE_LIBRTE_ETHDEV_DEBUG
> >> +
> >> if (queue_id >= dev->data->nb_tx_queues)
> >> return -ENODEV;
> >> -#endif
> >> +
> >> RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->tx_descriptor_status, -
> >> ENOTSUP);
> >> txq = dev->data->tx_queues[queue_id];
> >>
> >> @@ -4071,15 +4068,15 @@ rte_eth_tx_burst(uint16_t port_id, uint16_t
> >> queue_id, {
> >> struct rte_eth_dev *dev = &rte_eth_devices[port_id];
> >>
> >> -#ifdef RTE_LIBRTE_ETHDEV_DEBUG
> >> RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, 0);
> >> RTE_FUNC_PTR_OR_ERR_RET(*dev->tx_pkt_burst, 0);
> >>
> >> if (queue_id >= dev->data->nb_tx_queues) {
> >> +#ifdef RTE_LIBRTE_ETHDEV_DEBUG
> >> RTE_ETHDEV_LOG(ERR, "Invalid TX queue_id=%u\n",
> queue_id);
> >> +#endif
> >> return 0;
> >> }
> >> -#endif
> >>
> >> #ifdef RTE_ETHDEV_RXTX_CALLBACKS
> >> struct rte_eth_rxtx_callback *cb = dev->pre_tx_burst_cbs[queue_id];
> >> @@ -4160,23 +4157,23 @@ rte_eth_tx_prepare(uint16_t port_id, uint16_t
> >> queue_id, {
> >> struct rte_eth_dev *dev;
> >>
> >> -#ifdef RTE_LIBRTE_ETHDEV_DEBUG
> >> if (!rte_eth_dev_is_valid_port(port_id)) {
> >> +#ifdef RTE_LIBRTE_ETHDEV_DEBUG
> >> RTE_ETHDEV_LOG(ERR, "Invalid TX port_id=%u\n", port_id);
> >> +#endif
> >> rte_errno = -EINVAL;
> >> return 0;
> >> }
> >> -#endif
> >>
> >> dev = &rte_eth_devices[port_id];
> >>
> >> -#ifdef RTE_LIBRTE_ETHDEV_DEBUG
> >> if (queue_id >= dev->data->nb_tx_queues) {
> >> +#ifdef RTE_LIBRTE_ETHDEV_DEBUG
> >> RTE_ETHDEV_LOG(ERR, "Invalid TX queue_id=%u\n",
> queue_id);
> >> +#endif
> >> rte_errno = -EINVAL;
> >> return 0;
> >> }
> >> -#endif
> >>
> >> if (!dev->tx_pkt_prepare)
> >> return nb_pkts;
> >> --
> >> 2.14.3
