| Message ID | 20220112072324.30601-1-nmiki@yahoo-corp.jp (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Delegated to: | Ferruh Yigit |
| Headers | show |
| Series | [v2,1/1] net/tap: add a check that Rx/Tx have the same num of queues | expand |
| Context | Check | Description |
|---|---|---|
| ci/checkpatch | warning | coding style issues |
| ci/iol-broadcom-Functional | success | Functional Testing PASS |
| ci/iol-intel-Functional | success | Functional Testing PASS |
| ci/iol-mellanox-Performance | success | Performance Testing PASS |
| ci/github-robot: build | success | github build: passed |
| ci/iol-broadcom-Performance | success | Performance Testing PASS |
| ci/iol-intel-Performance | success | Performance Testing PASS |
| ci/iol-aarch64-unit-testing | success | Testing PASS |
| ci/iol-x86_64-compile-testing | success | Testing PASS |
| ci/iol-aarch64-compile-testing | success | Testing PASS |
| ci/iol-x86_64-unit-testing | success | Testing PASS |
| ci/iol-abi-testing | success | Testing PASS |
| ci/Intel-compilation | success | Compilation OK |
| ci/intel-Testing | success | Testing PASS |
On 1/12/2022 7:23 AM, Nobuhiro MIKI wrote: > Users can create the desired number of RxQ and TxQ in DPDK. For > example, if the number of RxQ = 2 and the number of TxQ = 5, > a total of 8 file descriptors will be created for a tap device, > including RxQ, TxQ, and one for keepalive. The RxQ and TxQ > with the same ID are paired by dup(2). > > In this scenario, Kernel will have 3 RxQ where packets are > incoming but not read. The reason for this is that there are only > 2 RxQ that are polled by DPDK, while there are 5 queues in Kernel. > This patch add a checking if DPDK has appropriate numbers of > queues to avoid unexpected packet drop. > > Signed-off-by: Nobuhiro MIKI <nmiki@yahoo-corp.jp> It makes sense to add this check, since the driver logic seem already has the assumption that Rx & Tx queue numbers will be same. But can you please update the tap documentation for this limitation/restriction? 'doc/guides/nics/tap.rst'. > --- > v2: fix commit message > > I had first discussed this issue in OVS [1], but changed my mind > that a fix in DPDK would be more appropriate. > [1]: https://mail.openvswitch.org/pipermail/ovs-dev/2021-November/389690.html > --- > drivers/net/tap/rte_eth_tap.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c > index 5bb472f1a6..02eb311e09 100644 > --- a/drivers/net/tap/rte_eth_tap.c > +++ b/drivers/net/tap/rte_eth_tap.c > @@ -940,6 +940,14 @@ tap_dev_configure(struct rte_eth_dev *dev) > RTE_PMD_TAP_MAX_QUEUES); > return -1; > } > + if (dev->data->nb_rx_queues != dev->data->nb_tx_queues) { > + TAP_LOG(ERR, > + "%s: number of rx queues %d must be equal to number of tx queues %d", > + dev->device->name, > + dev->data->nb_rx_queues, > + dev->data->nb_tx_queues); > + return -1; > + } > > TAP_LOG(INFO, "%s: %s: TX configured queues number: %u", > dev->device->name, pmd->name, dev->data->nb_tx_queues);
On Tue, Jan 18, 2022 at 12:31:51PM +0000, Ferruh Yigit wrote: > On 1/12/2022 7:23 AM, Nobuhiro MIKI wrote: > > Users can create the desired number of RxQ and TxQ in DPDK. For > > example, if the number of RxQ = 2 and the number of TxQ = 5, > > a total of 8 file descriptors will be created for a tap device, > > including RxQ, TxQ, and one for keepalive. The RxQ and TxQ > > with the same ID are paired by dup(2). > > > > In this scenario, Kernel will have 3 RxQ where packets are > > incoming but not read. The reason for this is that there are only > > 2 RxQ that are polled by DPDK, while there are 5 queues in Kernel. > > This patch add a checking if DPDK has appropriate numbers of > > queues to avoid unexpected packet drop. > > > > Signed-off-by: Nobuhiro MIKI <nmiki@yahoo-corp.jp> > > > It makes sense to add this check, since the driver logic seem already has > the assumption that Rx & Tx queue numbers will be same. > > But can you please update the tap documentation for this limitation/restriction? > 'doc/guides/nics/tap.rst'. Thanks for the review. I've updated doc/guides/nics/tap.rst and sent v3 patch.
diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c index 5bb472f1a6..02eb311e09 100644 --- a/drivers/net/tap/rte_eth_tap.c +++ b/drivers/net/tap/rte_eth_tap.c @@ -940,6 +940,14 @@ tap_dev_configure(struct rte_eth_dev *dev) RTE_PMD_TAP_MAX_QUEUES); return -1; } + if (dev->data->nb_rx_queues != dev->data->nb_tx_queues) { + TAP_LOG(ERR, + "%s: number of rx queues %d must be equal to number of tx queues %d", + dev->device->name, + dev->data->nb_rx_queues, + dev->data->nb_tx_queues); + return -1; + } TAP_LOG(INFO, "%s: %s: TX configured queues number: %u", dev->device->name, pmd->name, dev->data->nb_tx_queues);
Users can create the desired number of RxQ and TxQ in DPDK. For example, if the number of RxQ = 2 and the number of TxQ = 5, a total of 8 file descriptors will be created for a tap device, including RxQ, TxQ, and one for keepalive. The RxQ and TxQ with the same ID are paired by dup(2). In this scenario, Kernel will have 3 RxQ where packets are incoming but not read. The reason for this is that there are only 2 RxQ that are polled by DPDK, while there are 5 queues in Kernel. This patch add a checking if DPDK has appropriate numbers of queues to avoid unexpected packet drop. Signed-off-by: Nobuhiro MIKI <nmiki@yahoo-corp.jp> --- v2: fix commit message I had first discussed this issue in OVS [1], but changed my mind that a fix in DPDK would be more appropriate. [1]: https://mail.openvswitch.org/pipermail/ovs-dev/2021-November/389690.html --- drivers/net/tap/rte_eth_tap.c | 8 ++++++++ 1 file changed, 8 insertions(+)