From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 0D08442871; Thu, 30 Mar 2023 17:15:28 +0200 (CEST) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 9F19A410DC; Thu, 30 Mar 2023 17:15:27 +0200 (CEST) Received: from smartserver.smartsharesystems.com (smartserver.smartsharesystems.com [77.243.40.215]) by mails.dpdk.org (Postfix) with ESMTP id 3F52440E25 for ; Thu, 30 Mar 2023 17:15:26 +0200 (CEST) Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Subject: RE: [PATCH v5 1/3] ethdev: add API for buffer recycle mode Date: Thu, 30 Mar 2023 17:15:22 +0200 X-MimeOLE: Produced By Microsoft Exchange V6.5 Message-ID: <98CBD80474FA8B44BF855DF32C47DC35D8782B@smartserver.smartshare.dk> In-Reply-To: X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: [PATCH v5 1/3] ethdev: add API for buffer recycle mode Thread-Index: AQHZYtEPO3yD/9FA0E+nLV0H3CV5M68S6kqAgAAXoRCAAGCxwA== References: <20211224164613.32569-1-feifei.wang2@arm.com> <20230330062939.1206267-1-feifei.wang2@arm.com> <20230330062939.1206267-2-feifei.wang2@arm.com> <98CBD80474FA8B44BF855DF32C47DC35D8781F@smartserver.smartshare.dk> From: =?iso-8859-1?Q?Morten_Br=F8rup?= To: "Feifei Wang" , , "Ferruh Yigit" , "Andrew Rybchenko" Cc: , , "nd" , "Honnappa Nagarahalli" , "Ruifeng Wang" , "nd" X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org > From: Feifei Wang [mailto:Feifei.Wang2@arm.com] > Sent: Thursday, 30 March 2023 11.31 >=20 > > From: Morten Br=F8rup > > Sent: Thursday, March 30, 2023 3:19 PM > > > > > From: Feifei Wang [mailto:feifei.wang2@arm.com] > > > Sent: Thursday, 30 March 2023 08.30 > > > > > > > [...] > > > > > +/** > > > + * @internal > > > + * Rx routine for rte_eth_dev_buf_recycle(). > > > + * Refill Rx descriptors in buffer recycle mode. > > > + * > > > + * @note > > > + * This API can only be called by rte_eth_dev_buf_recycle(). > > > + * Before calling this API, rte_eth_tx_buf_stash() should be > > > + * called to stash Tx used buffers into Rx buffer ring. > > > + * > > > + * When this functionality is not implemented in the driver, the > > > +return > > > + * buffer number is 0. > > > + * > > > + * @param port_id > > > + * The port identifier of the Ethernet device. > > > + * @param queue_id > > > + * The index of the receive queue. > > > + * The value must be in the range [0, nb_rx_queue - 1] = previously > > supplied > > > + * to rte_eth_dev_configure(). > > > + *@param nb > > > + * The number of Rx descriptors to be refilled. > > > + * @return > > > + * The number Rx descriptors correct to be refilled. > > > + * - ENODEV: bad port or queue (only if compiled with debug). > > > > If you want errors reported by the return value, the function return = type > > cannot be uint16_t. > Agree. Actually, in the code path, if errors happen, the function will = return > 0. > For this description line, I refer to 'rte_eth_tx_prepare' notes. = Maybe we > should delete > this line. >=20 > > > > > + */ > > > +static inline uint16_t rte_eth_rx_descriptors_refill(uint16_t = port_id, > > > + uint16_t queue_id, uint16_t nb) > > > +{ > > > + struct rte_eth_fp_ops *p; > > > + void *qd; > > > + > > > +#ifdef RTE_ETHDEV_DEBUG_RX > > > + if (port_id >=3D RTE_MAX_ETHPORTS || > > > + queue_id >=3D RTE_MAX_QUEUES_PER_PORT) { > > > + RTE_ETHDEV_LOG(ERR, > > > + "Invalid port_id=3D%u or queue_id=3D%u\n", > > > + port_id, queue_id); > > > + rte_errno =3D ENODEV; > > > + return 0; > > > > If p->rx_descriptors_refill() is likely to return 0, this function = should > not use 0 > > as return value to indicate errors. > However, refer to dpdk code style in ethdev, most of API write like = this. > For example, 'rte_eth_rx/tx_burst', 'rte_eth_tx_prep'. >=20 > I'm also confused what's return type for this due to I want > to indicate errors and show the processed buffer number. OK. Thanks for the references. Looking at rte_eth_rx/tx_burst(), you could follow the same conventions = here, i.e.: - Use uint16_t as return type. - Return 0 on error. - Do not set rte_errno. - Remove the "ENODEV" line from the @return description. - Use RTE_ETHDEV_LOG(ERR,...) as the only method to indicate errors. I now see that you follow the convention of rte_eth_tx_prepare(). This = is also perfectly fine; then you just need to update the description of = @return to mention that the error value is set in rte_errno if a value = less than 'nb' is returned. >=20 > > > > > + } > > > +#endif > > > + > > > + p =3D &rte_eth_fp_ops[port_id]; > > > + qd =3D p->rxq.data[queue_id]; > > > + > > > +#ifdef RTE_ETHDEV_DEBUG_RX > > > + if (!rte_eth_dev_is_valid_port(port_id)) { > > > + RTE_ETHDEV_LOG(ERR, "Invalid Rx port_id=3D%u\n", port_id); > > > + rte_errno =3D ENODEV; > > > + return 0; > > > + > > > + if (qd =3D=3D NULL) { > > > + RTE_ETHDEV_LOG(ERR, "Invalid Rx queue_id=3D%u for > > port_id=3D%u\n", > > > + queue_id, port_id); > > > + rte_errno =3D ENODEV; > > > + return 0; > > > + } > > > +#endif > > > + > > > + if (p->rx_descriptors_refill =3D=3D NULL) > > > + return 0; > > > + > > > + return p->rx_descriptors_refill(qd, nb); } When does p->rx_descriptors_refill() return anything else than 'nb'? If p->rx_descriptors_refill() always succeeds (and thus always returns = 'nb'), you could make its return type void. And thus, you could also = make the return type of rte_eth_rx_descriptors_refill() void. > > > + > > > /**@{@name Rx hardware descriptor states > > > * @see rte_eth_rx_descriptor_status > > > */ > > > @@ -6483,6 +6597,122 @@ rte_eth_tx_buffer(uint16_t port_id, = uint16_t > > queue_id, > > > return rte_eth_tx_buffer_flush(port_id, queue_id, buffer); } > > > > > > +/** > > > + * @internal > > > + * Tx routine for rte_eth_dev_buf_recycle(). > > > + * Stash Tx used buffers into Rx buffer ring in buffer recycle = mode. > > > + * > > > + * @note > > > + * This API can only be called by rte_eth_dev_buf_recycle(). > > > + * After calling this API, rte_eth_rx_descriptors_refill() should = be > > > + * called to refill Rx ring descriptors. > > > + * > > > + * When this functionality is not implemented in the driver, the > > > +return > > > + * buffer number is 0. > > > + * > > > + * @param port_id > > > + * The port identifier of the Ethernet device. > > > + * @param queue_id > > > + * The index of the transmit queue. > > > + * The value must be in the range [0, nb_tx_queue - 1] = previously > > supplied > > > + * to rte_eth_dev_configure(). > > > + * @param rxq_buf_recycle_info > > > + * A pointer to a structure of Rx queue buffer ring information = in > buffer > > > + * recycle mode. > > > + * > > > + * @return > > > + * The number buffers correct to be filled in the Rx buffer = ring. > > > + * - ENODEV: bad port or queue (only if compiled with debug). > > > > If you want errors reported by the return value, the function return = type > > cannot be uint16_t. I now see that you follow the convention of rte_eth_tx_prepare() here = too. This is perfectly fine; then you just need to update the description of = @return to mention that the error value is set in rte_errno if a value = less than 'nb' is returned. > > > > > + */ > > > +static inline uint16_t rte_eth_tx_buf_stash(uint16_t port_id, > > > +uint16_t > > > queue_id, > > > + struct rte_eth_rxq_buf_recycle_info *rxq_buf_recycle_info) > > { > > > + struct rte_eth_fp_ops *p; > > > + void *qd; > > > + > > > +#ifdef RTE_ETHDEV_DEBUG_TX > > > + if (port_id >=3D RTE_MAX_ETHPORTS || > > > + queue_id >=3D RTE_MAX_QUEUES_PER_PORT) { > > > + RTE_ETHDEV_LOG(ERR, > > > + "Invalid port_id=3D%u or queue_id=3D%u\n", > > > + port_id, queue_id); > > > + rte_errno =3D ENODEV; > > > + return 0; > > > > If p->tx_buf_stash() is likely to return 0, this function should not = use 0 > as > > return value to indicate errors. I now see that you follow the convention of rte_eth_tx_prepare() here = too. Then please ignore my comment about using 0 as return value on = errors for this function. > > > > > + } > > > +#endif > > > + > > > + p =3D &rte_eth_fp_ops[port_id]; > > > + qd =3D p->txq.data[queue_id]; > > > + > > > +#ifdef RTE_ETHDEV_DEBUG_TX > > > + if (!rte_eth_dev_is_valid_port(port_id)) { > > > + RTE_ETHDEV_LOG(ERR, "Invalid Tx port_id=3D%u\n", port_id); > > > + rte_errno =3D ENODEV; > > > + return 0; > > > + > > > + if (qd =3D=3D NULL) { > > > + RTE_ETHDEV_LOG(ERR, "Invalid Tx queue_id=3D%u for > > port_id=3D%u\n", > > > + queue_id, port_id); > > > + rte_erno =3D ENODEV; > > > + return 0; > > > + } > > > +#endif > > > + > > > + if (p->tx_buf_stash =3D=3D NULL) > > > + return 0; > > > + > > > + return p->tx_buf_stash(qd, rxq_buf_recycle_info); } > > > + > > > +/** > > > + * @warning > > > + * @b EXPERIMENTAL: this API may change, or be removed, without = prior > > > +notice > > > + * > > > + * Buffer recycle mode can let Tx queue directly put used buffers > > > +into Rx > > > buffer > > > + * ring. This avoids freeing buffers into mempool and allocating > > > + buffers from > > > + * mempool. > > > > This function description generally describes the buffer recycle = mode. > > > > Please update it to describe what this specific function does. > Ack. > > > > > + * > > > + * @param rx_port_id > > > + * Port identifying the receive side. > > > + * @param rx_queue_id > > > + * The index of the receive queue identifying the receive side. > > > + * The value must be in the range [0, nb_rx_queue - 1] = previously > > supplied > > > + * to rte_eth_dev_configure(). > > > + * @param tx_port_id > > > + * Port identifying the transmit side. > > > + * @param tx_queue_id > > > + * The index of the transmit queue identifying the transmit = side. > > > + * The value must be in the range [0, nb_tx_queue - 1] = previously > > supplied > > > + * to rte_eth_dev_configure(). > > > + * @param rxq_recycle_info > > > + * A pointer to a structure of type *rte_eth_txq_rearm_data* to = be > filled. > > > + * @return > > > + * - (0) on success or no recycling buffer. > > > > Why not return the return value of rte_eth_rx_descriptors_refill() = instead > of > > 0 on success? (This is a question, not a suggestion.) > > > > Or, if rxq_buf_recycle_info must be valid, the function return type = could be > > void instead of int. > > > In some time, users may forget to allocate the room for ' = rxq_buf_recycle_info > ' > and call 'rte_rxq_buf_recycle_info_get' API. Thus, I think we need to = check > with this. If the user forgets to allocate the rxq_buf_recycle_info, it is a = serious bug in the user's application. We don't need to handle such bugs at runtime. >=20 > Furthermore, the return value of this API should return success or = not. If rxq_buf_recycle_info is not NULL, this function will always succeed. = So there is no need for a return value. If you want this function to return something, it could return nb_buf, = so the application can it use for telemetry purposes or similar. >=20 > > > + * - (-EINVAL) rxq_recycle_info is NULL. > > > + */ > > > +__rte_experimental > > > +static inline int > > > +rte_eth_dev_buf_recycle(uint16_t rx_port_id, uint16_t = rx_queue_id, > > > + uint16_t tx_port_id, uint16_t tx_queue_id, > > > + struct rte_eth_rxq_buf_recycle_info *rxq_buf_recycle_info) > > { > > > + /* The number of recycling buffers. */ > > > + uint16_t nb_buf; > > > + > > > + if (!rxq_buf_recycle_info) > > > + return -EINVAL; > > > > This is a fast path function. In which situation is this function = called > with > > rxq_buf_recycle_info =3D=3D NULL? > > > > If this function can genuinely be called with rxq_buf_recycle_info = =3D=3D NULL, > > you should test for (rxq_buf_recycle_info =3D=3D NULL), not (! > > rxq_buf_recycle_info). Otherwise, I think > > RTE_ASSERT(rxq_buf_recycle_info !=3D NULL) is more appropriate. > Agree. We should use ' RTE_ASSERT(rxq_buf_recycle_info !=3D NULL)'. > > > > > + > > > + /* Stash Tx used buffers into Rx buffer ring */ > > > + nb_buf =3D rte_eth_tx_buf_stash(tx_port_id, tx_queue_id, > > > + rxq_buf_recycle_info); > > > + /* If there are recycling buffers, refill Rx queue descriptors. = */ > > > + if (nb_buf) > > > + rte_eth_rx_descriptors_refill(rx_port_id, rx_queue_id, > > > + nb_buf); > > > + > > > + return 0; > > > +} > > > + > > > /** > > > * @warning > > > * @b EXPERIMENTAL: this API may change without prior notice diff > > > --git a/lib/ethdev/rte_ethdev_core.h = b/lib/ethdev/rte_ethdev_core.h > > > index dcf8adab92..a138fd4dbc 100644 > > > --- a/lib/ethdev/rte_ethdev_core.h > > > +++ b/lib/ethdev/rte_ethdev_core.h > > > @@ -56,6 +56,13 @@ typedef int (*eth_rx_descriptor_status_t)(void > > > *rxq, uint16_t offset); > > > /** @internal Check the status of a Tx descriptor */ typedef int > > > (*eth_tx_descriptor_status_t)(void *txq, uint16_t offset); > > > > > > +/** @internal Stash Tx used buffers into RX ring in buffer = recycle > > > +mode */ typedef uint16_t (*eth_tx_buf_stash_t)(void *txq, > > > + struct rte_eth_rxq_buf_recycle_info *rxq_buf_recycle_info); > > > + > > > +/** @internal Refill Rx descriptors in buffer recycle mode */ = typedef > > > +uint16_t (*eth_rx_descriptors_refill_t)(void *rxq, uint16_t nb); > > > > Please add proper function descriptions for the two callbacks above. > Ack. > > > > > + > > > /** > > > * @internal > > > * Structure used to hold opaque pointers to internal ethdev = Rx/Tx @@ > > > -90,9 +97,11 @@ struct rte_eth_fp_ops { > > > eth_rx_queue_count_t rx_queue_count; > > > /** Check the status of a Rx descriptor. */ > > > eth_rx_descriptor_status_t rx_descriptor_status; > > > + /** Refill Rx descriptors in buffer recycle mode */ > > > + eth_rx_descriptors_refill_t rx_descriptors_refill; > > > /** Rx queues data. */ > > > struct rte_ethdev_qdata rxq; > > > - uintptr_t reserved1[3]; > > > + uintptr_t reserved1[4]; > > > > You added a function pointer above, so to keep the structure = alignment, you > > must remove one here, not add one: > > > > - uintptr_t reserved1[3]; > > + uintptr_t reserved1[2]; > > > Ack. > > > /**@}*/ > > > > > > /**@{*/ > > > @@ -106,9 +115,11 @@ struct rte_eth_fp_ops { > > > eth_tx_prep_t tx_pkt_prepare; > > > /** Check the status of a Tx descriptor. */ > > > eth_tx_descriptor_status_t tx_descriptor_status; > > > + /** Stash Tx used buffers into RX ring in buffer recycle mode */ > > > + eth_tx_buf_stash_t tx_buf_stash; > > > /** Tx queues data. */ > > > struct rte_ethdev_qdata txq; > > > - uintptr_t reserved2[3]; > > > + uintptr_t reserved2[4]; > > > > You added a function pointer above, so to keep the structure = alignment, you > > must remove one here, not add one: > > > > - uintptr_t reserved1[3]; > > + uintptr_t reserved1[2]; > > > Ack. > > > /**@}*/ > > > > > > } __rte_cache_aligned;