From: Tom Barbette Date: Thu, 2 May 2019 12:11:33 +0000 (+0200) Subject: ethdev: add API to read device clock X-Git-Url: http://git.droids-corp.org/?a=commitdiff_plain;h=5e741377657c8fce28037e025ea2f12371400476;p=dpdk.git ethdev: add API to read device clock Add rte_eth_read_clock to read the raw clock of a device. The main use is to get the device clock conversion co-efficients to be able to translate the raw clock of the timestamp field of the pkt mbuf to a local synced time value. This function was missing to allow users to convert the Rx timestamp field to real time without the complexity of the rte_timesync* facility. One can derivate the clock frequency by calling twice read_clock and then keep a common time base. Signed-off-by: Tom Barbette Acked-by: Andrew Rybchenko --- diff --git a/doc/guides/nics/features.rst b/doc/guides/nics/features.rst index d57ddc2ff4..6f8cac2c81 100644 --- a/doc/guides/nics/features.rst +++ b/doc/guides/nics/features.rst @@ -602,6 +602,7 @@ Supports Timestamp. * **[provides] mbuf**: ``mbuf.ol_flags:PKT_RX_TIMESTAMP``. * **[provides] mbuf**: ``mbuf.timestamp``. * **[provides] rte_eth_dev_info**: ``rx_offload_capa,rx_queue_offload_capa: DEV_RX_OFFLOAD_TIMESTAMP``. +* **[related] eth_dev_ops**: ``read_clock``. .. _nic_features_macsec_offload: diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c index 72bb33881e..47546136a8 100644 --- a/lib/librte_ethdev/rte_ethdev.c +++ b/lib/librte_ethdev/rte_ethdev.c @@ -4171,6 +4171,18 @@ rte_eth_timesync_write_time(uint16_t port_id, const struct timespec *timestamp) timestamp)); } +int +rte_eth_read_clock(uint16_t port_id, uint64_t *clock) +{ + struct rte_eth_dev *dev; + + RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV); + dev = &rte_eth_devices[port_id]; + + RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->read_clock, -ENOTSUP); + return eth_err(port_id, (*dev->dev_ops->read_clock)(dev, clock)); +} + int rte_eth_dev_get_reg_info(uint16_t port_id, struct rte_dev_reg_info *info) { diff --git a/lib/librte_ethdev/rte_ethdev.h b/lib/librte_ethdev/rte_ethdev.h index bd20745dd0..5dd11afffd 100644 --- a/lib/librte_ethdev/rte_ethdev.h +++ b/lib/librte_ethdev/rte_ethdev.h @@ -3794,6 +3794,53 @@ int rte_eth_timesync_read_time(uint16_t port_id, struct timespec *time); */ int rte_eth_timesync_write_time(uint16_t port_id, const struct timespec *time); +/** + * @warning + * @b EXPERIMENTAL: this API may change without prior notice. + * + * Read the current clock counter of an Ethernet device + * + * This returns the current raw clock value of an Ethernet device. It is + * a raw amount of ticks, with no given time reference. + * The value returned here is from the same clock than the one + * filling timestamp field of Rx packets when using hardware timestamp + * offload. Therefore it can be used to compute a precise conversion of + * the device clock to the real time. + * + * E.g, a simple heuristic to derivate the frequency would be: + * uint64_t start, end; + * rte_eth_read_clock(port, start); + * rte_delay_ms(100); + * rte_eth_read_clock(port, end); + * double freq = (end - start) * 10; + * + * Compute a common reference with: + * uint64_t base_time_sec = current_time(); + * uint64_t base_clock; + * rte_eth_read_clock(port, base_clock); + * + * Then, convert the raw mbuf timestamp with: + * base_time_sec + (double)(mbuf->timestamp - base_clock) / freq; + * + * This simple example will not provide a very good accuracy. One must + * at least measure multiple times the frequency and do a regression. + * To avoid deviation from the system time, the common reference can + * be repeated from time to time. The integer division can also be + * converted by a multiplication and a shift for better performance. + * + * @param port_id + * The port identifier of the Ethernet device. + * @param clock + * Pointer to the uint64_t that holds the raw clock value. + * + * @return + * - 0: Success. + * - -ENODEV: The port ID is invalid. + * - -ENOTSUP: The function is not supported by the Ethernet driver. + */ +int __rte_experimental +rte_eth_read_clock(uint16_t port_id, uint64_t *clock); + /** * Config l2 tunnel ether type of an Ethernet device for filtering specific * tunnel packets by ether type. diff --git a/lib/librte_ethdev/rte_ethdev_core.h b/lib/librte_ethdev/rte_ethdev_core.h index b406e297e8..2922d5b7cc 100644 --- a/lib/librte_ethdev/rte_ethdev_core.h +++ b/lib/librte_ethdev/rte_ethdev_core.h @@ -322,6 +322,10 @@ typedef int (*eth_timesync_write_time)(struct rte_eth_dev *dev, const struct timespec *timestamp); /**< @internal Function used to get time from the device clock */ +typedef int (*eth_read_clock)(struct rte_eth_dev *dev, + uint64_t *timestamp); +/**< @internal Function used to get the current value of the device clock. */ + typedef int (*eth_get_reg_t)(struct rte_eth_dev *dev, struct rte_dev_reg_info *info); /**< @internal Retrieve registers */ @@ -496,6 +500,8 @@ struct eth_dev_ops { eth_timesync_read_time timesync_read_time; /** Get the device clock time. */ eth_timesync_write_time timesync_write_time; /** Set the device clock time. */ + eth_read_clock read_clock; + eth_xstats_get_by_id_t xstats_get_by_id; /**< Get extended device statistic values by ID. */ eth_xstats_get_names_by_id_t xstats_get_names_by_id; diff --git a/lib/librte_ethdev/rte_ethdev_version.map b/lib/librte_ethdev/rte_ethdev_version.map index afcd255991..df9141825c 100644 --- a/lib/librte_ethdev/rte_ethdev_version.map +++ b/lib/librte_ethdev/rte_ethdev_version.map @@ -253,6 +253,7 @@ EXPERIMENTAL { rte_eth_dev_rx_intr_ctl_q_get_fd; rte_eth_find_next_of; rte_eth_find_next_sibling; + rte_eth_read_clock; rte_eth_switch_domain_alloc; rte_eth_switch_domain_free; rte_flow_conv; diff --git a/lib/librte_mbuf/rte_mbuf.h b/lib/librte_mbuf/rte_mbuf.h index e4c2da6ee6..0d9fef0834 100644 --- a/lib/librte_mbuf/rte_mbuf.h +++ b/lib/librte_mbuf/rte_mbuf.h @@ -668,6 +668,8 @@ struct rte_mbuf { /** Valid if PKT_RX_TIMESTAMP is set. The unit and time reference * are not normalized but are always the same for a given port. + * Some devices allow to query rte_eth_read_clock that will return the + * current device timestamp. */ uint64_t timestamp;