A full 64-bit NIC timestamp is periodically synced via an AdminQ command and cached in the driver. In the RX datapath, this cached value is used as a base to expand the 32-bit hardware timestamp into a full 64-bit value, which is then stored in the mbuf's dynamic timestamp field.
Signed-off-by: Mark Blasko <[email protected]> Reviewed-by: Joshua Washington <[email protected]> Reviewed-by: Jasper Tran O'Leary <[email protected]> --- v2: - Scoped timestamp offload capability advertisement strictly to DQO queues. - Predicated capability advertisement directly on memzone allocation. - Initialized mbuf_timestamp_offset to -1. - Added blank line separating release notes. --- doc/guides/nics/features/gve.ini | 1 + doc/guides/nics/gve.rst | 20 ++++++++++++++++++++ doc/guides/rel_notes/release_26_07.rst | 4 ++++ drivers/net/gve/base/gve_desc_dqo.h | 8 ++++++-- drivers/net/gve/gve_ethdev.c | 15 ++++++++++++++- drivers/net/gve/gve_ethdev.h | 25 +++++++++++++++++++++++++ drivers/net/gve/gve_rx_dqo.c | 26 ++++++++++++++++++++++++++ 7 files changed, 96 insertions(+), 3 deletions(-) diff --git a/doc/guides/nics/features/gve.ini b/doc/guides/nics/features/gve.ini index 89c97fd27a..117ad4fc65 100644 --- a/doc/guides/nics/features/gve.ini +++ b/doc/guides/nics/features/gve.ini @@ -13,6 +13,7 @@ RSS hash = Y RSS key update = Y RSS reta update = Y L4 checksum offload = Y +Timestamp offload = Y Basic stats = Y FreeBSD = Y Linux = Y diff --git a/doc/guides/nics/gve.rst b/doc/guides/nics/gve.rst index 62648c47ed..4c820ac5a6 100644 --- a/doc/guides/nics/gve.rst +++ b/doc/guides/nics/gve.rst @@ -72,6 +72,7 @@ Supported features of the GVE PMD are: - Tx UDP/TCP/SCTP Checksum - RSS hash configuration - RSS redirection table query and update +- Timestamp offload Currently, only GQI_QPL and GQI_RDA queue format are supported in PMD. Jumbo Frame is not supported in PMD for now. @@ -132,6 +133,25 @@ Security Protocols - Flow priorities are not supported (must be 0). - Masking is limited to full matches i.e. ``0x00...0`` or ``0xFF...F``. +Timestamp Offload +^^^^^^^^^^^^^^^^^ + +The driver supports hardware-based packet timestamping on supported +devices via the standard ``RTE_ETH_RX_OFFLOAD_TIMESTAMP`` offload capability. +While the ethdev ``.read_clock`` operation works regardless of queue format, +per-packet RX timestamp offloading requires the DQO queue format. + +**Limitations** + +- If the driver fails to fetch the NIC hardware clock for 7 consecutive periods, + the cached timestamp is marked as stale, + and the reconstructed timestamps are no longer propagated to the mbuf. +- The timestamp reconstruction is only accurate + if the time between a packet's reception + and the last hardware clock sync is less than approximately 2 seconds. + The driver's internal clock sync period is set to respect this limitation. + + Device Reset ^^^^^^^^^^^^ diff --git a/doc/guides/rel_notes/release_26_07.rst b/doc/guides/rel_notes/release_26_07.rst index 1b012c4776..f07152fe14 100644 --- a/doc/guides/rel_notes/release_26_07.rst +++ b/doc/guides/rel_notes/release_26_07.rst @@ -63,6 +63,10 @@ New Features ``rte_eal_init`` and the application is responsible for probing each device, * ``--auto-probing`` enables the initial bus probing, which is the current default behavior. +* **Updated Google GVE net driver.** + + * Added hardware timestamping support on DQO queues. + * **Updated PCAP ethernet driver.** * Added support for VLAN insertion and stripping. diff --git a/drivers/net/gve/base/gve_desc_dqo.h b/drivers/net/gve/base/gve_desc_dqo.h index 71d9d60bb9..c1534959c2 100644 --- a/drivers/net/gve/base/gve_desc_dqo.h +++ b/drivers/net/gve/base/gve_desc_dqo.h @@ -226,7 +226,8 @@ struct gve_rx_compl_desc_dqo { u8 status_error1; - __le16 reserved5; + u8 reserved5; + u8 ts_sub_nsecs_low; __le16 buf_id; /* Buffer ID which was sent on the buffer queue. */ union { @@ -237,9 +238,12 @@ struct gve_rx_compl_desc_dqo { }; __le32 hash; __le32 reserved6; - __le64 reserved7; + __le32 reserved7; + __le32 ts; /* timestamp in nanosecs */ } __packed; +#define GVE_DQO_RX_HWTSTAMP_VALID 0x1 + GVE_CHECK_STRUCT_LEN(32, gve_rx_compl_desc_dqo); /* Ringing the doorbell too often can hurt performance. diff --git a/drivers/net/gve/gve_ethdev.c b/drivers/net/gve/gve_ethdev.c index c600062faf..c0c715f804 100644 --- a/drivers/net/gve/gve_ethdev.c +++ b/drivers/net/gve/gve_ethdev.c @@ -214,6 +214,7 @@ static int gve_dev_configure(struct rte_eth_dev *dev) { struct gve_priv *priv = dev->data->dev_private; + int err; if (dev->data->dev_conf.rxmode.mq_mode & RTE_ETH_MQ_RX_RSS_FLAG) { dev->data->dev_conf.rxmode.offloads |= RTE_ETH_RX_OFFLOAD_RSS_HASH; @@ -223,13 +224,22 @@ gve_dev_configure(struct rte_eth_dev *dev) if (dev->data->dev_conf.rxmode.offloads & RTE_ETH_RX_OFFLOAD_TCP_LRO) priv->enable_rsc = 1; + if (dev->data->dev_conf.rxmode.offloads & RTE_ETH_RX_OFFLOAD_TIMESTAMP) { + err = rte_mbuf_dyn_rx_timestamp_register(&priv->mbuf_timestamp_offset, + &priv->mbuf_timestamp_mask); + if (err < 0) { + PMD_DRV_LOG(ERR, "Failed to register dynamic timestamp field"); + return err; + } + } + /* Reset RSS RETA in case number of queues changed. */ if (priv->rss_config.indir) { struct gve_rss_config update_reta_config; gve_init_rss_config_from_priv(priv, &update_reta_config); gve_generate_rss_reta(dev, &update_reta_config); - int err = gve_adminq_configure_rss(priv, &update_reta_config); + err = gve_adminq_configure_rss(priv, &update_reta_config); if (err) PMD_DRV_LOG(ERR, "Could not reconfigure RSS redirection table."); @@ -817,6 +827,8 @@ gve_dev_info_get(struct rte_eth_dev *dev, struct rte_eth_dev_info *dev_info) dev_info->min_mtu = RTE_ETHER_MIN_MTU; dev_info->rx_offload_capa = RTE_ETH_RX_OFFLOAD_RSS_HASH; + if (!gve_is_gqi(priv) && priv->nic_ts_report_mz) + dev_info->rx_offload_capa |= RTE_ETH_RX_OFFLOAD_TIMESTAMP; dev_info->tx_offload_capa = RTE_ETH_TX_OFFLOAD_MULTI_SEGS | RTE_ETH_TX_OFFLOAD_UDP_CKSUM | @@ -1652,6 +1664,7 @@ gve_dev_init(struct rte_eth_dev *eth_dev) priv->max_nb_txq = max_tx_queues; priv->max_nb_rxq = max_rx_queues; + priv->mbuf_timestamp_offset = -1; err = gve_init_priv(priv, false); if (err) return err; diff --git a/drivers/net/gve/gve_ethdev.h b/drivers/net/gve/gve_ethdev.h index 7e6f24e910..35d532284e 100644 --- a/drivers/net/gve/gve_ethdev.h +++ b/drivers/net/gve/gve_ethdev.h @@ -260,6 +260,7 @@ struct gve_rx_queue { struct rte_mbuf **refill_bufs; uint8_t is_gqi_qpl; + bool timestamp_enabled; }; struct gve_flow { @@ -368,8 +369,32 @@ struct gve_priv { RTE_ATOMIC(uint64_t) last_read_nic_timestamp; RTE_ATOMIC(uint32_t) nic_ts_read_fails; RTE_ATOMIC(uint8_t) nic_ts_stale; + + int mbuf_timestamp_offset; + uint64_t mbuf_timestamp_mask; }; +/* Expand the hardware timestamp to the full 64 bits of width. + * + * This algorithm works by using the passed hardware timestamp to generate a + * diff relative to the last read of the nic clock. This diff can be positive or + * negative, as it is possible that we have read the clock more recently than + * the hardware has received this packet. To detect this, we use the high bit of + * the diff, and assume that the read is more recent if the high bit is set. In + * this case we invert the process. + * + * Note that this means if the time delta between packet reception and the last + * clock read is greater than ~2 seconds, this will provide invalid results. + */ +static inline uint64_t +gve_reconstruct_ts(uint64_t last_sync, uint32_t ts) +{ + uint32_t low = (uint32_t)last_sync; + int32_t diff = (int32_t)(ts - low); + + return last_sync + diff; +} + static inline bool gve_is_gqi(struct gve_priv *priv) { diff --git a/drivers/net/gve/gve_rx_dqo.c b/drivers/net/gve/gve_rx_dqo.c index 8035aee572..cc343f3fd8 100644 --- a/drivers/net/gve/gve_rx_dqo.c +++ b/drivers/net/gve/gve_rx_dqo.c @@ -160,6 +160,8 @@ gve_rx_burst_dqo(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t nb_pkts) { volatile struct gve_rx_compl_desc_dqo *rx_desc; struct gve_rx_queue *rxq; + uint64_t last_sync = 0; + struct gve_priv *priv; struct rte_mbuf *rxm; uint16_t rx_buf_id; uint16_t pkt_len; @@ -171,6 +173,15 @@ gve_rx_burst_dqo(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t nb_pkts) nb_rx = 0; rxq = rx_queue; rx_id = rxq->rx_tail; + priv = rxq->hw; + + if (rxq->timestamp_enabled && + !rte_atomic_load_explicit(&priv->nic_ts_stale, + rte_memory_order_acquire)) { + last_sync = + rte_atomic_load_explicit(&priv->last_read_nic_timestamp, + rte_memory_order_relaxed); + } while (nb_rx < nb_pkts) { rx_desc = &rxq->compl_ring[rx_id]; @@ -208,6 +219,16 @@ gve_rx_burst_dqo(void *rx_queue, struct rte_mbuf **rx_pkts, uint16_t nb_pkts) gve_parse_csum_ol_flags(rxm, rx_desc); rxm->hash.rss = rte_le_to_cpu_32(rx_desc->hash); + if (last_sync != 0 && + (rx_desc->ts_sub_nsecs_low & GVE_DQO_RX_HWTSTAMP_VALID) && + priv->mbuf_timestamp_offset >= 0) { + uint32_t ts = rte_le_to_cpu_32(rx_desc->ts); + uint64_t full_ts = gve_reconstruct_ts(last_sync, ts); + + *RTE_MBUF_DYNFIELD(rxm, priv->mbuf_timestamp_offset, uint64_t *) = full_ts; + rxm->ol_flags |= priv->mbuf_timestamp_mask; + } + rx_pkts[nb_rx++] = rxm; bytes += pkt_len; } @@ -320,6 +341,11 @@ gve_rx_queue_setup_dqo(struct rte_eth_dev *dev, uint16_t queue_id, return -ENOMEM; } + /* Setup hardware timestamping if enabled */ + if ((conf->offloads & RTE_ETH_RX_OFFLOAD_TIMESTAMP) || + (dev->data->dev_conf.rxmode.offloads & RTE_ETH_RX_OFFLOAD_TIMESTAMP)) + rxq->timestamp_enabled = true; + /* check free_thresh here */ free_thresh = conf->rx_free_thresh ? conf->rx_free_thresh : GVE_DEFAULT_RX_FREE_THRESH; -- 2.54.0.563.g4f69b47b94-goog
