[RFC,1/3] net/mlx5: add timestamp-to-ns converter from libibverbs
diff mbox series

Message ID 20200625190119.265739-2-vivien.didelot@gmail.com
State Deferred
Delegated to: Ferruh Yigit
Headers show
Series
  • mlx5 to PCAP capture with hardware timestamps
Related show

Checks

Context Check Description
ci/checkpatch success coding style OK

Commit Message

Vivien Didelot June 25, 2020, 7:01 p.m. UTC
From: Patrick Keroulas <patrick.keroulas@radio-canada.ca>

While some devices update their own clock info to provide current time,
mlx5dv part of libibverbs already handles this and also converts any
raw counter cycle to nanoseconds.

Signed-off-by: Patrick Keroulas <patrick.keroulas@radio-canada.ca>
---
 drivers/common/mlx5/linux/mlx5_glue.c   | 16 +++++++++++++
 drivers/common/mlx5/linux/mlx5_glue.h   |  4 ++++
 drivers/net/mlx5/linux/mlx5_ethdev_os.c | 30 +++++++++++++++++++++++++
 drivers/net/mlx5/linux/mlx5_os.c        |  1 +
 drivers/net/mlx5/mlx5.h                 |  1 +
 5 files changed, 52 insertions(+)

Comments

Patrick Keroulas July 7, 2020, 3:23 p.m. UTC | #1
On Fri, Jun 26, 2020 at 2:41 AM Olivier Matz <olivier.matz@6wind.com> wrote:
> Should mlx5dv_get_clock_info() be called for each convesion? In the man
> page [1], we can read this:
>
>        If the clock_info becomes too old then time conversion will return
>        wrong conversion results.  The user must ensure that
>        mlx5dv_get_clock_info(3) is called at least once every
>        max_clock_info_update_nsec as returned by the mlx5dv_query_device(3)
>        function.
>
> I understand this as mlx5dv_get_clock_info() being slower than
> mlx5dv_ts_to_ns(), and should not be called for each packet.

Right. I plan to use rte_timer (like in drivers/net/ena/) to query clock info
periodically.

>
> I suppose that when rdma-core library does a conversion to nanosec, it
> takes in account the fact that system and device are not synchronized
> (are they?).

PTP daemon like linuxptp is in charge of syncing both device and system
clocks with external master.

Thanks.
PK

Patch
diff mbox series

diff --git a/drivers/common/mlx5/linux/mlx5_glue.c b/drivers/common/mlx5/linux/mlx5_glue.c
index c91ee33bb..cac24015b 100644
--- a/drivers/common/mlx5/linux/mlx5_glue.c
+++ b/drivers/common/mlx5/linux/mlx5_glue.c
@@ -80,6 +80,20 @@  mlx5_glue_query_rt_values_ex(struct ibv_context *context,
 	return ibv_query_rt_values_ex(context, values);
 }
 
+static int
+mlx5_glue_get_clock_info(struct ibv_context *context,
+			  struct mlx5dv_clock_info *clock_info)
+{
+	return mlx5dv_get_clock_info(context, clock_info);
+}
+
+static uint64_t
+mlx5_glue_mlx5dv_ts_to_ns(struct mlx5dv_clock_info *clock_info,
+			  uint64_t device_timestamp)
+{
+	return mlx5dv_ts_to_ns(clock_info, device_timestamp);
+}
+
 static int
 mlx5_glue_query_port(struct ibv_context *context, uint8_t port_num,
 		     struct ibv_port_attr *port_attr)
@@ -1207,6 +1221,8 @@  const struct mlx5_glue *mlx5_glue = &(const struct mlx5_glue) {
 	.query_device = mlx5_glue_query_device,
 	.query_device_ex = mlx5_glue_query_device_ex,
 	.query_rt_values_ex = mlx5_glue_query_rt_values_ex,
+	.get_clock_info = mlx5_glue_get_clock_info,
+	.convert_ts_to_ns = mlx5_glue_mlx5dv_ts_to_ns,
 	.query_port = mlx5_glue_query_port,
 	.create_comp_channel = mlx5_glue_create_comp_channel,
 	.destroy_comp_channel = mlx5_glue_destroy_comp_channel,
diff --git a/drivers/common/mlx5/linux/mlx5_glue.h b/drivers/common/mlx5/linux/mlx5_glue.h
index 5d238a40a..8d05e7398 100644
--- a/drivers/common/mlx5/linux/mlx5_glue.h
+++ b/drivers/common/mlx5/linux/mlx5_glue.h
@@ -123,6 +123,10 @@  struct mlx5_glue {
 			  struct ibv_port_attr *port_attr);
 	struct ibv_comp_channel *(*create_comp_channel)
 		(struct ibv_context *context);
+	int (*get_clock_info)(struct ibv_context *context,
+			       struct mlx5dv_clock_info *clock_info);
+	uint64_t (*convert_ts_to_ns)(struct mlx5dv_clock_info *clock_info,
+			  uint64_t device_timestamp);
 	int (*destroy_comp_channel)(struct ibv_comp_channel *channel);
 	struct ibv_cq *(*create_cq)(struct ibv_context *context, int cqe,
 				    void *cq_context,
diff --git a/drivers/net/mlx5/linux/mlx5_ethdev_os.c b/drivers/net/mlx5/linux/mlx5_ethdev_os.c
index ab47cb531..86bec111b 100644
--- a/drivers/net/mlx5/linux/mlx5_ethdev_os.c
+++ b/drivers/net/mlx5/linux/mlx5_ethdev_os.c
@@ -355,6 +355,36 @@  mlx5_set_flags(struct rte_eth_dev *dev, unsigned int keep, unsigned int flags)
 	return mlx5_ifreq(dev, SIOCSIFFLAGS, &request);
 }
 
+/**
+ * Convert raw clock counter to nanoseconds
+ *
+ * @param dev
+ *   Pointer to Ethernet device structure.
+ * @param[in&out] timestamp
+ *   Pointer to the timestamp to be converted.
+ *
+ * @return
+ *   0 if the clock has correctly been read
+ *   The value of errno in case of error
+ */
+int
+mlx5_convert_ts_to_ns(struct rte_eth_dev *dev, uint64_t *timestamp)
+{
+	struct mlx5_priv *priv = dev->data->dev_private;
+	struct ibv_context *ctx = priv->sh->ctx;
+	struct mlx5dv_clock_info clock_info;
+
+	int err = mlx5_glue->get_clock_info(ctx, &clock_info);
+	if (err != 0) {
+		DRV_LOG(WARNING, "Could not get the clock info!");
+		return err;
+	}
+
+	*timestamp = mlx5_glue->convert_ts_to_ns(&clock_info, *timestamp);
+
+	return err;
+}
+
 /**
  * Get device current raw clock counter
  *
diff --git a/drivers/net/mlx5/linux/mlx5_os.c b/drivers/net/mlx5/linux/mlx5_os.c
index 3792371c3..914e58f52 100644
--- a/drivers/net/mlx5/linux/mlx5_os.c
+++ b/drivers/net/mlx5/linux/mlx5_os.c
@@ -2408,6 +2408,7 @@  const struct eth_dev_ops mlx5_os_dev_sec_ops = {
 	.xstats_get_names = mlx5_xstats_get_names,
 	.fw_version_get = mlx5_fw_version_get,
 	.dev_infos_get = mlx5_dev_infos_get,
+	.convert_ts_to_ns = mlx5_convert_ts_to_ns,
 	.rx_descriptor_status = mlx5_rx_descriptor_status,
 	.tx_descriptor_status = mlx5_tx_descriptor_status,
 	.rxq_info_get = mlx5_rxq_info_get,
diff --git a/drivers/net/mlx5/mlx5.h b/drivers/net/mlx5/mlx5.h
index 5bd5acd9d..dc469f7d9 100644
--- a/drivers/net/mlx5/mlx5.h
+++ b/drivers/net/mlx5/mlx5.h
@@ -738,6 +738,7 @@  int mlx5_get_mtu(struct rte_eth_dev *dev, uint16_t *mtu);
 int mlx5_set_flags(struct rte_eth_dev *dev, unsigned int keep,
 		   unsigned int flags);
 int mlx5_set_mtu(struct rte_eth_dev *dev, uint16_t mtu);
+int mlx5_convert_ts_to_ns(struct rte_eth_dev *dev, uint64_t *timestamp);
 int mlx5_read_clock(struct rte_eth_dev *dev, uint64_t *clock);
 int mlx5_link_update(struct rte_eth_dev *dev, int wait_to_complete);
 int mlx5_force_link_status_change(struct rte_eth_dev *dev, int status);