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From: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
To: dev@dpdk.org
Cc: matan@mellanox.com, rasland@mellanox.com, olivier.matz@6wind.com,
	bernard.iremonger@intel.com, thomas@mellanox.net
Subject: [dpdk-dev] [PATCH v3 1/2] mbuf: introduce accurate packet Tx scheduling
Date: Tue,  7 Jul 2020 13:08:02 +0000
Message-ID: <1594127283-19863-1-git-send-email-viacheslavo@mellanox.com> (raw)
In-Reply-To: <1591771085-24959-1-git-send-email-viacheslavo@mellanox.com>

There is the requirement on some networks for precise traffic timing
management. The ability to send (and, generally speaking, receive)
the packets at the very precisely specified moment of time provides
the opportunity to support the connections with Time Division
Multiplexing using the contemporary general purpose NIC without involving
an auxiliary hardware. For example, the supporting of O-RAN Fronthaul
interface is one of the promising features for potentially usage of the
precise time management for the egress packets.

The main objective of this RFC is to specify the way how applications
can provide the moment of time at what the packet transmission must be
started and to describe in preliminary the supporting this feature from
mlx5 PMD side.

The new dynamic timestamp field is proposed, it provides some timing
information, the units and time references (initial phase) are not
explicitly defined but are maintained always the same for a given port.
Some devices allow to query rte_eth_read_clock() that will return
the current device timestamp. The dynamic timestamp flag tells whether
the field contains actual timestamp value. For the packets being sent
this value can be used by PMD to schedule packet sending.

After PKT_RX_TIMESTAMP flag and fixed timestamp field deprecation
and obsoleting, these dynamic flag and field will be used to manage
the timestamps on receiving datapath as well.

When PMD sees the "rte_dynfield_timestamp" set on the packet being sent
it tries to synchronize the time of packet appearing on the wire with
the specified packet timestamp. If the specified one is in the past it
should be ignored, if one is in the distant future it should be capped
with some reasonable value (in range of seconds). These specific cases
("too late" and "distant future") can be optionally reported via
device xstats to assist applications to detect the time-related
problems.

There is no any packet reordering according timestamps is supposed,
neither within packet burst, nor between packets, it is an entirely
application responsibility to generate packets and its timestamps
in desired order. The timestamps can be put only in the first packet
in the burst providing the entire burst scheduling.

PMD reports the ability to synchronize packet sending on timestamp
with new offload flag:

This is palliative and is going to be replaced with new eth_dev API
about reporting/managing the supported dynamic flags and its related
features. This API would break ABI compatibility and can't be introduced
at the moment, so is postponed to 20.11.

For testing purposes it is proposed to update testpmd "txonly"
forwarding mode routine. With this update testpmd application generates
the packets and sets the dynamic timestamps according to specified time
pattern if it sees the "rte_dynfield_timestamp" is registered.

The new testpmd command is proposed to configure sending pattern:

set tx_times <burst_gap>,<intra_gap>

<intra_gap> - the delay between the packets within the burst
              specified in the device clock units. The number
              of packets in the burst is defined by txburst parameter

<burst_gap> - the delay between the bursts in the device clock units

As the result the bursts of packet will be transmitted with specific
delays between the packets within the burst and specific delay between
the bursts. The rte_eth_get_clock is supposed to be engaged to get the
current device clock value and provide the reference for the timestamps.

Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
---
 lib/librte_ethdev/rte_ethdev.c |  1 +
 lib/librte_ethdev/rte_ethdev.h |  4 ++++
 lib/librte_mbuf/rte_mbuf_dyn.h | 32 ++++++++++++++++++++++++++++++++
 3 files changed, 37 insertions(+)

diff --git a/lib/librte_ethdev/rte_ethdev.c b/lib/librte_ethdev/rte_ethdev.c
index 8e10a6f..02157d5 100644
--- a/lib/librte_ethdev/rte_ethdev.c
+++ b/lib/librte_ethdev/rte_ethdev.c
@@ -162,6 +162,7 @@ struct rte_eth_xstats_name_off {
 	RTE_TX_OFFLOAD_BIT2STR(UDP_TNL_TSO),
 	RTE_TX_OFFLOAD_BIT2STR(IP_TNL_TSO),
 	RTE_TX_OFFLOAD_BIT2STR(OUTER_UDP_CKSUM),
+	RTE_TX_OFFLOAD_BIT2STR(SEND_ON_TIMESTAMP),
 };
 
 #undef RTE_TX_OFFLOAD_BIT2STR
diff --git a/lib/librte_ethdev/rte_ethdev.h b/lib/librte_ethdev/rte_ethdev.h
index a49242b..6f6454c 100644
--- a/lib/librte_ethdev/rte_ethdev.h
+++ b/lib/librte_ethdev/rte_ethdev.h
@@ -1178,6 +1178,10 @@ struct rte_eth_conf {
 /** Device supports outer UDP checksum */
 #define DEV_TX_OFFLOAD_OUTER_UDP_CKSUM  0x00100000
 
+/** Device supports send on timestamp */
+#define DEV_TX_OFFLOAD_SEND_ON_TIMESTAMP 0x00200000
+
+
 #define RTE_ETH_DEV_CAPA_RUNTIME_RX_QUEUE_SETUP 0x00000001
 /**< Device supports Rx queue setup after device started*/
 #define RTE_ETH_DEV_CAPA_RUNTIME_TX_QUEUE_SETUP 0x00000002
diff --git a/lib/librte_mbuf/rte_mbuf_dyn.h b/lib/librte_mbuf/rte_mbuf_dyn.h
index 96c3631..5b2f3da 100644
--- a/lib/librte_mbuf/rte_mbuf_dyn.h
+++ b/lib/librte_mbuf/rte_mbuf_dyn.h
@@ -250,4 +250,36 @@ int rte_mbuf_dynflag_lookup(const char *name,
 #define RTE_MBUF_DYNFIELD_METADATA_NAME "rte_flow_dynfield_metadata"
 #define RTE_MBUF_DYNFLAG_METADATA_NAME "rte_flow_dynflag_metadata"
 
+/**
+ * The timestamp dynamic field provides some timing information, the
+ * units and time references (initial phase) are not explicitly defined
+ * but are maintained always the same for a given port. Some devices allow
+ * to query rte_eth_read_clock() that will return the current device
+ * timestamp. The dynamic Tx timestamp flag tells whether the field contains
+ * actual timestamp value. For the packets being sent this value can be
+ * used by PMD to schedule packet sending.
+ *
+ * After PKT_RX_TIMESTAMP flag and fixed timestamp field deprecation
+ * and obsoleting, the dedicated Rx timestamp flag is supposed to be
+ * introduced and the shared timestamp field will be used to handle the
+ * timestamps on receiving datapath as well. Having the dedicated flags
+ * for Rx/Tx timstamps allows applications not to perform explicit flags
+ * reset on forwarding and not to promote received timestamps to the
+ * transmitting datapath by default.
+ *
+ * When PMD sees the RTE_MBUF_DYNFLAG_TX_TIMESTAMP_NAME flag set on the
+ * packet being sent it tries to synchronize the time of packet appearing
+ * on the wire with the specified packet timestamp. If the specified one
+ * is in the past it should be ignored, if one is in the distant future
+ * it should be capped with some reasonable value (in range of seconds).
+ *
+ * There is no any packet reordering according timestamps is supposed,
+ * neither within packet burst, nor between packets, it is an entirely
+ * application responsibility to generate packets and its timestamps in
+ * desired order. The timestamps might be put only in the first packet in
+ * the burst providing the entire burst scheduling.
+ */
+#define RTE_MBUF_DYNFIELD_TIMESTAMP_NAME "rte_dynfield_timestamp"
+#define RTE_MBUF_DYNFLAG_TX_TIMESTAMP_NAME "rte_dynflag_tx_timestamp"
+
 #endif
-- 
1.8.3.1


  parent reply	other threads:[~2020-07-07 13:08 UTC|newest]

Thread overview: 86+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-10  6:38 [dpdk-dev] [RFC] mbuf: " Viacheslav Ovsiienko
2020-06-10 13:33 ` Harman Kalra
2020-06-10 15:16   ` Slava Ovsiienko
2020-06-17 15:57     ` [dpdk-dev] [EXT] " Harman Kalra
2020-07-01 15:46       ` Slava Ovsiienko
2020-07-01 15:36 ` [dpdk-dev] [PATCH 1/2] mbuf: introduce " Viacheslav Ovsiienko
2020-07-01 15:36   ` [dpdk-dev] [PATCH 2/2] app/testpmd: add send scheduling test capability Viacheslav Ovsiienko
2020-07-07 11:50   ` [dpdk-dev] [PATCH 1/2] mbuf: introduce accurate packet Tx scheduling Olivier Matz
2020-07-07 12:46     ` Slava Ovsiienko
2020-07-07 12:59 ` [dpdk-dev] [PATCH v2 " Viacheslav Ovsiienko
2020-07-07 12:59   ` [dpdk-dev] [PATCH v2 2/2] app/testpmd: add send scheduling test capability Viacheslav Ovsiienko
2020-07-07 13:08 ` Viacheslav Ovsiienko [this message]
2020-07-07 13:08   ` [dpdk-dev] [PATCH v3 " Viacheslav Ovsiienko
2020-07-07 14:32   ` [dpdk-dev] [PATCH v3 1/2] mbuf: introduce accurate packet Tx scheduling Olivier Matz
2020-07-07 14:57 ` [dpdk-dev] [PATCH v4 " Viacheslav Ovsiienko
2020-07-07 14:57   ` [dpdk-dev] [PATCH v4 2/2] app/testpmd: add send scheduling test capability Viacheslav Ovsiienko
2020-07-07 15:23   ` [dpdk-dev] [PATCH v4 1/2] mbuf: introduce accurate packet Tx scheduling Olivier Matz
2020-07-08 14:16   ` [dpdk-dev] [PATCH v4 1/2] mbuf: introduce accurate packet Txscheduling Morten Brørup
2020-07-08 14:54     ` Slava Ovsiienko
2020-07-08 15:27       ` Morten Brørup
2020-07-08 15:51         ` Slava Ovsiienko
2020-07-08 15:47 ` [dpdk-dev] [PATCH v5 1/2] mbuf: introduce accurate packet Tx scheduling Viacheslav Ovsiienko
2020-07-08 15:47   ` [dpdk-dev] [PATCH v5 2/2] app/testpmd: add send scheduling test capability Viacheslav Ovsiienko
2020-07-08 16:05   ` [dpdk-dev] [PATCH v5 1/2] mbuf: introduce accurate packet Tx scheduling Slava Ovsiienko
2020-07-09 12:26   ` Thomas Monjalon
2020-07-09 12:36 ` [dpdk-dev] [PATCH v6 " Viacheslav Ovsiienko
2020-07-09 12:36   ` [dpdk-dev] [PATCH v6 2/2] app/testpmd: add send scheduling test capability Viacheslav Ovsiienko
2020-07-09 23:58     ` Ferruh Yigit
2020-07-10 12:41       ` Slava Ovsiienko
2020-07-09 23:47   ` [dpdk-dev] [PATCH v6 1/2] mbuf: introduce accurate packet Tx scheduling Ferruh Yigit
2020-07-10 12:32     ` Slava Ovsiienko
2020-07-10 12:39 ` [dpdk-dev] [PATCH v7 " Viacheslav Ovsiienko
2020-07-10 12:39   ` [dpdk-dev] [PATCH v7 2/2] app/testpmd: add send scheduling test capability Viacheslav Ovsiienko
2020-07-10 15:46   ` [dpdk-dev] [PATCH v7 1/2] mbuf: introduce accurate packet Tx scheduling Slava Ovsiienko
2020-07-10 22:07     ` Ferruh Yigit
2020-07-15  6:21 ` [dpdk-dev] [PATCH v2 00/17] net/mlx5: " Viacheslav Ovsiienko
2020-07-15  6:21   ` [dpdk-dev] [PATCH v2 01/17] common/mlx5: update common part to support packet pacing Viacheslav Ovsiienko
2020-07-15  6:21   ` [dpdk-dev] [PATCH v2 02/17] net/mlx5: introduce send scheduling devargs Viacheslav Ovsiienko
2020-07-15  6:21   ` [dpdk-dev] [PATCH v2 03/17] net/mlx5: fix UAR lock sharing for multiport devices Viacheslav Ovsiienko
2020-07-15  6:21   ` [dpdk-dev] [PATCH v2 04/17] net/mlx5: introduce shared UAR resource Viacheslav Ovsiienko
2020-07-15  6:21   ` [dpdk-dev] [PATCH v2 05/17] net/mlx5: create clock queue for packet pacing Viacheslav Ovsiienko
2020-07-15  6:21   ` [dpdk-dev] [PATCH v2 06/17] net/mlx5: create rearm " Viacheslav Ovsiienko
2020-07-15  6:21   ` [dpdk-dev] [PATCH v2 07/17] net/mlx5: create Tx queues with DevX Viacheslav Ovsiienko
2020-07-15  6:21   ` [dpdk-dev] [PATCH v2 08/17] net/mlx5: allocate packet pacing context Viacheslav Ovsiienko
2020-07-15  6:21   ` [dpdk-dev] [PATCH v2 09/17] net/mlx5: introduce clock queue service routine Viacheslav Ovsiienko
2020-07-15  6:21   ` [dpdk-dev] [PATCH v2 10/17] net/mlx5: prepare Tx queue structures to support timestamp Viacheslav Ovsiienko
2020-07-15  6:21   ` [dpdk-dev] [PATCH v2 11/17] net/mlx5: convert timestamp to completion index Viacheslav Ovsiienko
2020-07-15  6:21   ` [dpdk-dev] [PATCH v2 12/17] net/mlx5: prepare Tx datapath to support sheduling Viacheslav Ovsiienko
2020-07-15  6:21   ` [dpdk-dev] [PATCH v2 13/17] net/mlx5: add scheduling support to send routine template Viacheslav Ovsiienko
2020-07-15  6:21   ` [dpdk-dev] [PATCH v2 14/17] net/mlx5: add read device clock support Viacheslav Ovsiienko
2020-07-15  6:21   ` [dpdk-dev] [PATCH v2 15/17] net/mlx5: provide the send scheduling error statistics Viacheslav Ovsiienko
2020-07-15  6:21   ` [dpdk-dev] [PATCH v2 16/17] common/mlx5: add register access DevX routine Viacheslav Ovsiienko
2020-07-15  6:21   ` [dpdk-dev] [PATCH v2 17/17] net/mlx5: convert Rx timestamps in realtime format Viacheslav Ovsiienko
2020-07-16  8:23 ` [dpdk-dev] [PATCH v3 00/17] net/mlx5: introduce accurate packet Tx scheduling Viacheslav Ovsiienko
2020-07-16  8:23   ` [dpdk-dev] [PATCH v3 01/17] common/mlx5: update common part to support packet pacing Viacheslav Ovsiienko
2020-07-16  8:23   ` [dpdk-dev] [PATCH v3 02/17] net/mlx5: introduce send scheduling devargs Viacheslav Ovsiienko
2020-07-16  8:23   ` [dpdk-dev] [PATCH v3 03/17] net/mlx5: fix UAR lock sharing for multiport devices Viacheslav Ovsiienko
2020-07-16  8:23   ` [dpdk-dev] [PATCH v3 04/17] net/mlx5: introduce shared UAR resource Viacheslav Ovsiienko
2020-07-16  8:23   ` [dpdk-dev] [PATCH v3 05/17] net/mlx5: create clock queue for packet pacing Viacheslav Ovsiienko
2020-07-16  8:23   ` [dpdk-dev] [PATCH v3 06/17] net/mlx5: create rearm " Viacheslav Ovsiienko
2020-07-16  8:23   ` [dpdk-dev] [PATCH v3 07/17] net/mlx5: create Tx queues with DevX Viacheslav Ovsiienko
2020-07-20 14:18     ` Ferruh Yigit
2020-07-20 15:25       ` Ferruh Yigit
2020-07-21 11:35         ` Slava Ovsiienko
2020-07-16  8:23   ` [dpdk-dev] [PATCH v3 08/17] net/mlx5: allocate packet pacing context Viacheslav Ovsiienko
2020-07-16  8:23   ` [dpdk-dev] [PATCH v3 09/17] net/mlx5: introduce clock queue service routine Viacheslav Ovsiienko
2020-07-16  8:23   ` [dpdk-dev] [PATCH v3 10/17] net/mlx5: prepare Tx queue structures to support timestamp Viacheslav Ovsiienko
2020-07-16  8:23   ` [dpdk-dev] [PATCH v3 11/17] net/mlx5: convert timestamp to completion index Viacheslav Ovsiienko
2020-07-16  8:23   ` [dpdk-dev] [PATCH v3 12/17] net/mlx5: prepare Tx datapath to support sheduling Viacheslav Ovsiienko
2020-07-16  8:23   ` [dpdk-dev] [PATCH v3 13/17] net/mlx5: add scheduling support to send routine template Viacheslav Ovsiienko
2020-07-16  8:23   ` [dpdk-dev] [PATCH v3 14/17] net/mlx5: add read device clock support Viacheslav Ovsiienko
2020-07-16  8:23   ` [dpdk-dev] [PATCH v3 15/17] net/mlx5: provide the send scheduling error statistics Viacheslav Ovsiienko
2020-07-16  8:23   ` [dpdk-dev] [PATCH v3 16/17] common/mlx5: add register access DevX routine Viacheslav Ovsiienko
2020-07-16  8:23   ` [dpdk-dev] [PATCH v3 17/17] net/mlx5: convert Rx timestamps in realtime format Viacheslav Ovsiienko
2020-07-16 20:20   ` [dpdk-dev] [PATCH v3 00/17] net/mlx5: introduce accurate packet Tx scheduling Raslan Darawsheh
2020-07-17 14:28 ` [dpdk-dev] [PATCH 1/3] net/mlx5: fix compilation issue with missing DevX event Viacheslav Ovsiienko
2020-07-17 14:28   ` [dpdk-dev] [PATCH 2/3] net/mlx5: fix compilation issue with atomic128 exchange Viacheslav Ovsiienko
2020-07-17 15:08     ` Thomas Monjalon
2020-07-17 15:15       ` Slava Ovsiienko
2020-07-17 14:28   ` [dpdk-dev] [PATCH 3/3] common/mlx5: fix DevX register access opcode Viacheslav Ovsiienko
2020-07-17 15:05     ` Thomas Monjalon
2020-07-17 15:11       ` Slava Ovsiienko
2020-07-17 15:19         ` Thomas Monjalon
2020-07-17 15:23           ` Slava Ovsiienko
2020-07-17 15:59             ` Thomas Monjalon
2020-07-18 13:38   ` [dpdk-dev] [PATCH 1/3] net/mlx5: fix compilation issue with missing DevX event Raslan Darawsheh

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