[xdp-hints] [PATCH bpf-next 0/3] xsk: TX metadata launch time support

[xdp-hints] [PATCH bpf-next 0/3] xsk: TX metadata launch time support

[Song Yoong Siang]

This series expands XDP TX metadata framework to include HW launch time offload.

Song Yoong Siang (3):
  xsk: add launch time support to XDP Tx metadata
  net: stmmac: Add launch time support to XDP ZC
  selftests/bpf: Add launch time to xdp_hw_metadata

 Documentation/netlink/specs/netdev.yaml        |  4 ++++
 Documentation/networking/xsk-tx-metadata.rst   |  5 +++++
 drivers/net/ethernet/stmicro/stmmac/stmmac.h   |  2 ++
 .../net/ethernet/stmicro/stmmac/stmmac_main.c  | 13 +++++++++++++
 include/net/xdp_sock.h                         | 10 ++++++++++
 include/net/xdp_sock_drv.h                     |  1 +
 include/uapi/linux/if_xdp.h                    |  9 +++++++++
 include/uapi/linux/netdev.h                    |  3 +++
 net/core/netdev-genl.c                         |  2 ++
 net/xdp/xsk.c                                  |  3 +++
 tools/include/uapi/linux/if_xdp.h              |  9 +++++++++
 tools/include/uapi/linux/netdev.h              |  3 +++
 tools/net/ynl/generated/netdev-user.c          |  1 +
 tools/testing/selftests/bpf/xdp_hw_metadata.c  | 18 +++++++++++++++++-
 14 files changed, 82 insertions(+), 1 deletion(-)

-- 
2.34.1

[xdp-hints] [PATCH bpf-next 1/3] xsk: add launch time support to XDP Tx metadata

[Song Yoong Siang]

This patch extends the XDP Tx metadata framework to include Time-Based
Scheduling (TBS) support where the NIC will schedule a packet for
transmission at a pre-determined time called launch time. The value of
launch time is communicated from user space to Ethernet driver via
launch_time field of struct xsk_tx_metadata.

Suggested-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Song Yoong Siang <yoong.siang.song@intel.com>
---
 Documentation/netlink/specs/netdev.yaml      |  4 ++++
 Documentation/networking/xsk-tx-metadata.rst |  5 +++++
 include/net/xdp_sock.h                       | 10 ++++++++++
 include/net/xdp_sock_drv.h                   |  1 +
 include/uapi/linux/if_xdp.h                  |  9 +++++++++
 include/uapi/linux/netdev.h                  |  3 +++
 net/core/netdev-genl.c                       |  2 ++
 net/xdp/xsk.c                                |  3 +++
 tools/include/uapi/linux/if_xdp.h            |  9 +++++++++
 tools/include/uapi/linux/netdev.h            |  3 +++
 tools/net/ynl/generated/netdev-user.c        |  1 +
 11 files changed, 50 insertions(+)

diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml
index 00439bcbd2e3..a602776bbfb4 100644
--- a/Documentation/netlink/specs/netdev.yaml
+++ b/Documentation/netlink/specs/netdev.yaml
@@ -66,6 +66,10 @@ definitions:
         name: tx-checksum
         doc:
           L3 checksum HW offload is supported by the driver.
+      -
+        name: launch-time
+        doc:
+          HW Time-Based Scheduling (TBS) is supported by the driver.
 
 attribute-sets:
   -
diff --git a/Documentation/networking/xsk-tx-metadata.rst b/Documentation/networking/xsk-tx-metadata.rst
index 97ecfa480d00..e3a7486f47e2 100644
--- a/Documentation/networking/xsk-tx-metadata.rst
+++ b/Documentation/networking/xsk-tx-metadata.rst
@@ -44,6 +44,10 @@ The flags field enables the particular offload:
   checksum. ``csum_start`` specifies byte offset of where the checksumming
   should start and ``csum_offset`` specifies byte offset where the
   device should store the computed checksum.
+- ``XDP_TXMD_FLAGS_LAUNCH_TIME``: requests HW Time-Based Scheduling (TBS)
+  offload to launch the packet at a pre-determined time. ``launch_time``
+  indicates the time which the NIC should schedule the packet for
+  transmission.
 
 Besides the flags above, in order to trigger the offloads, the first
 packet's ``struct xdp_desc`` descriptor should set ``XDP_TX_METADATA``
@@ -68,6 +72,7 @@ Refer to ``xsk-flags`` features bitmask in
 
 - ``tx-timestamp``: device supports ``XDP_TXMD_FLAGS_TIMESTAMP``
 - ``tx-checksum``: device supports ``XDP_TXMD_FLAGS_CHECKSUM``
+- ``launch-time``: device supports ``XDP_TXMD_FLAGS_LAUNCH_TIME``
 
 See ``tools/net/ynl/samples/netdev.c`` on how to query this information.
 
diff --git a/include/net/xdp_sock.h b/include/net/xdp_sock.h
index 3cb4dc9bd70e..f3e274830816 100644
--- a/include/net/xdp_sock.h
+++ b/include/net/xdp_sock.h
@@ -110,11 +110,16 @@ struct xdp_sock {
  *     indicates position where checksumming should start.
  *     csum_offset indicates position where checksum should be stored.
  *
+ * void (*tmo_request_launch_time)(u64 launch_time, void *priv)
+ *     Called when AF_XDP frame requested HW Time-Based Scheduling (TBS) offload
+ *     support. launch_time indicates the time which the NIC should schedule the
+ *     packet for transmission.
  */
 struct xsk_tx_metadata_ops {
 	void	(*tmo_request_timestamp)(void *priv);
 	u64	(*tmo_fill_timestamp)(void *priv);
 	void	(*tmo_request_checksum)(u16 csum_start, u16 csum_offset, void *priv);
+	void	(*tmo_request_launch_time)(u64 launch_time, void *priv);
 };
 
 #ifdef CONFIG_XDP_SOCKETS
@@ -170,6 +175,11 @@ static inline void xsk_tx_metadata_request(const struct xsk_tx_metadata *meta,
 		if (meta->flags & XDP_TXMD_FLAGS_CHECKSUM)
 			ops->tmo_request_checksum(meta->request.csum_start,
 						  meta->request.csum_offset, priv);
+
+	if (ops->tmo_request_launch_time)
+		if (meta->flags & XDP_TXMD_FLAGS_LAUNCH_TIME)
+			ops->tmo_request_launch_time(meta->request.launch_time,
+						     priv);
 }
 
 /**
diff --git a/include/net/xdp_sock_drv.h b/include/net/xdp_sock_drv.h
index 81e02de3f453..5b88559e956b 100644
--- a/include/net/xdp_sock_drv.h
+++ b/include/net/xdp_sock_drv.h
@@ -168,6 +168,7 @@ static inline void *xsk_buff_raw_get_data(struct xsk_buff_pool *pool, u64 addr)
 #define XDP_TXMD_FLAGS_VALID ( \
 		XDP_TXMD_FLAGS_TIMESTAMP | \
 		XDP_TXMD_FLAGS_CHECKSUM | \
+		XDP_TXMD_FLAGS_LAUNCH_TIME | \
 	0)
 
 static inline bool xsk_buff_valid_tx_metadata(struct xsk_tx_metadata *meta)
diff --git a/include/uapi/linux/if_xdp.h b/include/uapi/linux/if_xdp.h
index d31698410410..623d34e03981 100644
--- a/include/uapi/linux/if_xdp.h
+++ b/include/uapi/linux/if_xdp.h
@@ -123,6 +123,12 @@ struct xdp_options {
  */
 #define XDP_TXMD_FLAGS_CHECKSUM			(1 << 1)
 
+/* Request HW Time-Based Scheduling (TBS) offload to launch the packet at a
+ * pre-determined time. The time which the NIC should schedule the packet for
+ * transmission is communicated via launch_time field of struct xsk_tx_metadata.
+ */
+#define XDP_TXMD_FLAGS_LAUNCH_TIME		(1 << 2)
+
 /* AF_XDP offloads request. 'request' union member is consumed by the driver
  * when the packet is being transmitted. 'completion' union member is
  * filled by the driver when the transmit completion arrives.
@@ -138,6 +144,9 @@ struct xsk_tx_metadata {
 			__u16 csum_start;
 			/* Offset from csum_start where checksum should be stored. */
 			__u16 csum_offset;
+
+			/* XDP_TXMD_FLAGS_LAUNCH_TIME */
+			__u64 launch_time;
 		} request;
 
 		struct {
diff --git a/include/uapi/linux/netdev.h b/include/uapi/linux/netdev.h
index 48d5477a668c..db8b8618b29a 100644
--- a/include/uapi/linux/netdev.h
+++ b/include/uapi/linux/netdev.h
@@ -59,10 +59,13 @@ enum netdev_xdp_rx_metadata {
  *   by the driver.
  * @NETDEV_XSK_FLAGS_TX_CHECKSUM: L3 checksum HW offload is supported by the
  *   driver.
+ * @NETDEV_XSK_FLAGS_TX_LAUNCH_TIME: HW Time-Based Scheduling is supported by
+ *   the driver.
  */
 enum netdev_xsk_flags {
 	NETDEV_XSK_FLAGS_TX_TIMESTAMP = 1,
 	NETDEV_XSK_FLAGS_TX_CHECKSUM = 2,
+	NETDEV_XSK_FLAGS_TX_LAUNCH_TIME = 3,
 
 	/* private: */
 	NETDEV_XSK_FLAGS_MASK = 3,
diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c
index 10f2124e9e23..d001323b1d72 100644
--- a/net/core/netdev-genl.c
+++ b/net/core/netdev-genl.c
@@ -33,6 +33,8 @@ XDP_METADATA_KFUNC_xxx
 			xsk_features |= NETDEV_XSK_FLAGS_TX_TIMESTAMP;
 		if (netdev->xsk_tx_metadata_ops->tmo_request_checksum)
 			xsk_features |= NETDEV_XSK_FLAGS_TX_CHECKSUM;
+		if (netdev->xsk_tx_metadata_ops->tmo_request_launch_time)
+			xsk_features |= NETDEV_XSK_FLAGS_TX_LAUNCH_TIME;
 	}
 
 	if (nla_put_u32(rsp, NETDEV_A_DEV_IFINDEX, netdev->ifindex) ||
diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
index 281d49b4fca4..ad98ac6adb43 100644
--- a/net/xdp/xsk.c
+++ b/net/xdp/xsk.c
@@ -751,6 +751,9 @@ static struct sk_buff *xsk_build_skb(struct xdp_sock *xs,
 						goto free_err;
 				}
 			}
+
+			if (meta->flags & XDP_TXMD_FLAGS_LAUNCH_TIME)
+				skb->skb_mstamp_ns = meta->request.launch_time;
 		}
 	}
 
diff --git a/tools/include/uapi/linux/if_xdp.h b/tools/include/uapi/linux/if_xdp.h
index 638c606dfa74..80462125c5c3 100644
--- a/tools/include/uapi/linux/if_xdp.h
+++ b/tools/include/uapi/linux/if_xdp.h
@@ -123,6 +123,12 @@ struct xdp_options {
  */
 #define XDP_TXMD_FLAGS_CHECKSUM			(1 << 1)
 
+/* Request HW Time-Based Scheduling (TBS) offload to launch the packet at a
+ * pre-determined time. The time which the NIC should schedule the packet for
+ * transmission is communicated via launch_time field of struct xsk_tx_metadata.
+ */
+#define XDP_TXMD_FLAGS_LAUNCH_TIME		(1 << 2)
+
 /* AF_XDP offloads request. 'request' union member is consumed by the driver
  * when the packet is being transmitted. 'completion' union member is
  * filled by the driver when the transmit completion arrives.
@@ -138,6 +144,9 @@ struct xsk_tx_metadata {
 			__u16 csum_start;
 			/* Offset from csum_start where checksum should be stored. */
 			__u16 csum_offset;
+
+			/* XDP_TXMD_FLAGS_LAUNCH_TIME */
+			__u64 launch_time;
 		} request;
 
 		struct {
diff --git a/tools/include/uapi/linux/netdev.h b/tools/include/uapi/linux/netdev.h
index 48d5477a668c..db8b8618b29a 100644
--- a/tools/include/uapi/linux/netdev.h
+++ b/tools/include/uapi/linux/netdev.h
@@ -59,10 +59,13 @@ enum netdev_xdp_rx_metadata {
  *   by the driver.
  * @NETDEV_XSK_FLAGS_TX_CHECKSUM: L3 checksum HW offload is supported by the
  *   driver.
+ * @NETDEV_XSK_FLAGS_TX_LAUNCH_TIME: HW Time-Based Scheduling is supported by
+ *   the driver.
  */
 enum netdev_xsk_flags {
 	NETDEV_XSK_FLAGS_TX_TIMESTAMP = 1,
 	NETDEV_XSK_FLAGS_TX_CHECKSUM = 2,
+	NETDEV_XSK_FLAGS_TX_LAUNCH_TIME = 3,
 
 	/* private: */
 	NETDEV_XSK_FLAGS_MASK = 3,
diff --git a/tools/net/ynl/generated/netdev-user.c b/tools/net/ynl/generated/netdev-user.c
index 6283d87dad37..bb4136d64f57 100644
--- a/tools/net/ynl/generated/netdev-user.c
+++ b/tools/net/ynl/generated/netdev-user.c
@@ -61,6 +61,7 @@ const char *netdev_xdp_rx_metadata_str(enum netdev_xdp_rx_metadata value)
 static const char * const netdev_xsk_flags_strmap[] = {
 	[0] = "tx-timestamp",
 	[1] = "tx-checksum",
+	[2] = "launch-time"
 };
 
 const char *netdev_xsk_flags_str(enum netdev_xsk_flags value)
-- 
2.34.1

[xdp-hints] [PATCH bpf-next 2/3] net: stmmac: Add launch time support to XDP ZC

[Song Yoong Siang]

This patch enables launch time support to XDP zero copy via XDP Tx
metadata framework.

Signed-off-by: Song Yoong Siang <yoong.siang.song@intel.com>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac.h      |  2 ++
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 13 +++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
index 686c94c2e8a7..e8538af6e207 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
@@ -105,6 +105,8 @@ struct stmmac_metadata_request {
 	struct stmmac_priv *priv;
 	struct dma_desc *tx_desc;
 	bool *set_ic;
+	struct dma_edesc *edesc;
+	int tbs;
 };
 
 struct stmmac_xsk_tx_complete {
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index c2ac88aaffed..c33517d3850a 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -2465,9 +2465,20 @@ static u64 stmmac_xsk_fill_timestamp(void *_priv)
 	return 0;
 }
 
+static void stmmac_xsk_request_launch_time(u64 launch_time, void *_priv)
+{
+	struct stmmac_metadata_request *meta_req = _priv;
+	struct timespec64 ts = ns_to_timespec64(launch_time);
+
+	if ((meta_req->tbs & STMMAC_TBS_EN) && launch_time > 0)
+		stmmac_set_desc_tbs(meta_req->priv, meta_req->edesc, ts.tv_sec,
+				    ts.tv_nsec);
+}
+
 static const struct xsk_tx_metadata_ops stmmac_xsk_tx_metadata_ops = {
 	.tmo_request_timestamp		= stmmac_xsk_request_timestamp,
 	.tmo_fill_timestamp		= stmmac_xsk_fill_timestamp,
+	.tmo_request_launch_time	= stmmac_xsk_request_launch_time,
 };
 
 static bool stmmac_xdp_xmit_zc(struct stmmac_priv *priv, u32 queue, u32 budget)
@@ -2545,6 +2556,8 @@ static bool stmmac_xdp_xmit_zc(struct stmmac_priv *priv, u32 queue, u32 budget)
 		meta_req.priv = priv;
 		meta_req.tx_desc = tx_desc;
 		meta_req.set_ic = &set_ic;
+		meta_req.tbs = tx_q->tbs;
+		meta_req.edesc = &tx_q->dma_entx[entry];
 		xsk_tx_metadata_request(meta, &stmmac_xsk_tx_metadata_ops,
 					&meta_req);
 		if (set_ic) {
-- 
2.34.1

[xdp-hints] [PATCH bpf-next 3/3] selftests/bpf: Add launch time to xdp_hw_metadata

[Song Yoong Siang]

This patch adds launch time support to xdp_hw_metadata. User can configure
the delta of HW launch time to HW RX-time by using "-l" argument.

This patch is tested with stmmac on Intel Tiger Lake platform. Refer to
result below, the delta between pre-determined launch time and actual
transmit time is around 24 us.

$ sudo ./xdp_hw_metadata enp0s30f4
...
xsk_ring_cons__peek: 1
0x55fcb80ce7a8: rx_desc[0]->addr=80100 addr=80100 comp_addr=80100 EoP
No rx_hash err=-95
HW RX-time:   1677764507059055964 (sec:1677764507.0591) delta to User RX-time sec:0.0002 (237.548 usec)
XDP RX-time:   1677764507059280741 (sec:1677764507.0593) delta to User RX-time sec:0.0000 (12.771 usec)
0x55fcb80ce7a8: ping-pong with csum=5619 (want 8626) csum_start=34 csum_offset=6
HW RX-time:   1677764507059055964 (sec:1677764507.0591) delta to HW Launch-time sec:1.0000 (1000000.000 usec)
0x55fcb80ce7a8: complete tx idx=0 addr=18
HW Launch-time:   1677764508059055964 (sec:1677764508.0591) delta to HW TX-complete-time sec:0.0000 (24.235 usec)
HW TX-complete-time:   1677764508059080199 (sec:1677764508.0591) delta to User TX-complete-time sec:0.0054 (5423.263 usec)
XDP RX-time:   1677764507059280741 (sec:1677764507.0593) delta to User TX-complete-time sec:1.0052 (1005222.721 usec)
HW RX-time:   1677764507059055964 (sec:1677764507.0591) delta to HW TX-complete-time sec:1.0000 (1000024.235 usec)
0x55fcb80ce7a8: complete rx idx=128 addr=80100

$ sudo ./xdp_hw_metadata enp0s30f4 -l 10000000
...
xsk_ring_cons__peek: 1
0x5626d54de7a8: rx_desc[0]->addr=80100 addr=80100 comp_addr=80100 EoP
No rx_hash err=-95
HW RX-time:   1677764655807717783 (sec:1677764655.8077) delta to User RX-time sec:0.0002 (240.571 usec)
XDP RX-time:   1677764655807942983 (sec:1677764655.8079) delta to User RX-time sec:0.0000 (15.371 usec)
0x5626d54de7a8: ping-pong with csum=5619 (want 8626) csum_start=34 csum_offset=6
HW RX-time:   1677764655807717783 (sec:1677764655.8077) delta to HW Launch-time sec:0.0100 (10000.000 usec)
0x5626d54de7a8: complete tx idx=0 addr=18
HW Launch-time:   1677764655817717783 (sec:1677764655.8177) delta to HW TX-complete-time sec:0.0000 (23.965 usec)
HW TX-complete-time:   1677764655817741748 (sec:1677764655.8177) delta to User TX-complete-time sec:0.0003 (291.792 usec)
XDP RX-time:   1677764655807942983 (sec:1677764655.8079) delta to User TX-complete-time sec:0.0101 (10090.557 usec)
HW RX-time:   1677764655807717783 (sec:1677764655.8077) delta to HW TX-complete-time sec:0.0100 (10023.965 usec)
0x5626d54de7a8: complete rx idx=128 addr=80100

Signed-off-by: Song Yoong Siang <yoong.siang.song@intel.com>
---
 tools/testing/selftests/bpf/xdp_hw_metadata.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/bpf/xdp_hw_metadata.c b/tools/testing/selftests/bpf/xdp_hw_metadata.c
index 3291625ba4fb..ff1b2e5b0fce 100644
--- a/tools/testing/selftests/bpf/xdp_hw_metadata.c
+++ b/tools/testing/selftests/bpf/xdp_hw_metadata.c
@@ -13,6 +13,7 @@
  * - UDP 9091 packets trigger TX reply
  * - TX HW timestamp is requested and reported back upon completion
  * - TX checksum is requested
+ * - HW launch time is set for transmission
  */
 
 #include <test_progs.h>
@@ -61,6 +62,8 @@ int rxq;
 bool skip_tx;
 __u64 last_hw_rx_timestamp;
 __u64 last_xdp_rx_timestamp;
+__u64 last_launch_time;
+__u64 launch_time_offset = 1000000000; /* 1 second */
 
 void test__fail(void) { /* for network_helpers.c */ }
 
@@ -274,6 +277,8 @@ static bool complete_tx(struct xsk *xsk, clockid_t clock_id)
 	if (meta->completion.tx_timestamp) {
 		__u64 ref_tstamp = gettime(clock_id);
 
+		print_tstamp_delta("HW Launch-time", "HW TX-complete-time",
+				   last_launch_time, meta->completion.tx_timestamp);
 		print_tstamp_delta("HW TX-complete-time", "User TX-complete-time",
 				   meta->completion.tx_timestamp, ref_tstamp);
 		print_tstamp_delta("XDP RX-time", "User TX-complete-time",
@@ -371,6 +376,13 @@ static void ping_pong(struct xsk *xsk, void *rx_packet, clockid_t clock_id)
 	       xsk, ntohs(udph->check), ntohs(want_csum),
 	       meta->request.csum_start, meta->request.csum_offset);
 
+	/* Set launch time at launch_time_offset ns later than HW Rx-time */
+	meta->flags |= XDP_TXMD_FLAGS_LAUNCH_TIME;
+	last_launch_time = last_hw_rx_timestamp + launch_time_offset;
+	meta->request.launch_time = last_launch_time;
+	print_tstamp_delta("HW RX-time", "HW Launch-time",
+			   last_hw_rx_timestamp, meta->request.launch_time);
+
 	memcpy(data, rx_packet, len); /* don't share umem chunk for simplicity */
 	tx_desc->options |= XDP_TX_METADATA;
 	tx_desc->len = len;
@@ -595,6 +607,7 @@ static void print_usage(void)
 		"  -h    Display this help and exit\n\n"
 		"  -m    Enable multi-buffer XDP for larger MTU\n"
 		"  -r    Don't generate AF_XDP reply (rx metadata only)\n"
+		"  -l    Delta of HW launch time to HW RX-time in ns (default: 1s)\n"
 		"Generate test packets on the other machine with:\n"
 		"  echo -n xdp | nc -u -q1 <dst_ip> 9091\n";
 
@@ -605,7 +618,7 @@ static void read_args(int argc, char *argv[])
 {
 	int opt;
 
-	while ((opt = getopt(argc, argv, "chmr")) != -1) {
+	while ((opt = getopt(argc, argv, "chmrl:")) != -1) {
 		switch (opt) {
 		case 'c':
 			bind_flags &= ~XDP_USE_NEED_WAKEUP;
@@ -621,6 +634,9 @@ static void read_args(int argc, char *argv[])
 		case 'r':
 			skip_tx = true;
 			break;
+		case 'l':
+			launch_time_offset = atoll(optarg);
+			break;
 		case '?':
 			if (isprint(optopt))
 				fprintf(stderr, "Unknown option: -%c\n", optopt);
-- 
2.34.1

[xdp-hints] Re: [PATCH bpf-next 1/3] xsk: add launch time support to XDP Tx metadata

[Willem de Bruijn]

Song Yoong Siang wrote:
> This patch extends the XDP Tx metadata framework to include Time-Based
> Scheduling (TBS) support where the NIC will schedule a packet for
> transmission at a pre-determined time called launch time. The value of
> launch time is communicated from user space to Ethernet driver via
> launch_time field of struct xsk_tx_metadata.
> 
> Suggested-by: Stanislav Fomichev <sdf@google.com>
> Signed-off-by: Song Yoong Siang <yoong.siang.song@intel.com>
> ---
>  Documentation/netlink/specs/netdev.yaml      |  4 ++++
>  Documentation/networking/xsk-tx-metadata.rst |  5 +++++
>  include/net/xdp_sock.h                       | 10 ++++++++++
>  include/net/xdp_sock_drv.h                   |  1 +
>  include/uapi/linux/if_xdp.h                  |  9 +++++++++
>  include/uapi/linux/netdev.h                  |  3 +++
>  net/core/netdev-genl.c                       |  2 ++
>  net/xdp/xsk.c                                |  3 +++
>  tools/include/uapi/linux/if_xdp.h            |  9 +++++++++
>  tools/include/uapi/linux/netdev.h            |  3 +++
>  tools/net/ynl/generated/netdev-user.c        |  1 +
>  11 files changed, 50 insertions(+)
> 
> diff --git a/Documentation/netlink/specs/netdev.yaml b/Documentation/netlink/specs/netdev.yaml
> index 00439bcbd2e3..a602776bbfb4 100644
> --- a/Documentation/netlink/specs/netdev.yaml
> +++ b/Documentation/netlink/specs/netdev.yaml
> @@ -66,6 +66,10 @@ definitions:
>          name: tx-checksum
>          doc:
>            L3 checksum HW offload is supported by the driver.
> +      -
> +        name: launch-time
> +        doc:
> +          HW Time-Based Scheduling (TBS) is supported by the driver.

Can we avoid introducing another term? We already have too many:
launchtime, earliest delivery time (EDT), SO_TXTIME,
pacing offload, earliest txtime first (ETF).  

[xdp-hints] Re: [PATCH bpf-next 1/3] xsk: add launch time support to XDP Tx metadata

[Song, Yoong Siang]

On Friday, December 1, 2023 4:29 AM, Willem de Bruijn wrote:
>Song Yoong Siang wrote:
>> This patch extends the XDP Tx metadata framework to include Time-Based
>> Scheduling (TBS) support where the NIC will schedule a packet for
>> transmission at a pre-determined time called launch time. The value of
>> launch time is communicated from user space to Ethernet driver via
>> launch_time field of struct xsk_tx_metadata.
>>
>> Suggested-by: Stanislav Fomichev <sdf@google.com>
>> Signed-off-by: Song Yoong Siang <yoong.siang.song@intel.com>
>> ---
>>  Documentation/netlink/specs/netdev.yaml      |  4 ++++
>>  Documentation/networking/xsk-tx-metadata.rst |  5 +++++
>>  include/net/xdp_sock.h                       | 10 ++++++++++
>>  include/net/xdp_sock_drv.h                   |  1 +
>>  include/uapi/linux/if_xdp.h                  |  9 +++++++++
>>  include/uapi/linux/netdev.h                  |  3 +++
>>  net/core/netdev-genl.c                       |  2 ++
>>  net/xdp/xsk.c                                |  3 +++
>>  tools/include/uapi/linux/if_xdp.h            |  9 +++++++++
>>  tools/include/uapi/linux/netdev.h            |  3 +++
>>  tools/net/ynl/generated/netdev-user.c        |  1 +
>>  11 files changed, 50 insertions(+)
>>
>> diff --git a/Documentation/netlink/specs/netdev.yaml
>b/Documentation/netlink/specs/netdev.yaml
>> index 00439bcbd2e3..a602776bbfb4 100644
>> --- a/Documentation/netlink/specs/netdev.yaml
>> +++ b/Documentation/netlink/specs/netdev.yaml
>> @@ -66,6 +66,10 @@ definitions:
>>          name: tx-checksum
>>          doc:
>>            L3 checksum HW offload is supported by the driver.
>> +      -
>> +        name: launch-time
>> +        doc:
>> +          HW Time-Based Scheduling (TBS) is supported by the driver.
>
>Can we avoid introducing another term? We already have too many:
>launchtime, earliest delivery time (EDT), SO_TXTIME,
>pacing offload, earliest txtime first (ETF).
>

Sure. I will change TBS to ETF in my V2 so that it is aligned with etf command in tc application. 

[xdp-hints] Re: [PATCH bpf-next 1/3] xsk: add launch time support to XDP Tx metadata

[Jakub Kicinski]

On Fri,  1 Dec 2023 00:20:26 +0800 Song Yoong Siang wrote:
> +        name: launch-time
> +        doc:
> +          HW Time-Based Scheduling (TBS) is supported by the driver.

Does this mean fifo "gating" or HW can do reordering?

[xdp-hints] Re: [PATCH bpf-next 1/3] xsk: add launch time support to XDP Tx metadata

[Song, Yoong Siang]

On Saturday, December 2, 2023 11:29 AM, Jakub Kicinski wrote:
>On Fri,  1 Dec 2023 00:20:26 +0800 Song Yoong Siang wrote:
>> +        name: launch-time
>> +        doc:
>> +          HW Time-Based Scheduling (TBS) is supported by the driver.
>
>Does this mean fifo "gating" or HW can do reordering?

Yes, HW will do reordering according to the value of launch time.