[bpf-next,v4,3/4] net: stmmac: Add launch time support to XDP ZC

Commit Message

Song Yoong Siang Jan. 6, 2025, 1:56 p.m. UTC

Enable launch time (Time-Based Scheduling) support to XDP zero copy via XDP
Tx metadata framework.

This patch is tested with tools/testing/selftests/bpf/xdp_hw_metadata on
Intel Tiger Lake platform. Below are the test steps and result.

Test Steps:
1. Add mqprio qdisc:
   $ sudo tc qdisc add dev enp0s30f4 handle 8001: parent root mqprio num_tc
     4 map 0 1 2 3 3 3 3 3 3 3 3 3 3 3 3 3 queues 1@0 1@1 1@2 1@3 hw 0

2. Enable launch time hardware offload on hardware queue 1:
   $ sudo tc qdisc replace dev enp0s30f4 parent 8001:2 etf offload clockid
     CLOCK_TAI delta 500000

3. Add an ingress qdisc:
   $ sudo tc qdisc add dev enp0s30f4 ingress

4. Add a flower filter to route incoming packet with VLAN priority 1 into
   hardware queue 1:
   $ sudo tc filter add dev enp0s30f4 parent ffff: protocol 802.1Q flower
     vlan_prio 1 hw_tc 1

5. Enable VLAN tag stripping:
   $ sudo ethtool -K enp0s30f4 rxvlan on

6. Start xdp_hw_metadata selftest application:
   $ sudo ./xdp_hw_metadata enp0s30f4 -l 1000000000

7. Send an UDP packet with VLAN priority 1 to port 9091 of DUT.

When launch time is set to 1s in the future, the delta between launch time
and transmit hardware timestamp is equal to 16.963us, as shown in result
below:
  0x55b5864717a8: rx_desc[4]->addr=88100 addr=88100 comp_addr=88100 EoP
  No rx_hash, err=-95
  HW RX-time:   1734579065767717328 (sec:1734579065.7677) delta to User RX-time sec:0.0004 (375.624 usec)
  XDP RX-time:   1734579065768004454 (sec:1734579065.7680) delta to User RX-time sec:0.0001 (88.498 usec)
  No rx_vlan_tci or rx_vlan_proto, err=-95
  0x55b5864717a8: ping-pong with csum=5619 (want 0000) csum_start=34 csum_offset=6
  HW RX-time:   1734579065767717328 (sec:1734579065.7677) delta to HW Launch-time sec:1.0000 (1000000.000 usec)
  0x55b5864717a8: complete tx idx=4 addr=4018
  HW Launch-time:   1734579066767717328 (sec:1734579066.7677) delta to HW TX-complete-time sec:0.0000 (16.963 usec)
  HW TX-complete-time:   1734579066767734291 (sec:1734579066.7677) delta to User TX-complete-time sec:0.0001 (130.408 usec)
  XDP RX-time:   1734579065768004454 (sec:1734579065.7680) delta to User TX-complete-time sec:0.9999 (999860.245 usec)
  HW RX-time:   1734579065767717328 (sec:1734579065.7677) delta to HW TX-complete-time sec:1.0000 (1000016.963 usec)
  0x55b5864717a8: complete rx idx=132 addr=88100

Signed-off-by: Song Yoong Siang <[e-mail]>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac.h      |  2 ++
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 13 +++++++++++++
 2 files changed, 15 insertions(+)

Comments

Stanislav Fomichev Jan. 7, 2025, 5:07 p.m. UTC | #1

On 01/06, Song Yoong Siang wrote:
> Enable launch time (Time-Based Scheduling) support to XDP zero copy via XDP
> Tx metadata framework.
> 
> This patch is tested with tools/testing/selftests/bpf/xdp_hw_metadata on
> Intel Tiger Lake platform. Below are the test steps and result.
> 
> Test Steps:
> 1. Add mqprio qdisc:
>    $ sudo tc qdisc add dev enp0s30f4 handle 8001: parent root mqprio num_tc
>      4 map 0 1 2 3 3 3 3 3 3 3 3 3 3 3 3 3 queues 1@0 1@1 1@2 1@3 hw 0
> 
> 2. Enable launch time hardware offload on hardware queue 1:
>    $ sudo tc qdisc replace dev enp0s30f4 parent 8001:2 etf offload clockid
>      CLOCK_TAI delta 500000
> 
> 3. Add an ingress qdisc:
>    $ sudo tc qdisc add dev enp0s30f4 ingress
> 
> 4. Add a flower filter to route incoming packet with VLAN priority 1 into
>    hardware queue 1:
>    $ sudo tc filter add dev enp0s30f4 parent ffff: protocol 802.1Q flower
>      vlan_prio 1 hw_tc 1
> 
> 5. Enable VLAN tag stripping:
>    $ sudo ethtool -K enp0s30f4 rxvlan on
> 
> 6. Start xdp_hw_metadata selftest application:
>    $ sudo ./xdp_hw_metadata enp0s30f4 -l 1000000000
> 
> 7. Send an UDP packet with VLAN priority 1 to port 9091 of DUT.

Tangential: I wonder whether we can add the setup steps to the
xdp_hw_metadata tool? It is useful to have one command to run that
takes care of all the details. Same way it already enables HW
tstamping.. 

Or, if not the full setup, some kind of detection we can signal to the
user that some things might be missing?

Patch

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
index 1d86439b8a14..c80462d42989 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
@@ -106,6 +106,8 @@  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 c81ea8cdfe6e..3a083e3684ed 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -2445,9 +2445,20 @@  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)
+		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)
@@ -2531,6 +2542,8 @@  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) {