[xdp-hints] [PATCH bpf-next v4 2/4] selftests/bpf: Add Launch Time request to xdp_hw_metadata

[Song Yoong Siang <yoong.siang.song@intel.com>]

Add Launch Time hw offload request to xdp_hw_metadata. User can configure
the delta of launch time to HW RX-time by using "-l" argument. The default
delta is 100,000,000 nanosecond.

Signed-off-by: Song Yoong Siang <yoong.siang.song@intel.com>
---
 tools/testing/selftests/bpf/xdp_hw_metadata.c | 30 +++++++++++++++++--
 1 file changed, 27 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/bpf/xdp_hw_metadata.c b/tools/testing/selftests/bpf/xdp_hw_metadata.c
index 6f7b15d6c6ed..795c1d14e02d 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
+ * - TX launch time HW offload is requested for transmission
  */
 
 #include <test_progs.h>
@@ -64,6 +65,8 @@ int rxq;
 bool skip_tx;
 __u64 last_hw_rx_timestamp;
 __u64 last_xdp_rx_timestamp;
+__u64 last_launch_time;
+__u64 launch_time_delta_to_hw_rx_timestamp = 100000000; /* 0.1 second */
 
 void test__fail(void) { /* for network_helpers.c */ }
 
@@ -298,6 +301,8 @@ 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",
@@ -395,6 +400,14 @@ 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 the value of launch time */
+	meta->flags |= XDP_TXMD_FLAGS_LAUNCH_TIME;
+	meta->request.launch_time = last_hw_rx_timestamp +
+				    launch_time_delta_to_hw_rx_timestamp;
+	last_launch_time = meta->request.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;
@@ -402,10 +415,14 @@ static void ping_pong(struct xsk *xsk, void *rx_packet, clockid_t clock_id)
 	xsk_ring_prod__submit(&xsk->tx, 1);
 }
 
+#define SLEEP_PER_ITERATION_IN_US 10
+#define SLEEP_PER_ITERATION_IN_NS (SLEEP_PER_ITERATION_IN_US * 1000)
+#define MAX_ITERATION(x) (((x) / SLEEP_PER_ITERATION_IN_NS) + 500)
 static int verify_metadata(struct xsk *rx_xsk, int rxq, int server_fd, clockid_t clock_id)
 {
 	const struct xdp_desc *rx_desc;
 	struct pollfd fds[rxq + 1];
+	int max_iterations;
 	__u64 comp_addr;
 	__u64 addr;
 	__u32 idx = 0;
@@ -418,6 +435,9 @@ static int verify_metadata(struct xsk *rx_xsk, int rxq, int server_fd, clockid_t
 		fds[i].revents = 0;
 	}
 
+	/* Calculate max iterations to wait for transmit completion */
+	max_iterations = MAX_ITERATION(launch_time_delta_to_hw_rx_timestamp);
+
 	fds[rxq].fd = server_fd;
 	fds[rxq].events = POLLIN;
 	fds[rxq].revents = 0;
@@ -477,10 +497,10 @@ static int verify_metadata(struct xsk *rx_xsk, int rxq, int server_fd, clockid_t
 					if (ret)
 						printf("kick_tx ret=%d\n", ret);
 
-					for (int j = 0; j < 500; j++) {
+					for (int j = 0; j < max_iterations; j++) {
 						if (complete_tx(xsk, clock_id))
 							break;
-						usleep(10);
+						usleep(SLEEP_PER_ITERATION_IN_US);
 					}
 				}
 			}
@@ -608,6 +628,7 @@ 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 launch time to HW RX-time in ns (default: 100,000,000ns)\n"
 		"Generate test packets on the other machine with:\n"
 		"  echo -n xdp | nc -u -q1 <dst_ip> 9091\n";
 
@@ -618,7 +639,7 @@ 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;
@@ -634,6 +655,9 @@ static void read_args(int argc, char *argv[])
 		case 'r':
 			skip_tx = true;
 			break;
+		case 'l':
+			launch_time_delta_to_hw_rx_timestamp = atoll(optarg);
+			break;
 		case '?':
 			if (isprint(optopt))
 				fprintf(stderr, "Unknown option: -%c\n", optopt);
-- 
2.34.1