diff mbox series

[bpf-next,10/10] selftests/xsk: adjust packet pacing for multi-buffer support

Message ID 20230512092043.3028-11-magnus.karlsson@gmail.com (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series seltests/xsk: prepare for AF_XDP multi-buffer testing | expand

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Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for bpf-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 8 this patch: 8
netdev/cc_maintainers warning 4 maintainers not CCed: mykolal@fb.com shuah@kernel.org linux-kselftest@vger.kernel.org jonathan.lemon@gmail.com
netdev/build_clang success Errors and warnings before: 8 this patch: 8
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 8 this patch: 8
netdev/checkpatch warning WARNING: line length of 81 exceeds 80 columns WARNING: line length of 96 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
bpf/vmtest-bpf-next-PR fail PR summary
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Commit Message

Magnus Karlsson May 12, 2023, 9:20 a.m. UTC 
From: Magnus Karlsson <magnus.karlsson@intel.com>

Modify the packet pacing algorithm so that it works with multi-buffer
packets. This algorithm makes sure we do not send too many buffers to
the receiving thread so that packets have to be dropped. The previous
algorithm made the assumption that each packet only consumes one
buffer, but that is not true anymore when multi-buffer support gets
added. Instead, we find out what the largest packet size is in the
packet stream and assume that each packet will consume this many
buffers. This is conservative and overly cautious as there might be
smaller packets in the stream that need fewer buffers per packet. But
it keeps the algorithm simple.

Also simplify it by removing the pthread conditional and just test if
there is enough space in the Rx thread before trying to send one more
batch. Also makes the tests run faster.

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
---
 tools/testing/selftests/bpf/xskxceiver.c | 48 ++++++++++++++----------
 tools/testing/selftests/bpf/xskxceiver.h |  2 +-
 2 files changed, 30 insertions(+), 20 deletions(-)
diff mbox series

Patch

diff --git a/tools/testing/selftests/bpf/xskxceiver.c b/tools/testing/selftests/bpf/xskxceiver.c
index c21c57a1f6e9..1986fb9fe797 100644
--- a/tools/testing/selftests/bpf/xskxceiver.c
+++ b/tools/testing/selftests/bpf/xskxceiver.c
@@ -555,6 +555,11 @@  static void pkt_set(struct xsk_umem_info *umem, struct pkt *pkt, int offset, u32
 		pkt->valid = true;
 }
 
+static u32 pkt_get_buffer_len(struct xsk_umem_info *umem, u32 len)
+{
+	return ceil_u32(len, umem->frame_size) * umem->frame_size;
+}
+
 static struct pkt_stream *pkt_stream_generate(struct xsk_umem_info *umem, u32 nb_pkts, u32 pkt_len)
 {
 	struct pkt_stream *pkt_stream;
@@ -564,6 +569,8 @@  static struct pkt_stream *pkt_stream_generate(struct xsk_umem_info *umem, u32 nb
 	if (!pkt_stream)
 		exit_with_error(ENOMEM);
 
+	pkt_stream->nb_pkts = nb_pkts;
+	pkt_stream->max_pkt_len = pkt_len;
 	for (i = 0; i < nb_pkts; i++) {
 		struct pkt *pkt = &pkt_stream->pkts[i];
 
@@ -661,10 +668,14 @@  static void __pkt_stream_generate_custom(struct ifobject *ifobj,
 		exit_with_error(ENOMEM);
 
 	for (i = 0; i < nb_pkts; i++) {
-		pkt_stream->pkts[i].offset = pkts[i].offset;
-		pkt_stream->pkts[i].len = pkts[i].len;
-		pkt_stream->pkts[i].pkt_nb = i;
-		pkt_stream->pkts[i].valid = pkts[i].valid;
+		struct pkt *pkt = &pkt_stream->pkts[i];
+
+		pkt->offset = pkts[i].offset;
+		pkt->len = pkts[i].len;
+		pkt->pkt_nb = i;
+		pkt->valid = pkts[i].valid;
+		if (pkt->len > pkt_stream->max_pkt_len)
+			pkt_stream->max_pkt_len = pkt->len;
 	}
 
 	ifobj->pkt_stream = pkt_stream;
@@ -926,8 +937,6 @@  static int receive_pkts(struct test_spec *test, struct pollfd *fds)
 
 		pthread_mutex_lock(&pacing_mutex);
 		pkts_in_flight -= pkts_sent;
-		if (pkts_in_flight < umem->num_frames)
-			pthread_cond_signal(&pacing_cond);
 		pthread_mutex_unlock(&pacing_mutex);
 		pkts_sent = 0;
 	}
@@ -938,10 +947,18 @@  static int receive_pkts(struct test_spec *test, struct pollfd *fds)
 static int __send_pkts(struct ifobject *ifobject, struct pollfd *fds, bool timeout)
 {
 	struct xsk_socket_info *xsk = ifobject->xsk;
+	struct xsk_umem_info *umem = ifobject->umem;
+	u32 i, idx = 0, valid_pkts = 0, buffer_len;
 	bool use_poll = ifobject->use_poll;
-	u32 i, idx = 0, valid_pkts = 0;
 	int ret;
 
+	buffer_len = pkt_get_buffer_len(umem, ifobject->pkt_stream->max_pkt_len);
+	/* pkts_in_flight might be negative if many invalid packets are sent */
+	if (pkts_in_flight >= (int)((umem_size(umem) - BATCH_SIZE * buffer_len) / buffer_len)) {
+		kick_tx(xsk);
+		return TEST_CONTINUE;
+	}
+
 	while (xsk_ring_prod__reserve(&xsk->tx, BATCH_SIZE, &idx) < BATCH_SIZE) {
 		if (use_poll) {
 			ret = poll(fds, 1, POLL_TMOUT);
@@ -972,7 +989,7 @@  static int __send_pkts(struct ifobject *ifobject, struct pollfd *fds, bool timeo
 		if (!pkt)
 			break;
 
-		tx_desc->addr = pkt_get_addr(pkt, ifobject->umem);
+		tx_desc->addr = pkt_get_addr(pkt, umem);
 		tx_desc->len = pkt->len;
 		if (pkt->valid) {
 			valid_pkts++;
@@ -982,11 +999,6 @@  static int __send_pkts(struct ifobject *ifobject, struct pollfd *fds, bool timeo
 
 	pthread_mutex_lock(&pacing_mutex);
 	pkts_in_flight += valid_pkts;
-	/* pkts_in_flight might be negative if many invalid packets are sent */
-	if (pkts_in_flight >= (int)(ifobject->umem->num_frames - BATCH_SIZE)) {
-		kick_tx(xsk);
-		pthread_cond_wait(&pacing_cond, &pacing_mutex);
-	}
 	pthread_mutex_unlock(&pacing_mutex);
 
 	xsk_ring_prod__submit(&xsk->tx, i);
@@ -1032,9 +1044,11 @@  static int send_pkts(struct test_spec *test, struct ifobject *ifobject)
 
 	while (pkt_stream->current_pkt_nb < pkt_stream->nb_pkts) {
 		ret = __send_pkts(ifobject, &fds, timeout);
+		if (ret == TEST_CONTINUE && !test->fail)
+			continue;
 		if ((ret || test->fail) && !timeout)
 			return TEST_FAILURE;
-		else if (ret == TEST_PASS && timeout)
+		if (ret == TEST_PASS && timeout)
 			return ret;
 	}
 
@@ -1319,12 +1333,8 @@  static void *worker_testapp_validate_rx(void *arg)
 
 	if (!err && ifobject->validation_func)
 		err = ifobject->validation_func(ifobject);
-	if (err) {
+	if (err)
 		report_failure(test);
-		pthread_mutex_lock(&pacing_mutex);
-		pthread_cond_signal(&pacing_cond);
-		pthread_mutex_unlock(&pacing_mutex);
-	}
 
 	pthread_exit(NULL);
 }
diff --git a/tools/testing/selftests/bpf/xskxceiver.h b/tools/testing/selftests/bpf/xskxceiver.h
index 00862732e751..aaf27e067640 100644
--- a/tools/testing/selftests/bpf/xskxceiver.h
+++ b/tools/testing/selftests/bpf/xskxceiver.h
@@ -121,6 +121,7 @@  struct pkt_stream {
 	u32 nb_pkts;
 	u32 current_pkt_nb;
 	struct pkt *pkts;
+	u32 max_pkt_len;
 };
 
 struct ifobject;
@@ -173,7 +174,6 @@  struct test_spec {
 
 pthread_barrier_t barr;
 pthread_mutex_t pacing_mutex = PTHREAD_MUTEX_INITIALIZER;
-pthread_cond_t pacing_cond = PTHREAD_COND_INITIALIZER;
 
 int pkts_in_flight;