posix: Group connections of sock group on host side based on placement_id

On host side the connections are created and then added to thread's
poll group. Those connections could use different NIC queues underneath.
To route all connections of poll group through single queue a unique
placement id is chosen as group_placement_id and each socket of poll
group is marked with group_placment_id using getsockopt(SO_MARK) option.

The driver could use so_mark value of skb to determine the queue to use.

Change-Id: I06bda777fe07a62133b80b2491fa7772150b3b5d
Signed-off-by: Sudheer Mogilappagari <sudheer.mogilappagari@intel.com>
Signed-off-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/6160
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Community-CI: Mellanox Build Bot
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>

CHANGELOG.md

@@ -174,6 +174,11 @@ bool to int. We can use RPC to configure different value of `enable_placement_id
 Then we can leverage SO_INCOMING_CPU to get placement_id, which aims to utilize
 CPU cache locality, enabled by setting enable_placement_id=2.
 
+A new socket placement mode called PLACEMENT_MARK has been added. Some NICs allow
+sockets to be marked using the SO_MARK socket option as a hint for which hardware
+queue they should be associated with. This mode leverages that by setting the same
+value for all sockets within a poll group.
+
 ### thread
 
 A new API `spdk_io_channel_get_io_device` was added to get the io_device for the specified

include/spdk/sock.h

@@ -84,6 +84,7 @@ enum spdk_placement_mode {
 	PLACEMENT_NONE,
 	PLACEMENT_NAPI,
 	PLACEMENT_CPU,
+	PLACEMENT_MARK,
 };
 
 /**

include/spdk_internal/sock.h

@@ -284,6 +284,7 @@ spdk_sock_get_placement_id(int fd, enum spdk_placement_mode mode, int *placement
 	switch (mode) {
 	case PLACEMENT_NONE:
 		break;
+	case PLACEMENT_MARK:
 	case PLACEMENT_NAPI: {
 #if defined(SO_INCOMING_NAPI_ID)
 		socklen_t len = sizeof(int);

module/sock/posix/posix.c

@@ -82,6 +82,7 @@ struct spdk_posix_sock_group_impl {
 	struct spdk_sock_group_impl	base;
 	int				fd;
 	struct spdk_pending_events_list	pending_events;
+	int				placement_id;
 };
 
 static struct spdk_sock_impl_opts g_spdk_posix_sock_impl_opts = {
@@ -368,6 +369,11 @@ posix_sock_alloc(int fd, bool enable_zero_copy)
 
 	spdk_sock_get_placement_id(sock->fd, g_spdk_posix_sock_impl_opts.enable_placement_id,
 				   &sock->placement_id);
+
+	if (g_spdk_posix_sock_impl_opts.enable_placement_id == PLACEMENT_MARK) {
+		/* Save placement_id */
+		spdk_sock_map_insert(&g_map, sock->placement_id, NULL);
+	}
 #endif
 
 	return sock;
@@ -1148,14 +1154,69 @@ posix_sock_group_impl_create(void)
 
 	group_impl->fd = fd;
 	TAILQ_INIT(&group_impl->pending_events);
+	group_impl->placement_id = -1;
 
 	if (g_spdk_posix_sock_impl_opts.enable_placement_id == PLACEMENT_CPU) {
 		spdk_sock_map_insert(&g_map, spdk_env_get_current_core(), &group_impl->base);
+		group_impl->placement_id = spdk_env_get_current_core();
 	}
 
 	return &group_impl->base;
 }
 
+static void
+posix_sock_mark(struct spdk_posix_sock_group_impl *group, struct spdk_posix_sock *sock,
+		int placement_id)
+{
+#if defined(SO_MARK)
+	int rc;
+
+	rc = setsockopt(sock->fd, SOL_SOCKET, SO_MARK,
+			&placement_id, sizeof(placement_id));
+	if (rc != 0) {
+		/* Not fatal */
+		SPDK_ERRLOG("Error setting SO_MARK\n");
+		return;
+	}
+
+	rc = spdk_sock_map_insert(&g_map, placement_id, &group->base);
+	if (rc != 0) {
+		/* Not fatal */
+		SPDK_ERRLOG("Failed to insert sock group into map: %d\n", rc);
+		return;
+	}
+
+	sock->placement_id = placement_id;
+#endif
+}
+
+static void
+posix_sock_update_mark(struct spdk_sock_group_impl *_group, struct spdk_sock *_sock)
+{
+	struct spdk_posix_sock_group_impl *group = __posix_group_impl(_group);
+
+	if (group->placement_id == -1) {
+		group->placement_id = spdk_sock_map_find_free(&g_map);
+
+		/* If a free placement id is found, update existing sockets in this group */
+		if (group->placement_id != -1) {
+			struct spdk_sock  *sock, *tmp;
+
+			TAILQ_FOREACH_SAFE(sock, &_group->socks, link, tmp) {
+				posix_sock_mark(group, __posix_sock(sock), group->placement_id);
+			}
+		}
+	}
+
+	if (group->placement_id != -1) {
+		/*
+		 * group placement id is already determined for this poll group.
+		 * Mark socket with group's placement id.
+		 */
+		posix_sock_mark(group, __posix_sock(_sock), group->placement_id);
+	}
+}
+
 static int
 posix_sock_group_impl_add_sock(struct spdk_sock_group_impl *_group, struct spdk_sock *_sock)
 {
@@ -1193,10 +1254,12 @@ posix_sock_group_impl_add_sock(struct spdk_sock_group_impl *_group, struct spdk_
 		TAILQ_INSERT_TAIL(&group->pending_events, sock, link);
 	}
 
-	if (sock->placement_id != -1) {
+	if (g_spdk_posix_sock_impl_opts.enable_placement_id == PLACEMENT_MARK) {
+		posix_sock_update_mark(_group, _sock);
+	} else if (sock->placement_id != -1) {
 		rc = spdk_sock_map_insert(&g_map, sock->placement_id, &group->base);
 		if (rc != 0) {
-			SPDK_ERRLOG("Failed to insert sock group into map: %d", rc);
+			SPDK_ERRLOG("Failed to insert sock group into map: %d\n", rc);
 			/* Do not treat this as an error. The system will continue running. */
 		}
 	}