lib/sock: Add option to enable or disable quick ACK

TCP delayed ACK can be disabled or enabled by enabling or disabling
quick ACK, respectively.

The recently added spdk_sock_impl_opts is helpful for sock library
to control quick ACK.

Hence this patch adds and uses an option enable_quickack. The option
is effective only for the POSIX sock module.

We have spdk_sock_opts now too but spdk_sock_impl_opts will be better
for this case.

This option is not supported on FreeBSD. FreeBSD users can set the
option globally via sysctl if desired.

Signed-off-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Change-Id: Ic89620267acce5872dc8ecaf7a99bb70ae97e993
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/3603
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>

doc/jsonrpc.md

@@ -6608,6 +6608,7 @@ recv_buf_size           | Optional | number      | Size of socket receive buffer
 send_buf_size           | Optional | number      | Size of socket send buffer in bytes
 enable_recv_pipe        | Optional | boolean     | Enable or disable receive pipe
 enable_zerocopy_send    | Optional | boolean     | Enable or disable zero copy on send
+enable_quick_ack        | Optional | boolean     | Enable or disable quick ACK
 
 ### Response
 
@@ -6626,8 +6627,9 @@ Example request:
     "impl_name": "posix",
     "recv_buf_size": 2097152,
     "send_buf_size": 2097152,
-    "enable_recv_pipe": false
+    "enable_recv_pipe": false,
-    "enable_zerocopy_send": true
+    "enable_zerocopy_send": true,
+    "enable_quick_ack": false
   }
 }
 ~~~

include/spdk/sock.h

@@ -107,6 +107,11 @@ struct spdk_sock_impl_opts {
 	 * Enable or disable use of zero copy flow on send. Used by posix socket module.
 	 */
 	bool enable_zerocopy_send;
+
+	/**
+	 * Enable or disable quick ACK. Used by posix socket module.
+	 */
+	bool enable_quickack;
 };
 
 /**

lib/sock/sock_rpc.c

@@ -75,6 +75,7 @@ rpc_sock_impl_get_options(struct spdk_jsonrpc_request *request,
 	spdk_json_write_named_uint32(w, "send_buf_size", sock_opts.send_buf_size);
 	spdk_json_write_named_bool(w, "enable_recv_pipe", sock_opts.enable_recv_pipe);
 	spdk_json_write_named_bool(w, "enable_zerocopy_send", sock_opts.enable_zerocopy_send);
+	spdk_json_write_named_bool(w, "enable_quickack", sock_opts.enable_quickack);
 	spdk_json_write_object_end(w);
 	spdk_jsonrpc_end_result(request, w);
 	free(impl_name);
@@ -108,6 +109,10 @@ static const struct spdk_json_object_decoder rpc_sock_impl_set_opts_decoders[] =
 		"enable_zerocopy_send", offsetof(struct spdk_rpc_sock_impl_set_opts, sock_opts.enable_zerocopy_send),
 		spdk_json_decode_bool, true
 	},
+	{
+		"enable_quickack", offsetof(struct spdk_rpc_sock_impl_set_opts, sock_opts.enable_quickack),
+		spdk_json_decode_bool, true
+	},
 };
 
 static void

module/sock/posix/posix.c

@@ -83,7 +83,8 @@ static struct spdk_sock_impl_opts g_spdk_posix_sock_impl_opts = {
 	.recv_buf_size = MIN_SO_RCVBUF_SIZE,
 	.send_buf_size = MIN_SO_SNDBUF_SIZE,
 	.enable_recv_pipe = true,
-	.enable_zerocopy_send = true
+	.enable_zerocopy_send = true,
+	.enable_quickack = false,
 };
 
 static int
@@ -313,9 +314,9 @@ static struct spdk_posix_sock *
 posix_sock_alloc(int fd, bool enable_zero_copy)
 {
 	struct spdk_posix_sock *sock;
-#ifdef SPDK_ZEROCOPY
+#if defined(SPDK_ZEROCOPY) || defined(__linux__)
-	int rc;
 	int flag;
+	int rc;
 #endif
 
 	sock = calloc(1, sizeof(*sock));
@@ -326,19 +327,31 @@ posix_sock_alloc(int fd, bool enable_zero_copy)
 
 	sock->fd = fd;
 
-#ifdef SPDK_ZEROCOPY
+#if defined(SPDK_ZEROCOPY)
+	flag = 1;
+
 	if (!enable_zero_copy || !g_spdk_posix_sock_impl_opts.enable_zerocopy_send) {
 		return sock;
 	}
 
 	/* Try to turn on zero copy sends */
-	flag = 1;
 	rc = setsockopt(sock->fd, SOL_SOCKET, SO_ZEROCOPY, &flag, sizeof(flag));
 	if (rc == 0) {
 		sock->zcopy = true;
 	}
 #endif
 
+#if defined(__linux__)
+	flag = 1;
+
+	if (g_spdk_posix_sock_impl_opts.enable_quickack) {
+		rc = setsockopt(sock->fd, IPPROTO_TCP, TCP_QUICKACK, &flag, sizeof(flag));
+		if (rc != 0) {
+			SPDK_ERRLOG("quickack was failed to set\n");
+		}
+	}
+#endif
+
 	return sock;
 }
 
@@ -1338,6 +1351,7 @@ posix_sock_impl_get_opts(struct spdk_sock_impl_opts *opts, size_t *len)
 	GET_FIELD(send_buf_size);
 	GET_FIELD(enable_recv_pipe);
 	GET_FIELD(enable_zerocopy_send);
+	GET_FIELD(enable_quickack);
 
 #undef GET_FIELD
 #undef FIELD_OK
@@ -1366,6 +1380,7 @@ posix_sock_impl_set_opts(const struct spdk_sock_impl_opts *opts, size_t len)
 	SET_FIELD(send_buf_size);
 	SET_FIELD(enable_recv_pipe);
 	SET_FIELD(enable_zerocopy_send);
+	SET_FIELD(enable_quickack);
 
 #undef SET_FIELD
 #undef FIELD_OK

scripts/rpc.py

@@ -2401,7 +2401,8 @@ Format: 'user:u1 secret:s1 muser:mu1 msecret:ms1,user:u2 secret:s2 muser:mu2 mse
                                        recv_buf_size=args.recv_buf_size,
                                        send_buf_size=args.send_buf_size,
                                        enable_recv_pipe=args.enable_recv_pipe,
-                                       enable_zerocopy_send=args.enable_zerocopy_send)
+                                       enable_zerocopy_send=args.enable_zerocopy_send,
+                                       enable_quickack=args.enable_quickack)
 
     p = subparsers.add_parser('sock_impl_set_options', help="""Set options of socket layer implementation""")
     p.add_argument('-i', '--impl', help='Socket implementation name, e.g. posix', required=True)
@@ -2415,7 +2416,12 @@ Format: 'user:u1 secret:s1 muser:mu1 msecret:ms1,user:u2 secret:s2 muser:mu2 mse
                    action='store_true', dest='enable_zerocopy_send')
     p.add_argument('--disable-zerocopy-send', help='Disable zerocopy on send',
                    action='store_false', dest='enable_zerocopy_send')
-    p.set_defaults(func=sock_impl_set_options, enable_recv_pipe=None, enable_zerocopy_send=None)
+    p.add_argument('--enable-quickack', help='Enable quick ACK',
+                   action='store_true', dest='enable_quickack')
+    p.add_argument('--disable-quickack', help='Disable quick ACK',
+                   action='store_false', dest='enable_quickack')
+    p.set_defaults(func=sock_impl_set_options, enable_recv_pipe=None, enable_zerocopy_send=None,
+                   enable_quickack=None)
 
     def check_called_name(name):
         if name in deprecated_aliases:

scripts/rpc/sock.py

@@ -16,7 +16,8 @@ def sock_impl_set_options(client,
                           recv_buf_size=None,
                           send_buf_size=None,
                           enable_recv_pipe=None,
-                          enable_zerocopy_send=None):
+                          enable_zerocopy_send=None,
+                          enable_quickack=None):
     """Set parameters for the socket layer implementation.
 
     Args:
@@ -25,6 +26,7 @@ def sock_impl_set_options(client,
         send_buf_size: size of socket send buffer in bytes (optional)
         enable_recv_pipe: enable or disable receive pipe (optional)
         enable_zerocopy_send: enable or disable zerocopy on send (optional)
+        enable_quickack: enable or disable quickack (optional)
     """
     params = {}
 
@@ -37,5 +39,7 @@ def sock_impl_set_options(client,
         params['enable_recv_pipe'] = enable_recv_pipe
     if enable_zerocopy_send is not None:
         params['enable_zerocopy_send'] = enable_zerocopy_send
+    if enable_quickack is not None:
+        params['enable_quickack'] = enable_quickack
 
     return client.call('sock_impl_set_options', params)