Goodbye delay_frames! stateless_mode is the new delay_frames=0

config.def.h

@@ -794,6 +794,9 @@ static const bool pause_nonactive = true;
  * It is measured in seconds. A value of 0 disables autosave. */
 static const unsigned autosave_interval = 0;
 
+/* Netplay without savestates/rewind */
+static const bool netplay_stateless_mode = false;
+
 /* When being client over netplay, use keybinds for
  * user 1 rather than user 2. */
 static const bool netplay_client_swap_input = true;

configuration.c

@@ -718,6 +718,7 @@ static int populate_settings_bool(settings_t *settings, struct config_bool_setti
    SETTING_BOOL("all_users_control_menu",        &settings->input.all_users_control_menu, true, all_users_control_menu, false);
    SETTING_BOOL("menu_swap_ok_cancel_buttons",                 &settings->input.menu_swap_ok_cancel_buttons, true, menu_swap_ok_cancel_buttons, false);
 #ifdef HAVE_NETWORKING
+   SETTING_BOOL("netplay_stateless_mode",        &settings->netplay.stateless_mode, false, netplay_stateless_mode, false);
    SETTING_BOOL("netplay_client_swap_input",     &settings->netplay.swap_input, true, netplay_client_swap_input, false);
 #endif
    SETTING_BOOL("input_descriptor_label_show",   &settings->input.input_descriptor_label_show, true, input_descriptor_label_show, false);
@@ -947,7 +948,6 @@ static int populate_settings_int(settings_t *settings, struct config_int_setting
    SETTING_INT("state_slot",                   (unsigned*)&settings->state_slot, false, 0 /* TODO */, false);
 #ifdef HAVE_NETWORKING
    SETTING_INT("netplay_ip_port",              &settings->netplay.port,         true, RARCH_DEFAULT_PORT, false);
-   SETTING_INT("netplay_delay_frames",         &settings->netplay.delay_frames, true, netplay_delay_frames, false);
    SETTING_INT("netplay_check_frames",         &settings->netplay.check_frames, true, netplay_check_frames, false);
 #endif
 #ifdef HAVE_LANGEXTRA
@@ -1856,8 +1856,8 @@ static bool config_load_file(const char *path, bool set_defaults,
    }
 
 #ifdef HAVE_NETWORKING
-   if (!retroarch_override_setting_is_set(RARCH_OVERRIDE_SETTING_NETPLAY_DELAY_FRAMES, NULL))
-      CONFIG_GET_INT_BASE(conf, settings, netplay.delay_frames, "netplay_delay_frames");
+   if (!retroarch_override_setting_is_set(RARCH_OVERRIDE_SETTING_NETPLAY_STATELESS_MODE, NULL))
+      CONFIG_GET_BOOL_BASE(conf, settings, netplay.stateless_mode, "netplay_stateless_mode");
    if (!retroarch_override_setting_is_set(RARCH_OVERRIDE_SETTING_NETPLAY_CHECK_FRAMES, NULL))
       CONFIG_GET_INT_BASE(conf, settings, netplay.check_frames, "netplay_check_frames");
    if (!retroarch_override_setting_is_set(RARCH_OVERRIDE_SETTING_NETPLAY_IP_PORT, NULL))

configuration.h

@@ -401,7 +401,7 @@ typedef struct settings
    {
       char server[255];
       unsigned port;
-      unsigned delay_frames;
+      bool stateless_mode;
       unsigned check_frames;
       bool swap_input;
       bool nat_traversal;

intl/msg_hash_lbl.h

@@ -571,8 +571,6 @@ MSG_HASH(MENU_ENUM_LABEL_NETPLAY_CHECK_FRAMES,
       "netplay_check_frames")
 MSG_HASH(MENU_ENUM_LABEL_NETPLAY_CLIENT_SWAP_INPUT,
       "netplay_client_swap_input")
-MSG_HASH(MENU_ENUM_LABEL_NETPLAY_DELAY_FRAMES,
-      "netplay_delay_frames")
 MSG_HASH(MENU_ENUM_LABEL_NETPLAY_DISCONNECT,
       "menu_netplay_disconnect")
 MSG_HASH(MENU_ENUM_LABEL_NETPLAY_ENABLE,
@@ -597,6 +595,8 @@ MSG_HASH(MENU_ENUM_LABEL_NETPLAY_SPECTATE_PASSWORD,
       "netplay_spectate_password")
 MSG_HASH(MENU_ENUM_LABEL_NETPLAY_SPECTATOR_MODE_ENABLE,
       "netplay_spectator_mode_enable")
+MSG_HASH(MENU_ENUM_LABEL_NETPLAY_STATELESS_MODE,
+      "netplay_stateless_mode")
 MSG_HASH(MENU_ENUM_LABEL_NETPLAY_TCP_UDP_PORT,
       "netplay_tcp_udp_port")
 MSG_HASH(MENU_ENUM_LABEL_NETPLAY_LAN_SCAN_SETTINGS,

intl/msg_hash_us.c

@@ -1561,6 +1561,15 @@ int menu_hash_get_help_us_enum(enum msg_hash_enums msg, char *s, size_t len)
                "Increasing this value will increase \n"
                "performance, but introduce more latency.");
          break;
+      case MENU_ENUM_LABEL_NETPLAY_STATELESS_MODE:
+         snprintf(s, len,
+               "Whether to run netplay in a mode not requiring\n"
+               "save states. \n"
+               " \n"
+               "If set to true, a very fast network is required,\n"
+               "but no rewinding is performed, so there will be\n"
+               "no netplay jitter.\n");
+         break;
       case MENU_ENUM_LABEL_NETPLAY_CHECK_FRAMES:
          snprintf(s, len,
                "The frequency in frames with which netplay \n"

intl/msg_hash_us.h

@@ -976,6 +976,8 @@ MSG_HASH(MENU_ENUM_LABEL_VALUE_NETPLAY_PASSWORD,
       "Server Password")
 MSG_HASH(MENU_ENUM_LABEL_VALUE_NETPLAY_SETTINGS,
       "Netplay settings")
+MSG_HASH(MENU_ENUM_LABEL_VALUE_NETPLAY_STATELESS_MODE,
+      "Netplay Stateless Mode")
 MSG_HASH(MENU_ENUM_LABEL_VALUE_NETPLAY_SPECTATE_PASSWORD,
       "Server Spectate-Only Password")
 MSG_HASH(MENU_ENUM_LABEL_VALUE_NETPLAY_SPECTATOR_MODE_ENABLE,

menu/menu_displaylist.c

@@ -4698,7 +4698,7 @@ bool menu_displaylist_ctl(enum menu_displaylist_ctl_state type, void *data)
                   PARSE_ONLY_STRING, false) != -1)
                count++;
             if (menu_displaylist_parse_settings_enum(menu, info,
-                  MENU_ENUM_LABEL_NETPLAY_DELAY_FRAMES,
+                  MENU_ENUM_LABEL_NETPLAY_STATELESS_MODE,
                   PARSE_ONLY_UINT, false) != -1)
                count++;
             if (menu_displaylist_parse_settings_enum(menu, info,

menu/menu_setting.c

@@ -1721,16 +1721,9 @@ void general_write_handler(void *data)
          retroarch_override_setting_set(RARCH_OVERRIDE_SETTING_NETPLAY_MODE, NULL);
 #endif
          break;
-      case MENU_ENUM_LABEL_NETPLAY_DELAY_FRAMES:
+      case MENU_ENUM_LABEL_NETPLAY_STATELESS_MODE:
 #ifdef HAVE_NETWORKING
-         {
-            bool val = (settings->netplay.delay_frames > 0);
-
-            if (val)
-               retroarch_override_setting_set(RARCH_OVERRIDE_SETTING_NETPLAY_DELAY_FRAMES, NULL);
-            else
-               retroarch_override_setting_unset(RARCH_OVERRIDE_SETTING_NETPLAY_DELAY_FRAMES, NULL);
-         }
+         retroarch_override_setting_set(RARCH_OVERRIDE_SETTING_NETPLAY_STATELESS_MODE, NULL);
 #endif
          break;
       case MENU_ENUM_LABEL_NETPLAY_CHECK_FRAMES:
@@ -5605,19 +5598,20 @@ static bool setting_append_list(
                   general_read_handler);
             settings_data_list_current_add_flags(list, list_info, SD_FLAG_ALLOW_INPUT);
 
-            CONFIG_UINT(
+            CONFIG_BOOL(
                   list, list_info,
-                  &settings->netplay.delay_frames,
-                  MENU_ENUM_LABEL_NETPLAY_DELAY_FRAMES,
-                  MENU_ENUM_LABEL_VALUE_NETPLAY_DELAY_FRAMES,
-                  netplay_delay_frames,
+                  &settings->netplay.stateless_mode,
+                  MENU_ENUM_LABEL_NETPLAY_STATELESS_MODE,
+                  MENU_ENUM_LABEL_VALUE_NETPLAY_STATELESS_MODE,
+                  false,
+                  MENU_ENUM_LABEL_VALUE_OFF,
+                  MENU_ENUM_LABEL_VALUE_ON,
                   &group_info,
                   &subgroup_info,
                   parent_group,
                   general_write_handler,
-                  general_read_handler);
-            menu_settings_list_current_add_range(list, list_info, 0, 60, 1, true, false);
-            settings_data_list_current_add_flags(list, list_info, SD_FLAG_ADVANCED);
+                  general_read_handler,
+                  SD_FLAG_NONE);
 
             CONFIG_UINT(
                   list, list_info,

msg_hash.h

@@ -1008,6 +1008,7 @@ enum msg_hash_enums
    MENU_LABEL(BLUETOOTH_ENABLE),
    MENU_LABEL(NETPLAY_CLIENT_SWAP_INPUT),
    MENU_LABEL(NETPLAY_DELAY_FRAMES),
+   MENU_LABEL(NETPLAY_STATELESS_MODE),
    MENU_LABEL(NETPLAY_CHECK_FRAMES),
    MENU_LABEL(NETPLAY_SPECTATOR_MODE_ENABLE),
    MENU_LABEL(NETPLAY_TCP_UDP_PORT),

network/netplay/netplay_frontend.c

@@ -178,7 +178,7 @@ static bool netplay_poll(void)
 
    /* Read Netplay input, block if we're configured to stall for input every
     * frame */
-   if (netplay_data->delay_frames == 0 &&
+   if (netplay_data->stateless_mode &&
        netplay_data->unread_frame_count <= netplay_data->self_frame_count)
       res = netplay_poll_net_input(netplay_data, true);
    else
@@ -226,9 +226,9 @@ static bool netplay_poll(void)
          if (netplay_data->frame_run_time_avg)
             max_ahead = 50000 / netplay_data->frame_run_time_avg;
          else
-            max_ahead = netplay_data->delay_frames;
-         if (max_ahead > netplay_data->delay_frames)
-            max_ahead = netplay_data->delay_frames;
+            max_ahead = NETPLAY_MAX_STALL_FRAMES;
+         if (max_ahead > NETPLAY_MAX_STALL_FRAMES)
+            max_ahead = NETPLAY_MAX_STALL_FRAMES;
 
          /* Are we too far ahead? */
          netplay_update_unread_ptr(netplay_data);
@@ -846,7 +846,7 @@ bool init_netplay(void *direct_host, const char *server, unsigned port,
          netplay_is_client ? server : NULL,
          port ? port : RARCH_DEFAULT_PORT,
          play_password, spectate_password,
-         settings->netplay.delay_frames, settings->netplay.check_frames, &cbs,
+         settings->netplay.stateless_mode, settings->netplay.check_frames, &cbs,
          settings->netplay.nat_traversal, settings->username,
          quirks);
 

network/netplay/netplay_init.c

@@ -230,11 +230,11 @@ static bool init_socket(netplay_t *netplay, void *direct_host, const char *serve
 
 static bool netplay_init_socket_buffers(netplay_t *netplay)
 {
-   /* Make our packet buffer big enough for a save state and frames-many frames
-    * of input data, plus the headers for each of them */
+   /* Make our packet buffer big enough for a save state and stall-frames-many
+    * frames of input data, plus the headers for each of them */
    size_t i;
    size_t packet_buffer_size = netplay->zbuffer_size +
-      netplay->delay_frames * WORDS_PER_FRAME + (netplay->delay_frames+1)*3;
+      NETPLAY_MAX_STALL_FRAMES * WORDS_PER_FRAME + (NETPLAY_MAX_STALL_FRAMES+1)*3;
    netplay->packet_buffer_size = packet_buffer_size;
 
    for (i = 0; i < netplay->connections_size; i++)
@@ -366,18 +366,15 @@ bool netplay_wait_and_init_serialization(netplay_t *netplay)
    return false;
 }
 
-static bool netplay_init_buffers(netplay_t *netplay, unsigned frames)
+static bool netplay_init_buffers(netplay_t *netplay)
 {
    size_t packet_buffer_size;
 
    if (!netplay)
       return false;
 
-   /* * 2 + 1 because:
-    * Self sits in the middle,
-    * Other is allowed to drift as much as 'frames' frames behind
-    * Read is allowed to drift as much as 'frames' frames ahead */
-   netplay->buffer_size = frames * 2 + 1;
+   /* Enough to get ahead or behind by MAX_STALL_FRAMES frames */
+   netplay->buffer_size = NETPLAY_MAX_STALL_FRAMES + 1;
 
    netplay->buffer = (struct delta_frame*)calloc(netplay->buffer_size,
          sizeof(*netplay->buffer));
@@ -398,7 +395,7 @@ static bool netplay_init_buffers(netplay_t *netplay, unsigned frames)
  * @port                 : Port of server.
  * @play_password        : Password required to play.
  * @spectate_password    : Password required to connect.
- * @delay_frames         : Amount of delay frames.
+ * @stateless_mode       : Shall we use stateless mode?
  * @check_frames         : Frequency with which to check CRCs.
  * @cb                   : Libretro callbacks.
  * @nat_traversal        : If true, attempt NAT traversal.
@@ -412,7 +409,7 @@ static bool netplay_init_buffers(netplay_t *netplay, unsigned frames)
  */
 netplay_t *netplay_new(void *direct_host, const char *server, uint16_t port,
    const char *play_password, const char *spectate_password,
-   unsigned delay_frames, unsigned check_frames,
+   bool stateless_mode, unsigned check_frames,
    const struct retro_callbacks *cb, bool nat_traversal, const char *nick,
    uint64_t quirks)
 {
@@ -427,7 +424,7 @@ netplay_t *netplay_new(void *direct_host, const char *server, uint16_t port,
    netplay->player_max        = 1;
    netplay->is_server         = server == NULL;
    netplay->nat_traversal     = netplay->is_server ? nat_traversal : false;
-   netplay->delay_frames      = delay_frames;
+   netplay->stateless_mode    = stateless_mode;
    netplay->check_frames      = check_frames;
    netplay->crc_validity_checked = false;
    netplay->crcs_valid        = true;
@@ -458,7 +455,7 @@ netplay_t *netplay_new(void *direct_host, const char *server, uint16_t port,
       return NULL;
    }
 
-   if (!netplay_init_buffers(netplay, delay_frames))
+   if (!netplay_init_buffers(netplay))
    {
       free(netplay);
       return NULL;

network/netplay/netplay_private.h

@@ -45,7 +45,8 @@
 #define MAX_RETRIES                 16
 #define RETRY_MS                    500
 
-#define NETPLAY_FRAME_RUN_TIME_WINDOW 128
+#define NETPLAY_MAX_STALL_FRAMES       60
+#define NETPLAY_FRAME_RUN_TIME_WINDOW  120
 
 #define PREV_PTR(x) ((x) == 0 ? netplay->buffer_size - 1 : (x) - 1)
 #define NEXT_PTR(x) ((x + 1) % netplay->buffer_size)
@@ -178,22 +179,6 @@ enum netplay_cmd_mode_reasons
    NETPLAY_CMD_MODE_REFUSED_REASON_NO_SLOTS
 };
 
-/* These are the configurations sent by NETPLAY_CMD_CFG. */
-enum netplay_cmd_cfg
-{
-   /* Nickname */
-   NETPLAY_CFG_NICK           = 0x0001,
-
-   /* input.netplay_client_swap_input */
-   NETPLAY_CFG_SWAP_INPUT     = 0x0002,
-
-   /* netplay.delay_frames */
-   NETPLAY_CFG_DELAY_FRAMES   = 0x0004,
-
-   /* For more than 2 players */
-   NETPLAY_CFG_PLAYER_SLOT    = 0x0008
-};
-
 enum rarch_netplay_connection_mode
 {
    NETPLAY_CONNECTION_NONE = 0,
@@ -421,8 +406,8 @@ struct netplay
    bool local_paused;
    bool remote_paused;
 
-   /* Old-style stalling (to be removed) */
-   uint32_t delay_frames;
+   /* If true, never progress without peer input (stateless/rewindless mode) */
+   bool stateless_mode;
 
    /* We stall if we're far enough ahead that we couldn't transparently rewind.
     * To know if we could transparently rewind, we need to know how long
@@ -661,7 +646,7 @@ bool netplay_wait_and_init_serialization(netplay_t *netplay);
  * @port                 : Port of server.
  * @play_password        : Password required to play.
  * @spectate_password    : Password required to connect.
- * @delay_frames         : Amount of delay frames.
+ * @stateless_mode       : Shall we run in stateless mode?
  * @check_frames         : Frequency with which to check CRCs.
  * @cb                   : Libretro callbacks.
  * @nat_traversal        : If true, attempt NAT traversal.
@@ -675,7 +660,7 @@ bool netplay_wait_and_init_serialization(netplay_t *netplay);
  */
 netplay_t *netplay_new(void *direct_host, const char *server, uint16_t port,
    const char *play_password, const char *spectate_password,
-   unsigned delay_frames, unsigned check_frames,
+   bool stateless_mode, unsigned check_frames,
    const struct retro_callbacks *cb, bool nat_traversal, const char *nick,
    uint64_t quirks);
 

network/netplay/netplay_sync.c

@@ -15,6 +15,7 @@
  *  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <stdio.h>
 #include <stdlib.h>
 #include <sys/types.h>
 
@@ -203,7 +204,7 @@ bool netplay_sync_pre_frame(netplay_t *netplay)
          /* If the core can't serialize properly, we must stall for the
           * remote input on EVERY frame, because we can't recover */
          netplay->quirks |= NETPLAY_QUIRK_NO_SAVESTATES;
-         netplay->delay_frames = 0;
+         netplay->stateless_mode = true;
       }
 
       /* If we can't transmit savestates, we must stall until the client is ready */