From 9c7c57cae8e6f0553ed834e0188090288b70fa21 Mon Sep 17 00:00:00 2001 From: Andrew Clayton Date: Wed, 14 Aug 2024 00:33:13 +0100 Subject: [PATCH] conf, router: Make the listen(2) backlog configurable @oopsoop2 on GitHub reported a performance issue related to the default listen(2) backlog size of 511 on nginx. They found that increasing it helped, nginx has a config option to configure this. They would like to be able to do the same on Unit (which also defaults to 511 on some systems). This seems reasonable. NOTE: On Linux before commit 97c15fa38 ("socket: Use a default listen backlog of -1 on Linux") we defaulted to 511. Since that commit we default to the Kernels default, which before 5.4 is 128 and after is 4096. This adds a new per-listener 'backlog' config option, e.g { "listeners": { "[::1]:8080": { "pass": "routes", "backlog": 1024 }, } ... } This doesn't effect the control socket. Closes: https://github.com/nginx/unit/issues/1384 Reported-by: Signed-off-by: Andrew Clayton --- src/nxt_conf_validation.c | 32 ++++++++++++++++++++++++++++++++ src/nxt_router.c | 27 ++++++++++++++++++--------- 2 files changed, 50 insertions(+), 9 deletions(-) diff --git a/src/nxt_conf_validation.c b/src/nxt_conf_validation.c index 04091745c..80eb55cb9 100644 --- a/src/nxt_conf_validation.c +++ b/src/nxt_conf_validation.c @@ -176,6 +176,8 @@ static nxt_int_t nxt_conf_vldt_app_name(nxt_conf_validation_t *vldt, nxt_conf_value_t *value, void *data); static nxt_int_t nxt_conf_vldt_forwarded(nxt_conf_validation_t *vldt, nxt_conf_value_t *value, void *data); +static nxt_int_t nxt_conf_vldt_listen_backlog(nxt_conf_validation_t *vldt, + nxt_conf_value_t *value, void *data); static nxt_int_t nxt_conf_vldt_app(nxt_conf_validation_t *vldt, nxt_str_t *name, nxt_conf_value_t *value); static nxt_int_t nxt_conf_vldt_object(nxt_conf_validation_t *vldt, @@ -424,6 +426,10 @@ static nxt_conf_vldt_object_t nxt_conf_vldt_listener_members[] = { .type = NXT_CONF_VLDT_OBJECT, .validator = nxt_conf_vldt_object, .u.members = nxt_conf_vldt_client_ip_members + }, { + .name = nxt_string("backlog"), + .type = NXT_CONF_VLDT_NUMBER, + .validator = nxt_conf_vldt_listen_backlog, }, #if (NXT_TLS) @@ -2677,6 +2683,32 @@ nxt_conf_vldt_forwarded(nxt_conf_validation_t *vldt, nxt_conf_value_t *value, } +static nxt_int_t +nxt_conf_vldt_listen_backlog(nxt_conf_validation_t *vldt, + nxt_conf_value_t *value, void *data) +{ + int64_t backlog; + + backlog = nxt_conf_get_number(value); + + /* + * POSIX allows this to be 0 and some systems use -1 to + * indicate to use the OS's default value. + */ + if (backlog < -1) { + return nxt_conf_vldt_error(vldt, "The \"backlog\" number must be " + "equal to or greater than -1."); + } + + if (backlog > NXT_INT32_T_MAX) { + return nxt_conf_vldt_error(vldt, "The \"backlog\" number must " + "not exceed %d.", NXT_INT32_T_MAX); + } + + return NXT_OK; +} + + static nxt_int_t nxt_conf_vldt_app(nxt_conf_validation_t *vldt, nxt_str_t *name, nxt_conf_value_t *value) diff --git a/src/nxt_router.c b/src/nxt_router.c index 432094511..96b55e31e 100644 --- a/src/nxt_router.c +++ b/src/nxt_router.c @@ -40,6 +40,7 @@ typedef struct { typedef struct { nxt_str_t pass; nxt_str_t application; + int backlog; } nxt_router_listener_conf_t; @@ -166,7 +167,7 @@ static void nxt_router_app_prefork_ready(nxt_task_t *task, static void nxt_router_app_prefork_error(nxt_task_t *task, nxt_port_recv_msg_t *msg, void *data); static nxt_socket_conf_t *nxt_router_socket_conf(nxt_task_t *task, - nxt_router_temp_conf_t *tmcf, nxt_str_t *name); + nxt_router_temp_conf_t *tmcf, nxt_str_t *name, int backlog); static nxt_int_t nxt_router_listen_socket_find(nxt_router_temp_conf_t *tmcf, nxt_socket_conf_t *nskcf, nxt_sockaddr_t *sa); @@ -1494,6 +1495,12 @@ static nxt_conf_map_t nxt_router_listener_conf[] = { NXT_CONF_MAP_STR_COPY, offsetof(nxt_router_listener_conf_t, application), }, + + { + nxt_string("backlog"), + NXT_CONF_MAP_INT32, + offsetof(nxt_router_listener_conf_t, backlog), + }, }; @@ -1964,13 +1971,10 @@ nxt_router_conf_create(nxt_task_t *task, nxt_router_temp_conf_t *tmcf, break; } - skcf = nxt_router_socket_conf(task, tmcf, &name); - if (skcf == NULL) { - goto fail; - } - nxt_memzero(&lscf, sizeof(lscf)); + lscf.backlog = -1; + ret = nxt_conf_map_object(mp, listener, nxt_router_listener_conf, nxt_nitems(nxt_router_listener_conf), &lscf); @@ -1981,6 +1985,11 @@ nxt_router_conf_create(nxt_task_t *task, nxt_router_temp_conf_t *tmcf, nxt_debug(task, "application: %V", &lscf.application); + skcf = nxt_router_socket_conf(task, tmcf, &name, lscf.backlog); + if (skcf == NULL) { + goto fail; + } + // STUB, default values if http block is not defined. skcf->header_buffer_size = 2048; skcf->large_header_buffer_size = 8192; @@ -2684,7 +2693,7 @@ nxt_router_application_init(nxt_router_conf_t *rtcf, nxt_str_t *name, static nxt_socket_conf_t * nxt_router_socket_conf(nxt_task_t *task, nxt_router_temp_conf_t *tmcf, - nxt_str_t *name) + nxt_str_t *name, int backlog) { size_t size; nxt_int_t ret; @@ -2728,7 +2737,7 @@ nxt_router_socket_conf(nxt_task_t *task, nxt_router_temp_conf_t *tmcf, nxt_listen_socket_remote_size(ls); ls->socket = -1; - ls->backlog = NXT_LISTEN_BACKLOG; + ls->backlog = backlog > -1 ? backlog : NXT_LISTEN_BACKLOG; ls->flags = NXT_NONBLOCK; ls->read_after_accept = 1; } @@ -2875,7 +2884,7 @@ nxt_router_listen_socket_ready(nxt_task_t *task, nxt_port_recv_msg_t *msg, nxt_socket_defer_accept(task, s, rpc->socket_conf->listen->sockaddr); - ret = nxt_listen_socket(task, s, NXT_LISTEN_BACKLOG); + ret = nxt_listen_socket(task, s, rpc->socket_conf->listen->backlog); if (nxt_slow_path(ret != NXT_OK)) { goto fail; }