From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from localhost (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id DF9002BB7D for ; Wed, 17 Apr 2019 15:56:41 -0400 (EDT) Received: from turing.freelists.org ([127.0.0.1]) by localhost (turing.freelists.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id O2t_ziBbmyai for ; Wed, 17 Apr 2019 15:56:41 -0400 (EDT) Received: from smtpng2.m.smailru.net (smtpng2.m.smailru.net [94.100.179.3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTPS id 771362B975 for ; Wed, 17 Apr 2019 15:56:41 -0400 (EDT) From: Vladislav Shpilevoy Subject: [tarantool-patches] [PATCH 4/4] swim: do not rebuild packet meta multiple times Date: Wed, 17 Apr 2019 22:56:37 +0300 Message-Id: <11325bc37ed084aac81f9bcdb8b8a041f43e08e4.1555530516.git.v.shpilevoy@tarantool.org> In-Reply-To: References: In-Reply-To: References: Sender: tarantool-patches-bounce@freelists.org Errors-to: tarantool-patches-bounce@freelists.org Reply-To: tarantool-patches@freelists.org List-Help: List-Unsubscribe: List-software: Ecartis version 1.0.0 List-Id: tarantool-patches List-Subscribe: List-Owner: List-post: List-Archive: To: tarantool-patches@freelists.org Cc: kostja@tarantool.org Before the patch there were 2 cases when an unchanged packet was rebuilt partially on each send: - cached round message's meta section was rebuilt on each EV_WRITE event in swim_scheduler_on_output() function; - broadcast message's meta section was rebuilt too even though its content does not depend on a broadcast interface. The third case appears with indirect pings patch which aggravates meta building business by routing and packet forwarding. When a packet needs to be forwarded farther, its meta is built in a special manner preserving the route before EV_WRITE appears, and on_output should not touch that meta. This patch adds a check preventing unnecessary meta rebuilds. Besides, the check and the meta building code are moved into a dedicated function out of swim_scheduler_on_output() - it allows to completely split logic of packing a message and sending it. Separated logic helps a lot when indirect pings are introduced. Part of #3234 --- src/lib/swim/swim_io.c | 29 ++++++++++++++++++++++++++--- 1 file changed, 26 insertions(+), 3 deletions(-) diff --git a/src/lib/swim/swim_io.c b/src/lib/swim/swim_io.c index 03d79ae3e..7d6addf02 100644 --- a/src/lib/swim/swim_io.c +++ b/src/lib/swim/swim_io.c @@ -57,6 +57,31 @@ swim_packet_create(struct swim_packet *packet) swim_packet_alloc_meta(packet, sizeof(struct swim_meta_header_bin)); } +/** Fill metadata prefix of a packet. */ +static inline void +swim_packet_build_meta(struct swim_packet *packet, + const struct sockaddr_in *src) +{ + char *meta = packet->meta; + char *end = packet->body; + /* + * Meta has already been built. It happens when the same + * task is resent multiple times. + */ + if (meta == end) + return; + struct swim_meta_header_bin header; + swim_meta_header_bin_create(&header, src); + assert(meta + sizeof(header) == end); + memcpy(meta, &header, sizeof(header)); + /* + * Once meta is built, it is consumed by the body. Used + * not to rebuild the meta again if the task will be + * scheduled again without changes in data. + */ + packet->body = packet->meta; +} + void swim_task_create(struct swim_task *task, swim_task_f complete, swim_task_f cancel, const char *desc) @@ -298,9 +323,7 @@ swim_scheduler_on_output(struct ev_loop *loop, struct ev_io *io, int events) say_verbose("SWIM %d: send %s to %s", swim_scheduler_fd(scheduler), task->desc, sio_strfaddr((struct sockaddr *) &task->dst, sizeof(task->dst))); - struct swim_meta_header_bin header; - swim_meta_header_bin_create(&header, &scheduler->transport.addr); - memcpy(task->packet.meta, &header, sizeof(header)); + swim_packet_build_meta(&task->packet, &scheduler->transport.addr); int rc = swim_transport_send(&scheduler->transport, task->packet.buf, task->packet.pos - task->packet.buf, (const struct sockaddr *) &task->dst, -- 2.17.2 (Apple Git-113)