From patchwork Tue Jan 4 10:58:50 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "D. Wythe" X-Patchwork-Id: 12703344 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 60561C433EF for ; Tue, 4 Jan 2022 10:59:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231768AbiADK7C (ORCPT ); Tue, 4 Jan 2022 05:59:02 -0500 Received: from out30-42.freemail.mail.aliyun.com ([115.124.30.42]:57592 "EHLO out30-42.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231776AbiADK7C (ORCPT ); Tue, 4 Jan 2022 05:59:02 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R121e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04395;MF=alibuda@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0V0vAWLj_1641293939; Received: from localhost(mailfrom:alibuda@linux.alibaba.com fp:SMTPD_---0V0vAWLj_1641293939) by smtp.aliyun-inc.com(127.0.0.1); Tue, 04 Jan 2022 18:58:59 +0800 From: "D. Wythe" To: kgraul@linux.ibm.com Cc: kuba@kernel.org, davem@davemloft.net, netdev@vger.kernel.org, linux-s390@vger.kernel.org, linux-rdma@vger.kernel.org, "D. Wythe" Subject: [PATCH net-next] net/smc: Reduce overflow of smc clcsock listen queue Date: Tue, 4 Jan 2022 18:58:50 +0800 Message-Id: <1641293930-110897-1-git-send-email-alibuda@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org From: "D. Wythe" In nginx/wrk multithread and 10K connections benchmark, the backend TCP connection established very slowly, and lots of TCP connections stay in SYN_SENT state. Server: smc_run nginx Client: smc_run wrk -c 10000 -t 4 http://server Socket state in client host (wrk) shows like: ss -t | wc -l 10000 ss -t | grep "SYN-SENT" | wc -l 6248 While the socket state in server host (nginx) shows like: ss -t | wc -l 3752 Furthermore, the netstate of server host shows like: 145042 times the listen queue of a socket overflowed 145042 SYNs to LISTEN sockets dropped This issue caused by smc_listen_work(), since the smc_tcp_listen_work() shared the same workqueue (smc_hs_wq) with smc_listen_work(), while smc_listen_work() do blocking wait for smc connection established, which meanwhile block the accept() from TCP listen queue. This patch create a independent workqueue(smc_tcp_ls_wq) for smc_tcp_listen_work(), separate it from smc_listen_work(), which is quite acceptable considering that smc_tcp_listen_work() runs very fast. After this patch, the smc 10K connections benchmark in my case is 5 times faster than before. Before patch : smc_run ./wrk -c 10000 -t 3 -d 20 http://server 3 threads and 10000 connections 143300 requests in 20.04s, 94.29MB read Requests/sec: 7150.33 Transfer/sec: 4.70MB After patch: smc_run ./wrk -c 10000 -t 3 -d 20 http://server 3 threads and 10000 connections 902091 requests in 21.99s, 593.56MB read Requests/sec: 41017.52 Transfer/sec: 26.99MB Signed-off-by: D. Wythe Reviewed-by: Tony Lu --- net/smc/af_smc.c | 13 +++++++++++-- net/smc/smc.h | 1 + 2 files changed, 12 insertions(+), 2 deletions(-) diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c index 0bb614e..4d0bc0d 100644 --- a/net/smc/af_smc.c +++ b/net/smc/af_smc.c @@ -62,6 +62,7 @@ * creation on client */ +struct workqueue_struct *smc_tcp_ls_wq; /* wq for tcp listen work*/ struct workqueue_struct *smc_hs_wq; /* wq for handshake work */ struct workqueue_struct *smc_close_wq; /* wq for close work */ @@ -1872,7 +1873,7 @@ static void smc_clcsock_data_ready(struct sock *listen_clcsock) lsmc->clcsk_data_ready(listen_clcsock); if (lsmc->sk.sk_state == SMC_LISTEN) { sock_hold(&lsmc->sk); /* sock_put in smc_tcp_listen_work() */ - if (!queue_work(smc_hs_wq, &lsmc->tcp_listen_work)) + if (!queue_work(smc_tcp_ls_wq, &lsmc->tcp_listen_work)) sock_put(&lsmc->sk); } } @@ -2610,9 +2611,14 @@ static int __init smc_init(void) goto out_nl; rc = -ENOMEM; + + smc_tcp_ls_wq = alloc_workqueue("smc_tcp_ls_wq", 0, 0); + if (!smc_tcp_ls_wq) + goto out_pnet; + smc_hs_wq = alloc_workqueue("smc_hs_wq", 0, 0); if (!smc_hs_wq) - goto out_pnet; + goto out_alloc_tcp_ls_wq; smc_close_wq = alloc_workqueue("smc_close_wq", 0, 0); if (!smc_close_wq) @@ -2709,6 +2715,8 @@ static int __init smc_init(void) destroy_workqueue(smc_close_wq); out_alloc_hs_wq: destroy_workqueue(smc_hs_wq); +out_alloc_tcp_ls_wq: + destroy_workqueue(smc_tcp_ls_wq); out_pnet: smc_pnet_exit(); out_nl: @@ -2728,6 +2736,7 @@ static void __exit smc_exit(void) smc_core_exit(); smc_ib_unregister_client(); destroy_workqueue(smc_close_wq); + destroy_workqueue(smc_tcp_ls_wq); destroy_workqueue(smc_hs_wq); proto_unregister(&smc_proto6); proto_unregister(&smc_proto); diff --git a/net/smc/smc.h b/net/smc/smc.h index b1d6625..f3bb4be 100644 --- a/net/smc/smc.h +++ b/net/smc/smc.h @@ -256,6 +256,7 @@ static inline struct smc_sock *smc_sk(const struct sock *sk) return (struct smc_sock *)sk; } +extern struct workqueue_struct *smc_tcp_ls_wq; /* wq for tcp listen work*/ extern struct workqueue_struct *smc_hs_wq; /* wq for handshake work */ extern struct workqueue_struct *smc_close_wq; /* wq for close work */