From mboxrd@z Thu Jan 1 00:00:00 1970 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 5E2E8FA373D for ; Wed, 26 Oct 2022 07:20:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231476AbiJZHUT (ORCPT ); Wed, 26 Oct 2022 03:20:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38740 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230025AbiJZHUS (ORCPT ); Wed, 26 Oct 2022 03:20:18 -0400 Received: from out199-13.us.a.mail.aliyun.com (out199-13.us.a.mail.aliyun.com [47.90.199.13]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CF1AE303FF; Wed, 26 Oct 2022 00:20:15 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R171e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046059;MF=alibuda@linux.alibaba.com;NM=1;PH=DS;RN=8;SR=0;TI=SMTPD_---0VT69Lai_1666768810; Received: from 30.221.146.122(mailfrom:alibuda@linux.alibaba.com fp:SMTPD_---0VT69Lai_1666768810) by smtp.aliyun-inc.com; Wed, 26 Oct 2022 15:20:11 +0800 Message-ID: <8f938762-4060-10ed-32fd-ef7317b02300@linux.alibaba.com> Date: Wed, 26 Oct 2022 15:20:10 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.13.0 Subject: Re: [PATCH net-next v4 00/10] optimize the parallelism of SMC-R connections Content-Language: en-US To: Jan Karcher , kgraul@linux.ibm.com, wenjia@linux.ibm.com Cc: kuba@kernel.org, davem@davemloft.net, netdev@vger.kernel.org, linux-s390@vger.kernel.org, linux-rdma@vger.kernel.org References: <1666529042-40828-1-git-send-email-alibuda@linux.alibaba.com> <95feb2a1-d17a-6233-d3d0-eaebf26d2284@linux.ibm.com> From: "D. Wythe" In-Reply-To: <95feb2a1-d17a-6233-d3d0-eaebf26d2284@linux.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org Thank you for your information. I'm trying to debug it. we will let you know as soon as possible. Best Wishes. D. Wythe On 10/24/22 9:11 PM, Jan Karcher wrote: > Hi D. Wythe, > > I re-run the tests with your fix. > SMC-R works fine now. For SMC-D we still have the following problem. It is kind of the same as i reported in v2 but even weirder: > > smc stats: > > t8345011 > SMC-D Connections Summary >   Total connections handled          2465 > SMC-R Connections Summary >   Total connections handled           232 > > t8345010 > SMC-D Connections Summary >   Total connections handled          2290 > SMC-R Connections Summary >   Total connections handled           231 > > > smc linkgroups: > > t8345011 > [root@t8345011 ~]# smcr linkgroup > LG-ID    LG-Role  LG-Type  VLAN  #Conns  PNET-ID > 00000400 SERV     SYM         0       0  NET25 > [root@t8345011 ~]# smcd linkgroup > LG-ID    VLAN  #Conns  PNET-ID > 00000300    0      16  NET25 > > t8345010 > [root@t8345010 tela-kernel]# smcr linkgroup > LG-ID    LG-Role  LG-Type  VLAN  #Conns  PNET-ID > 00000400 CLNT     SYM         0       0  NET25 > [root@t8345010 tela-kernel]# smcd linkgroup > LG-ID    VLAN  #Conns  PNET-ID > 00000300    0       1  NET25 > > > smcss: > > t8345011 > [root@t8345011 ~]# smcss > State          UID   Inode   Local Address           Peer Address     Intf Mode > > t8345010 > [root@t8345010 tela-kernel]# smcss > State          UID   Inode   Local Address           Peer Address     Intf Mode > > > lsmod: > > t8345011 > [root@t8345011 ~]# lsmod | grep smc > smc                   225280  18 ism,smc_diag > t8345010 > [root@t8345010 tela-kernel]# lsmod | grep smc > smc                   225280  3 ism,smc_diag > > Also smc_dbg and netstat do not show any more information on this problem. We only see in the dmesg that the code seems to build up SMC-R linkgroups even tho we are running the SMC-D tests. > NOTE: we disabled the syncookies for the tests. > > dmesg: > > t8345011 > smc-tests: test_smcapp_torture_test started > kernel: TCP: request_sock_TCP: Possible SYN flooding on port 22465. Dropping request.  Check SNMP counters. > kernel: smc: SMC-R lg 00000400 net 1 link added: id 00000401, peerid 00000401, ibdev mlx5_0, ibport 1 > kernel: smc: SMC-R lg 00000400 net 1 state changed: SINGLE, pnetid NET25 > kernel: smc: SMC-R lg 00000400 net 1 link added: id 00000402, peerid 00000402, ibdev mlx5_1, ibport 1 > kernel: smc: SMC-R lg 00000400 net 1 state changed: SYMMETRIC, pnetid NET25 > > t8345010 > smc-tests: test_smcapp_torture_test started > kernel: smc: SMC-R lg 00000400 net 1 link added: id 00000401, peerid 00000401, ibdev mlx5_0, ibport 1 > kernel: smc: SMC-R lg 00000400 net 1 state changed: SINGLE, pnetid NET25 > kernel: smc: SMC-R lg 00000400 net 1 link added: id 00000402, peerid 00000402, ibdev mlx5_1, ibport 1 > kernel: smc: SMC-R lg 00000400 net 1 state changed: SYMMETRIC, pnetid NET25 > > If this output does not help and if you want us to look deeper into it feel free to let us know and we can debug further. > > On 23/10/2022 14:43, D.Wythe wrote: >> From: "D.Wythe" >> >> This patch set attempts to optimize the parallelism of SMC-R connections, >> mainly to reduce unnecessary blocking on locks, and to fix exceptions that >> occur after thoses optimization. >> >> According to Off-CPU graph, SMC worker's off-CPU as that: >> >> smc_close_passive_work                  (1.09%) >>          smcr_buf_unuse                  (1.08%) >>                  smc_llc_flow_initiate   (1.02%) >> >> smc_listen_work                         (48.17%) >>          __mutex_lock.isra.11            (47.96%) >> >> >> An ideal SMC-R connection process should only block on the IO events >> of the network, but it's quite clear that the SMC-R connection now is >> queued on the lock most of the time. >> >> The goal of this patchset is to achieve our ideal situation where >> network IO events are blocked for the majority of the connection lifetime. >> >> There are three big locks here: >> >> 1. smc_client_lgr_pending & smc_server_lgr_pending >> >> 2. llc_conf_mutex >> >> 3. rmbs_lock & sndbufs_lock >> >> And an implementation issue: >> >> 1. confirm/delete rkey msg can't be sent concurrently while >> protocol allows indeed. >> >> Unfortunately,The above problems together affect the parallelism of >> SMC-R connection. If any of them are not solved. our goal cannot >> be achieved. >> >> After this patch set, we can get a quite ideal off-CPU graph as >> following: >> >> smc_close_passive_work                                  (41.58%) >>          smcr_buf_unuse                                  (41.57%) >>                  smc_llc_do_delete_rkey                  (41.57%) >> >> smc_listen_work                                         (39.10%) >>          smc_clc_wait_msg                                (13.18%) >>                  tcp_recvmsg_locked                      (13.18) >>          smc_listen_find_device                          (25.87%) >>                  smcr_lgr_reg_rmbs                       (25.87%) >>                          smc_llc_do_confirm_rkey         (25.87%) >> >> We can see that most of the waiting times are waiting for network IO >> events. This also has a certain performance improvement on our >> short-lived conenction wrk/nginx benchmark test: >> >> +--------------+------+------+-------+--------+------+--------+ >> |conns/qps     |c4    | c8   |  c16  |  c32   | c64  |  c200  | >> +--------------+------+------+-------+--------+------+--------+ >> |SMC-R before  |9.7k  | 10k  |  10k  |  9.9k  | 9.1k |  8.9k  | >> +--------------+------+------+-------+--------+------+--------+ >> |SMC-R now     |13k   | 19k  |  18k  |  16k   | 15k  |  12k   | >> +--------------+------+------+-------+--------+------+--------+ >> |TCP           |15k   | 35k  |  51k  |  80k   | 100k |  162k  | >> +--------------+------+------+-------+--------+------+--------+ >> >> The reason why the benefit is not obvious after the number of connections >> has increased dues to workqueue. If we try to change workqueue to UNBOUND, >> we can obtain at least 4-5 times performance improvement, reach up to half >> of TCP. However, this is not an elegant solution, the optimization of it >> will be much more complicated. But in any case, we will submit relevant >> optimization patches as soon as possible. >> >> Please note that the premise here is that the lock related problem >> must be solved first, otherwise, no matter how we optimize the workqueue, >> there won't be much improvement. >> >> Because there are a lot of related changes to the code, if you have >> any questions or suggestions, please let me know. >> >> Thanks >> D. Wythe >> >> v1 -> v2: >> >> 1. Fix panic in SMC-D scenario >> 2. Fix lnkc related hashfn calculation exception, caused by operator >> priority >> 3. Only wake up one connection if the lnk is not active >> 4. Delete obsolete unlock logic in smc_listen_work() >> 5. PATCH format, do Reverse Christmas tree >> 6. PATCH format, change all xxx_lnk_xxx function to xxx_link_xxx >> 7. PATCH format, add correct fix tag for the patches for fixes. >> 8. PATCH format, fix some spelling error >> 9. PATCH format, rename slow to do_slow >> >> v2 -> v3: >> >> 1. add SMC-D support, remove the concept of link cluster since SMC-D has >> no link at all. Replace it by lgr decision maker, who provides suggestions >> to SMC-D and SMC-R on whether to create new link group. >> >> 2. Fix the corruption problem described by PATCH 'fix application >> data exception' on SMC-D. >> >> v3 -> v4: >> >> 1. Fix panic caused by uninitialization map. >> >> D. Wythe (10): >>    net/smc: remove locks smc_client_lgr_pending and >>      smc_server_lgr_pending >>    net/smc: fix SMC_CLC_DECL_ERR_REGRMB without smc_server_lgr_pending >>    net/smc: allow confirm/delete rkey response deliver multiplex >>    net/smc: make SMC_LLC_FLOW_RKEY run concurrently >>    net/smc: llc_conf_mutex refactor, replace it with rw_semaphore >>    net/smc: use read semaphores to reduce unnecessary blocking in >>      smc_buf_create() & smcr_buf_unuse() >>    net/smc: reduce unnecessary blocking in smcr_lgr_reg_rmbs() >>    net/smc: replace mutex rmbs_lock and sndbufs_lock with rw_semaphore >>    net/smc: Fix potential panic dues to unprotected >>      smc_llc_srv_add_link() >>    net/smc: fix application data exception >> >>   net/smc/af_smc.c   |  70 ++++---- >>   net/smc/smc_core.c | 478 +++++++++++++++++++++++++++++++++++++++++++++++------ >>   net/smc/smc_core.h |  36 +++- >>   net/smc/smc_llc.c  | 277 ++++++++++++++++++++++--------- >>   net/smc/smc_llc.h  |   6 + >>   net/smc/smc_wr.c   |  10 -- >>   net/smc/smc_wr.h   |  10 ++ >>   7 files changed, 712 insertions(+), 175 deletions(-) >>