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 X-Spam-Level: X-Spam-Status: No, score=-8.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B8D3AC433B4 for ; Sun, 25 Apr 2021 09:52:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 933AE6128B for ; Sun, 25 Apr 2021 09:52:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229898AbhDYJxJ (ORCPT ); Sun, 25 Apr 2021 05:53:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38730 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229551AbhDYJxI (ORCPT ); Sun, 25 Apr 2021 05:53:08 -0400 Received: from mail-qt1-x82e.google.com (mail-qt1-x82e.google.com [IPv6:2607:f8b0:4864:20::82e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 14F26C061574 for ; Sun, 25 Apr 2021 02:52:28 -0700 (PDT) Received: by mail-qt1-x82e.google.com with SMTP id c6so39608912qtc.1 for ; Sun, 25 Apr 2021 02:52:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=reduxio-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=LMBNtwNdsegOtzvgkIzFGnumPYe/dlYwir60acgKtks=; b=YjXwzamewNotcANQRvKL9mpcMFEj8be8D4TCKP5zVpo7eHxcVMdhLAwGQuJka4AkVx Qki20NyT3LcD8wHbjIXWlp4ir4q8iHy+tn/uIkh/eBpdsEMhPpFVun5+Zv7ZW4KCoOeB VfXGSt8NYB5Eh7CV3ya7v8jApeYNCxrVnJN61wRwePIcF/NnQtVjOQmgaBl/TcpXiszL D13dLh+pe/Gyf5DyhYNh6jIXOKy4bPne1DIDGXXTUvXYHKNa+Vuf+gsRr89q8tszMK2Y Pkfdz8fZ2pqJ6ohM4cZW2AZEOVjah9jBmEERJDq1YcW/+vUlBlSI+p/F/Nt9z76mUzuB ECFQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=LMBNtwNdsegOtzvgkIzFGnumPYe/dlYwir60acgKtks=; b=AQxpChtFrON77YB12DTmPhLgLkQnhpNxJMmbRjffw1GjXl5UzKkBKiE3KrQGN4jtQ0 fRUxkkPkLiG93W/UPO7gqCeeH0KVbh6S7YWU2/gE8DJ7y7txR89SU2L5EwqbogHGjRJ0 6Ri6A3AP3u0512Bxvzpf7g+rRQ4+qYeOuQ9fv+M+a/HqasnZYMtQOtrd+4sbdmfyXsAP zPmTuTM5Y83SxaXNs7qpjb2A1L4EaDPw6SBBKdzRmTxwwPLyLn7A6Arw2Azy1oJyqznw 6SdMUDHnZyXwalEOdxVPAEcfZfqGmZhFFYYOkzswxgaNjsBGnT8W1qLGzKJ5F1iqJ8Eu KKMw== X-Gm-Message-State: AOAM532wG6FX+b8t7l8SqeLQzSmd4yWld2Idsff85W1m+YUSIP9cAUgT kiFNYXet75TCM4WnDSH/v3dZ8htLbOFJudqd7Y+9zQ== X-Google-Smtp-Source: ABdhPJxJzVfrp+lMi+b8jRupdu/TpZz1C8tRB+pxriFxxprlqsd+FSQpHwfP4yBuygB3juYO7Hre1xWpSjO4SrQ3Hos= X-Received: by 2002:a05:622a:6:: with SMTP id x6mr11641433qtw.1.1619344347259; Sun, 25 Apr 2021 02:52:27 -0700 (PDT) MIME-Version: 1.0 References: <6d9d2610-e7c0-ad29-fd30-85da8222ab83@gmail.com> In-Reply-To: From: Michael Stoler Date: Sun, 25 Apr 2021 12:52:16 +0300 Message-ID: Subject: Re: io_uring networking performance degradation To: Pavel Begunkov Cc: io-uring@vger.kernel.org, Jens Axboe Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org Because of unstable working of perf over AWS VM I recheck test on physical machine: Ubuntu 20.04, 5.8.0-50-generic kernel, CPU AMD EPYC 7272 12-Core Processor 3200MHz, BogoMIPS 5789.39, NIC melanox 5, Speed: 25000Mb/s Full Duplex. Over physical machine performance degradation is much less pronounced but still exists: io_uring-echo-server Speed: 143081 request/sec, 143081 response/sec epoll-echo-server Speed: 150692 request/sec, 150692 response/sec epoll-echo-server is 5% faster "perf top" with io_uring-echo-server: PerfTop: 16481 irqs/sec kernel:98.5% exact: 99.8% lost: 0/0 drop: 0/0 [4000Hz cycles], (all, 24 CPUs) ------------------------------------------------------------------------------- 8.66% [kernel] [k] __x86_indirect_thunk_rax 8.49% [kernel] [k] copy_user_generic_string 5.57% [kernel] [k] memset 2.81% [kernel] [k] tcp_rate_skb_sent 2.32% [kernel] [k] __alloc_skb 2.16% [kernel] [k] __check_object_size 1.44% [unknown] [k] 0xffffffffc100c296 1.28% [kernel] [k] tcp_write_xmit 1.22% [kernel] [k] iommu_dma_map_page 1.16% [kernel] [k] kmem_cache_free 1.14% [kernel] [k] __softirqentry_text_start 1.06% [unknown] [k] 0xffffffffc1008a7e 1.03% [kernel] [k] __skb_datagram_iter 0.97% [kernel] [k] __dev_queue_xmit 0.86% [kernel] [k] ipv4_mtu 0.85% [kernel] [k] tcp_schedule_loss_probe 0.80% [kernel] [k] tcp_release_cb 0.78% [unknown] [k] 0xffffffffc100c290 0.77% [unknown] [k] 0xffffffffc100c295 0.76% perf [.] __symbols__insert "perf top" with epoll-echo-server: PerfTop: 24255 irqs/sec kernel:98.3% exact: 99.6% lost: 0/0 drop: 0/0 [4000Hz cycles], (all, 24 CPUs) ------------------------------------------------------------------------------- 8.77% [kernel] [k] __x86_indirect_thunk_rax 7.50% [kernel] [k] copy_user_generic_string 4.10% [kernel] [k] memset 2.70% [kernel] [k] tcp_rate_skb_sent 2.18% [kernel] [k] __check_object_size 2.09% [kernel] [k] __alloc_skb 1.61% [unknown] [k] 0xffffffffc100c296 1.47% [kernel] [k] __virt_addr_valid 1.40% [kernel] [k] iommu_dma_map_page 1.37% [unknown] [k] 0xffffffffc1008a7e 1.22% [kernel] [k] tcp_poll 1.16% [kernel] [k] __softirqentry_text_start 1.15% [kernel] [k] tcp_stream_memory_free 1.07% [kernel] [k] tcp_write_xmit 1.06% [kernel] [k] kmem_cache_free 1.03% [kernel] [k] tcp_release_cb 0.96% [kernel] [k] syscall_return_via_sysret 0.90% [kernel] [k] __lock_text_start 0.82% [kernel] [k] __copy_skb_header 0.81% [kernel] [k] amd_iommu_map Regards Michael Stoler On Tue, Apr 20, 2021 at 1:44 PM Michael Stoler wrote: > > Hi, perf data and tops for linux-5.8 are here: > http://rdxdownloads.rdxdyn.com/michael_stoler_perf_data.tgz > > Regards > Michael Stoler > > On Mon, Apr 19, 2021 at 5:27 PM Michael Stoler wrote: > > > > 1) linux-5.12-rc8 shows generally same picture: > > > > average load, 70-85% CPU core usage, 128 bytes packets > > echo_bench --address '172.22.150.170:7777' --number 10 --duration > > 60 --length 128` > > epoll-echo-server: Speed: 71513 request/sec, 71513 response/sec > > io_uring_echo_server: Speed: 64091 request/sec, 64091 response/sec > > epoll-echo-server is 11% faster > > > > high load, 95-100% CPU core usage, 128 bytes packets > > echo_bench --address '172.22.150.170:7777' --number 20 --duration > > 60 --length 128` > > epoll-echo-server: Speed: 130186 request/sec, 130186 response/sec > > io_uring_echo_server: Speed: 109793 request/sec, 109793 response/sec > > epoll-echo-server is 18% faster > > > > average load, 70-85% CPU core usage, 2048 bytes packets > > echo_bench --address '172.22.150.170:7777' --number 10 --duration > > 60 --length 2048` > > epoll-echo-server: Speed: 63082 request/sec, 63082 response/sec > > io_uring_echo_server: Speed: 59449 request/sec, 59449 response/sec > > epoll-echo-server is 6% faster > > > > high load, 95-100% CPU core usage, 2048 bytes packets > > echo_bench --address '172.22.150.170:7777' --number 20 --duration > > 60 --length 2048` > > epoll-echo-server: Speed: 110402 request/sec, 110402 response/sec > > io_uring_echo_server: Speed: 88718 request/sec, 88718 response/sec > > epoll-echo-server is 24% faster > > > > > > 2-3) The "perf top" doesn't work stable with Ubuntu over AWS. All the > > time it shows errors: "Uhhuh. NMI received for unknown reason", "Do > > you have a strange power saving mode enabled?", "Dazed and confused, > > but trying to continue". > > > > Regards > > Michael Stoler > > > > On Mon, Apr 19, 2021 at 1:20 PM Pavel Begunkov wrote: > > > > > > On 4/19/21 10:13 AM, Michael Stoler wrote: > > > > We are trying to reproduce reported on page > > > > https://github.com/frevib/io_uring-echo-server/blob/master/benchmarks/benchmarks.md > > > > results with a more realistic environment: > > > > 1. Internode networking in AWS cluster with i3.16xlarge nodes type(25 > > > > Gigabit network connection between client and server) > > > > 2. 128 and 2048 packet sizes, to simulate typical payloads > > > > 3. 10 clients to get 75-95% CPU utilization by server to simulate > > > > server's normal load > > > > 4. 20 clients to get 100% CPU utilization by server to simulate > > > > server's hard load > > > > > > > > Software: > > > > 1. OS: Ubuntu 20.04.2 LTS HWE with 5.8.0-45-generic kernel with latest liburing > > > > 2. io_uring-echo-server: https://github.com/frevib/io_uring-echo-server > > > > 3. epoll-echo-server: https://github.com/frevib/epoll-echo-server > > > > 4. benchmark: https://github.com/haraldh/rust_echo_bench > > > > 5. all commands runs with "hwloc-bind os=eth1" > > > > > > > > The results are confusing, epoll_echo_server shows stable advantage > > > > over io_uring-echo-server, despite reported advantage of > > > > io_uring-echo-server: > > > > > > > > 128 bytes packet size, 10 clients, 75-95% CPU core utilization by server: > > > > echo_bench --address '172.22.117.67:7777' -c 10 -t 60 -l 128 > > > > epoll_echo_server: Speed: 80999 request/sec, 80999 response/sec > > > > io_uring_echo_server: Speed: 74488 request/sec, 74488 response/sec > > > > epoll_echo_server is 8% faster > > > > > > > > 128 bytes packet size, 20 clients, 100% CPU core utilization by server: > > > > echo_bench --address '172.22.117.67:7777' -c 20 -t 60 -l 128 > > > > epoll_echo_server: Speed: 129063 request/sec, 129063 response/sec > > > > io_uring_echo_server: Speed: 102681 request/sec, 102681 response/sec > > > > epoll_echo_server is 25% faster > > > > > > > > 2048 bytes packet size, 10 clients, 75-95% CPU core utilization by server: > > > > echo_bench --address '172.22.117.67:7777' -c 10 -t 60 -l 2048 > > > > epoll_echo_server: Speed: 74421 request/sec, 74421 response/sec > > > > io_uring_echo_server: Speed: 66510 request/sec, 66510 response/sec > > > > epoll_echo_server is 11% faster > > > > > > > > 2048 bytes packet size, 20 clients, 100% CPU core utilization by server: > > > > echo_bench --address '172.22.117.67:7777' -c 20 -t 60 -l 2048 > > > > epoll_echo_server: Speed: 108704 request/sec, 108704 response/sec > > > > io_uring_echo_server: Speed: 85536 request/sec, 85536 response/sec > > > > epoll_echo_server is 27% faster > > > > > > > > Why io_uring shows consistent performance degradation? What is going wrong? > > > > > > 5.8 is pretty old, and I'm not sure all the performance problems were > > > addressed there. Apart from missing common optimisations as you may > > > have seen in the thread, it looks to me it doesn't have sighd(?) lock > > > hammering fix. Jens, knows better it has been backported or not. > > > > > > So, things you can do: > > > 1) try out 5.12 > > > 2) attach `perf top` output or some other profiling for your 5.8 > > > 3) to have a more complete picture do 2) with 5.12 > > > > > > Let's find what's gone wrong > > > > > > -- > > > Pavel Begunkov > > > > > > > > -- > > Michael Stoler > > > > -- > Michael Stoler -- Michael Stoler