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=-8.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 69E9CC433E0 for ; Thu, 6 Aug 2020 15:20:07 +0000 (UTC) Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 86D3C23136 for ; Thu, 6 Aug 2020 15:20:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=intel-com.20150623.gappssmtp.com header.i=@intel-com.20150623.gappssmtp.com header.b="tGrB7Z7W" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 86D3C23136 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvdimm-bounces@lists.01.org Received: from ml01.vlan13.01.org (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 062FC12A73075; Thu, 6 Aug 2020 08:20:07 -0700 (PDT) Received-SPF: Pass (mailfrom) identity=mailfrom; client-ip=2a00:1450:4864:20::62e; helo=mail-ej1-x62e.google.com; envelope-from=dan.j.williams@intel.com; receiver= Received: from mail-ej1-x62e.google.com (mail-ej1-x62e.google.com [IPv6:2a00:1450:4864:20::62e]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 20BA712A7306F for ; Thu, 6 Aug 2020 08:20:03 -0700 (PDT) Received: by mail-ej1-x62e.google.com with SMTP id f24so30253085ejx.6 for ; Thu, 06 Aug 2020 08:20:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=intel-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=27KOdDBMR58YvRnK7H5/nd9yUqjH+UuYcfpnQiwOOLU=; b=tGrB7Z7WS0HHtWrS+RAu0IAYwU8Nad8rwMZdG73SY5x2ARE0d1FqXwWCLzD3UMrdlR 6Kn0kjJyU3Zbj6OubM+TRf7kg41JZspNfLxofrrUzUQMRrYpHgt6yi61+Rzw0TSxyySG ZrV978lfm55ZcESwNGZp975asvMxzL4xk01lDpBkj9kuUKt1y4ZnLs/xyWsATvELhJk1 kFLFuZbHju979DVXXQ3lQhqftMpDMvL9oc++9T2qcgkhq/HPw08XX+JQDNIRTow6uAXN WiVbdduH+x+EmynnvVmeE/Jlm8OcHRV5jln6i5lJFo17YjLsUFxNhJ1YjoX3Mjouet1b 4MZA== 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=27KOdDBMR58YvRnK7H5/nd9yUqjH+UuYcfpnQiwOOLU=; b=mbjuD93MmBXElZSMfaDmO8EYbamJjuWWLrJ2QmYT+sALQ7Bo8gIcU3GS7Ug2C5Jsqo y8mMmx3Zn5oB/RvmoTc3tW+Bt+EdGsXbf0Yot7+6iRlqifCpPxqNuangTduCJ01Q4ARG RUTY/V5HO/sxW2uSR2BBO/L4jM+aRQG0XcoAWUuwSC0QErSlFnWzD257m9klr1R2aKoa etkl9YDLEAT3pV0hioOvDs4naUXNQQhyyMOe+unbFAF9i2FEcF1vBp1WtsPPivpa1g77 PqjvhX4Q2Qfaui3ke70423UZOsXKFuWVUNnAf2WNJZJeyd+uOTZ5w+Br4pWGB1N0oDqx MbvA== X-Gm-Message-State: AOAM531e5PYxgDzhuOagOt255zIQXPuN+wQoMcG/S48B3gfAOw9Oxm/X qnqeSW+i5Zcc+bWusFGAvhufdg5JoJ0d1csb46t1Kw== X-Google-Smtp-Source: ABdhPJzrlkvHWWpq4WM0aG15rib8qGzmbNy1T+8TCAaz/ASsMen1gmJIqTYuiQwAEJfL8+D0y5EKRfUDgIokuAOiI0I= X-Received: by 2002:a17:906:38d8:: with SMTP id r24mr4667542ejd.341.1596727202027; Thu, 06 Aug 2020 08:20:02 -0700 (PDT) MIME-Version: 1.0 References: <159630256804.3143511.8894023468833792004.stgit@dwillia2-desk3.amr.corp.intel.com> <20200803094257.GA23458@shao2-debian> <20200806133452.GA2077191@gmail.com> In-Reply-To: <20200806133452.GA2077191@gmail.com> From: Dan Williams Date: Thu, 6 Aug 2020 08:19:52 -0700 Message-ID: Subject: Re: [x86/copy_mc] a0ac629ebe: fio.read_iops -43.3% regression To: Ingo Molnar Message-ID-Hash: RPEHRGZIAIGWSL2RBZJ5KGS46QGXHJVN X-Message-ID-Hash: RPEHRGZIAIGWSL2RBZJ5KGS46QGXHJVN X-MailFrom: dan.j.williams@intel.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; suspicious-header CC: kernel test robot , Thomas Gleixner , Ingo Molnar , X86 ML , stable , Borislav Petkov , "H. Peter Anvin" , Andy Lutomirski , Peter Zijlstra , Linus Torvalds , Tony Luck , Erwin Tsaur , linux-nvdimm , Linux Kernel Mailing List , 0day robot , lkp@lists.01.org X-Mailman-Version: 3.1.1 Precedence: list List-Id: "Linux-nvdimm developer list." Archived-At: List-Archive: List-Help: List-Post: List-Subscribe: List-Unsubscribe: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Thu, Aug 6, 2020 at 6:35 AM Ingo Molnar wrote: > > > * kernel test robot wrote: > > > Greeting, > > > > FYI, we noticed a -43.3% regression of fio.read_iops due to commit: > > > > > > commit: a0ac629ebe7b3d248cb93807782a00d9142fdb98 ("x86/copy_mc: Introduce copy_mc_generic()") > > url: https://github.com/0day-ci/linux/commits/Dan-Williams/Renovate-memcpy_mcsafe-with-copy_mc_to_-user-kernel/20200802-014046 > > > > > > in testcase: fio-basic > > on test machine: 96 threads Intel(R) Xeon(R) Gold 6252 CPU @ 2.10GHz with 256G memory > > with following parameters: > > So this performance regression, if it isn't a spurious result, looks > concerning. Is this expected? This is not expected and I think delays these patches until I'm back from leave in a few weeks. I know that we might lose some inlining effect due to replacing native memcpy, but I did not expect it would have an impact like this. In my testing I was seeing a performance improvement from replacing the careful / open-coded copy with rep; mov;, which increases the surprise of this result. _______________________________________________ Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org To unsubscribe send an email to linux-nvdimm-leave@lists.01.org