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=-12.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 9424FC433E0 for ; Thu, 21 Jan 2021 09:38:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3747023975 for ; Thu, 21 Jan 2021 09:38:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728892AbhAUJhh (ORCPT ); Thu, 21 Jan 2021 04:37:37 -0500 Received: from cmyk.emenem.pl ([217.79.154.63]:37580 "EHLO smtp.emenem.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728673AbhAUJal (ORCPT ); Thu, 21 Jan 2021 04:30:41 -0500 X-Virus-Scanned: amavisd-new at emenem.pl Received: from [192.168.1.10] (50-78-106-33-static.hfc.comcastbusiness.net [50.78.106.33]) (authenticated bits=0) by cmyk.emenem.pl (8.15.2/8.15.2) with ESMTPSA id 10L9TPgd010680 (version=TLSv1.2 cipher=AES128-GCM-SHA256 bits=128 verify=NO); Thu, 21 Jan 2021 10:29:28 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ans.pl; s=20190507; t=1611221369; bh=Lq22v3RkUxykYRJ6+6won8Dh0Xg+coKzvzR7UFLaOq0=; h=Subject:To:Cc:References:From:Date:In-Reply-To; b=gvwdg0mYxYF6epudhRb/4HyXhJpyXYsKV0HFgTgRtCY5rjRKVX5ewTPswTFxWbFo4 wlyvcNnzoF/pq7jH8sZwW9vl2R+D1XNlkYrCF5ZhaOWl8ALKCzM8mlej0lpluUFNW1 gWUq3l7y7ppvper7MabC2wJI8JX5AeDWXIC4dgJs= Subject: Re: [PATCH v3 0/4] x86/fpu: Reduce unnecessary FNINIT and MXCSR usage To: Andy Lutomirski , x86@kernel.org Cc: LKML , Krzysztof Mazur , Arnd Bergmann References: From: =?UTF-8?Q?Krzysztof_Ol=c4=99dzki?= Message-ID: <3e54439d-24cf-8b9d-6b5a-efb756f3a5be@ans.pl> Date: Thu, 21 Jan 2021 01:29:23 -0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021-01-20 at 21:09, Andy Lutomirski wrote: > This series fixes two regressions: a boot failure on AMD K7 and a > performance regression on everything. > > I did a double-take here -- the regressions were reported by different > people, both named Krzysztof :) > > Changes from v2: > - Tidy up the if statements (Sean) > - Changelog and comment improvements (Boris) > > Changes from v1: > - Fix MMX better -- MMX really does need FNINIT. > - Improve the EFI code. > - Rename the KFPU constants. > - Changelog improvements. > > Andy Lutomirski (4): > x86/fpu: Add kernel_fpu_begin_mask() to selectively initialize state > x86/mmx: Use KFPU_387 for MMX string operations > x86/fpu: Make the EFI FPU calling convention explicit > x86/fpu/64: Don't FNINIT in kernel_fpu_begin() Hi Andy, I have tested the new patchset on the following CPUs running 5.4.90 (with some adjustments required for it to apply) and 5.10.9 kernels: - AMD Phenom(tm) II X3 B77 Processor (family: 0x10, model: 0x4, stepping: 0x3) - Intel(R) Xeon(R) CPU 3070 @ 2.66GHz (family: 0x6, model: 0xf, stepping: 0x6) - Intel(R) Xeon(R) CPU E3-1280 V2 @ 3.60GHz (family: 0x6, model: 0x3a, stepping: 0x9) For all of them, it was possible to recover most of the performance lost due to the introduction of "Reset MXCSR to default in kernel_fpu_begin": - B77: 90% instead of 82% for prefetch64-sse, 92% instead of 84% for generic_sse - 3070: 93% instead of 86% for prefetch64-sse, 93% instead of 88% for generic_sse - 1280v2: 99% instead of 88% for prefetch64-sse, 99% instead of 88% for generic_sse. For some reason, 1280v2 (Ivy Bridge) sees almost no regression for prefetch64-sse and generic_sse. The only issue is that AVX is still at 67% of its original performance. This is of course better compared to 60%. There is no AVX on the other 2 CPUs. I was using 64 bit kernels for testing, please let me know if 32 bit is also needed. Tested-by: Krzysztof Piotr Olędzki Thanks, Krzysztof