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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no 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 1C71DC433E0 for ; Sat, 13 Mar 2021 08:52:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DFED764F1D for ; Sat, 13 Mar 2021 08:52:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230380AbhCMIwA (ORCPT ); Sat, 13 Mar 2021 03:52:00 -0500 Received: from mail.skyhub.de ([5.9.137.197]:47096 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230114AbhCMIvh (ORCPT ); Sat, 13 Mar 2021 03:51:37 -0500 Received: from zn.tnic (p4fed3942.dip0.t-ipconnect.de [79.237.57.66]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 603BF1EC008F; Sat, 13 Mar 2021 09:51:36 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1615625496; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=StXyIIfqkxQHxQ5eh5tIDHPBxAG+44uelUfk7AF9bs4=; b=QxNPBfDwXJp2pCLJl7x8ymZD5bJttYMWExFOIJTtuT47G7HhAN1nm4XJWAw+FXsIYVA2Wy bd9lNprMeSPtA4eSrxWB20QCPmHiKMJxXyyF8ykbtyhzVnmP5PnA837qX9xPpnZL6zykFM 5OQPDenNjIWs8G2tnTEbqNtGD5vwX/k= Date: Sat, 13 Mar 2021 09:49:23 +0100 From: Borislav Petkov To: Sedat Dilek Cc: Peter Zijlstra , x86@kernel.org, rostedt@goodmis.org, hpa@zytor.com, torvalds@linuxfoundation.org, linux-kernel@vger.kernel.org, linux-toolchains@vger.kernel.org, jpoimboe@redhat.com, alexei.starovoitov@gmail.com, mhiramat@kernel.org Subject: Re: [PATCH 0/2] x86: Remove ideal_nops[] Message-ID: <20210313084923.GA16144@zn.tnic> References: <20210312113253.305040674@infradead.org> <20210312205914.GG22098@zn.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-toolchains@vger.kernel.org On Sat, Mar 13, 2021 at 06:26:15AM +0100, Sedat Dilek wrote: > x86/jump_label: Mark arguments as const to satisfy asm constraints Where do I find this patch? > x86: Remove dynamic NOP selection > objtool,x86: Use asm/nops.h > > My benchmark was to build a Linux-kernel with LLVM/Clang v12.0.0-rc3 > on Debian/testing AMD64. > > Patchset applied for a first build: > > Performance counter stats for 'make V=1 -j4 LLVM=1 LLVM_IAS=1 > PAHOLE=/opt/pahole/bin/pahole LOCALVERSION=-7-amd64-clang12-cfi > KBUILD_VERBOSE=1 KBUILD_BUILD_HOST=iniza There's a reason I have -s for silent in the build - printing output during the build creates a *lot* of variance. And you have excessive printing with V=1 and KBUILD_VERBOSE=1. Also, you need to repeat those workloads a couple of times - one is not enough. That's why I have --repeat 5 in there. Also, you need --pre=/root/bin/pre-build-kernel.sh where that script is: --- #!/bin/bash echo $0 make -s clean echo 3 > /proc/sys/vm/drop_caches --- so that you can avoid pagecache influence. Lemme rerun here with clang. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette