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=-13.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL 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 A2104C2B9F4 for ; Mon, 14 Jun 2021 18:08:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8153C61075 for ; Mon, 14 Jun 2021 18:08:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234606AbhFNSKe (ORCPT ); Mon, 14 Jun 2021 14:10:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48282 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233427AbhFNSKd (ORCPT ); Mon, 14 Jun 2021 14:10:33 -0400 Received: from mail-lj1-x233.google.com (mail-lj1-x233.google.com [IPv6:2a00:1450:4864:20::233]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 94914C061767 for ; Mon, 14 Jun 2021 11:08:13 -0700 (PDT) Received: by mail-lj1-x233.google.com with SMTP id b37so5356821ljr.13 for ; Mon, 14 Jun 2021 11:08:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=q/XB3mh4kqA0R3Mq5xG+IQPk2u072QCh1Aa1N8SVimI=; b=gNoMBqwIekxVN4ZTQA2lb+R20pn6emj+cRv+063F8GUQEh+FfehSxGO7Xfa3xVcU3y JNiHA/bieZlQ0jgmetM3eerqFAtGCVDc8wlzQ3M/mwfNPBGiWljejiloap0qpolaWRwM zyFvn32ZAv4OTwgqbKcKUFRfB2w3GYsBl0Ohsk903f3S2aJ8ihqajen4jcWO3pTZeTl4 m993LukbpLj1Ytei7kh8YWEerFqD3osLEVw7AF8D6GGia1vZCt8v8SzbH6rbqhKztVFJ 7UMl8nAKNXJuvuZDmibTlloR0VSSNTu7UEsrHWjpM6yBK+GGIpZf5DhbG3UVlYNesjYH dONw== 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=q/XB3mh4kqA0R3Mq5xG+IQPk2u072QCh1Aa1N8SVimI=; b=mhfzF64eRGP9ZxMqLQDWyn5+ltvHfuOvFu62NkHIp8gSxoytXu2TQs3NAfnKkM0/dy zex8ImACyAvwuq5h1poP3yoKN99wQyTJcdjoJdmXb9byAUL4yiNPM/o+rpVUYs2FH4gc kp1/o3eFPDFYbdMJq9U6FoivzDJUxKzzotERZ2xJCNNaEvN9EKwZBVv1yB6imWnpomZF I47u3DCy6XEZ8JUSpkQ/BVmy/fRgFYkOJ3clZQVNSC0nAGqaRoBvWSJzcvlXuNIaD3dg abcbI2V3QRjPRjRwxpIOlc2Ar0gtWu0fOPjMJnuU1fb28jGG2/PwVwgMuiQmREYO7zJU IHAA== X-Gm-Message-State: AOAM531luGRgOBp1PY6ig5cvPRVAoRVrXBP4iZR669SbK+Ig5qm5jB/0 3O+XmyNrrd0ORK2L+KyF1B+8YXbXRbI8KPTZJiC2Gw== X-Google-Smtp-Source: ABdhPJxKUKdlT+gTIv6tps2+MYGOK2jI4OTbw6VDol/+bdJyGm1oEKl+AJBHsonScc4F4P1rTyqrJq3Fw4OFoMUrzZ0= X-Received: by 2002:a05:651c:1111:: with SMTP id d17mr14547090ljo.116.1623694091627; Mon, 14 Jun 2021 11:08:11 -0700 (PDT) MIME-Version: 1.0 References: <20210612202505.GG68208@worktop.programming.kicks-ass.net> <202106140817.F584D2F@keescook> <20210614153545.GA68749@worktop.programming.kicks-ass.net> <202106140921.5E591BD@keescook> In-Reply-To: <202106140921.5E591BD@keescook> From: Nick Desaulniers Date: Mon, 14 Jun 2021 11:07:59 -0700 Message-ID: Subject: Re: [PATCH v9] pgo: add clang's Profile Guided Optimization infrastructure To: Kees Cook Cc: Peter Zijlstra , Marco Elver , Bill Wendling , Jonathan Corbet , Masahiro Yamada , Linux Doc Mailing List , LKML , Linux Kbuild mailing list , clang-built-linux , Andrew Morton , Nathan Chancellor , Sami Tolvanen , Fangrui Song , "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , Andrey Konovalov , Dmitry Vyukov , Johannes Berg , oberpar@linux.vnet.ibm.com, linux-toolchains@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-toolchains@vger.kernel.org On Mon, Jun 14, 2021 at 9:23 AM Kees Cook wrote: > > On Mon, Jun 14, 2021 at 05:35:45PM +0200, Peter Zijlstra wrote: > > On Mon, Jun 14, 2021 at 08:26:01AM -0700, Kees Cook wrote: > > > So, AFAICT, the original blocking issue ("PGO does not respect noinstr") > > > is not actually an issue (noinstr contains notrace, which IS respected > > > by PGO[2]), I think this is fine to move forward. > > > > It is *NOT*: https://godbolt.org/z/9c7xdvGd9 > > > > Look at how both compilers generate instrumentation in the no_instr() > > function. > > Well that's disappointing. I'll put this on hold until Clang can grow an > appropriate attribute (or similar work-around). Thanks for catching > that. Cross referencing since these two threads are related. https://lore.kernel.org/lkml/CAKwvOdmPTi93n2L0_yQkrzLdmpxzrOR7zggSzonyaw2PGshApw@mail.gmail.com/ -- Thanks, ~Nick Desaulniers