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=-13.2 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 98CFDC433B4 for ; Sat, 1 May 2021 00:23:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 50541613EF for ; Sat, 1 May 2021 00:23:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231316AbhEAAYp (ORCPT ); Fri, 30 Apr 2021 20:24:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36938 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230298AbhEAAYn (ORCPT ); Fri, 30 Apr 2021 20:24:43 -0400 Received: from mail-lf1-x132.google.com (mail-lf1-x132.google.com [IPv6:2a00:1450:4864:20::132]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3EB15C06174A for ; Fri, 30 Apr 2021 17:23:54 -0700 (PDT) Received: by mail-lf1-x132.google.com with SMTP id z13so31688444lft.1 for ; Fri, 30 Apr 2021 17:23:54 -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=AVLNT3W+pl6I0XltrmL8EoY5HYXwqNz1G5YBmw1lrjM=; b=QnbdpOIiL+Wx63dWMjs3T0xwgF9xUMknZpk83NWFCvFAuAB4WjdLQYrShh45R4I7Cl W3fUFPnbmEklfWLTzAYqQROGnxgkDC3QcVJwWIUxRr57Ef1EzEmMw+R1G+4YVVtiQ2iy jhAoXmiWFXm7aGv8r0uVzISEtF5DjR9BPSOa1bFDRtbU3TkDWexPoeYKdkLTbu9FpgNQ yRalgj3JafNuYOLIU4ZJWIquMHerDJmy4Yz9Pj5/omjHExP2Zz/XHrYJ8wVoQ9bekKpV p9Mfq7ty0bNfTkqqNNRMiFDSskaYkUbzD0ysSKcJNSFUoKDuP8asBuf/SwZFlfiNz3Qm IK9A== 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=AVLNT3W+pl6I0XltrmL8EoY5HYXwqNz1G5YBmw1lrjM=; b=oqDItf/FNJ/3sJ11WpEEKgiCKZToQHznvACSdGZ5wXi03ITPsSupR2lZfAJREUgQ+G 71j5ZS6A4Rhg0SDU/lmfUTHa9Wb+7HdxDpL88t8swQ7P0XPeVIbcXY4tJuOWYuF+jVSy OyKMzJUzQx1+O/0kNxm3Gd6vOBjOPK92Tz7Jml12zol8n2+UHsPtGRhlEEZO0IiLFsAh 9xLmtR+e27p2hdWWipBA49Ch9Ch8Z8XL5LTcNWvO2oa8WuMOQtqLjBeRnKG8n01De3n5 B3yEcT5L7dr7EDjCKEWBzZyNX28XmOxLBPjr3asYe4fQBH3lSKLnXv73lNtOxHMmwq2o Wluw== X-Gm-Message-State: AOAM532iSqZCz19UU70M1p5lUWzwUhLGXTYmTZmufaIpnla2kufME8J1 EmFXirHlsJKC6DOuAKARitYssOJFE6qC5sC3T/sCIg== X-Google-Smtp-Source: ABdhPJwCAsbL0cMTPY3WmC0LihDrNqp+6gvyh+PpFc7K9d+4n1Hjw/0GE7fBpMxFn82Ki8Ied6SwlO9OTyRZldTTya8= X-Received: by 2002:ac2:5979:: with SMTP id h25mr5078255lfp.297.1619828631049; Fri, 30 Apr 2021 17:23:51 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Nick Desaulniers Date: Fri, 30 Apr 2021 17:23:40 -0700 Message-ID: Subject: Re: Very slow clang kernel config .. To: Linus Torvalds , Masahiro Yamada Cc: Nathan Chancellor , Linux Kernel Mailing List , clang-built-linux Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Apr 30, 2021 at 5:19 PM Nick Desaulniers wrote: > > A quick: > $ perf record -e cycles:pp --call-graph lbr make LLVM=1 LLVM_IAS=1 > -j72 allmodconfig > $ perf report --no-children --sort=dso,symbol > shows: > 2.35% [unknown] [k] 0xffffffffabc00fc7 > + 2.29% libc-2.31.so [.] _int_malloc > 1.24% libc-2.31.so [.] _int_free > + 1.23% ld-2.31.so [.] do_lookup_x ^ bfd > + 1.14% libc-2.31.so [.] __strlen_avx2 > + 1.06% libc-2.31.so [.] malloc > + 1.03% clang-13 [.] llvm::StringMapImpl::LookupBucketFor > 1.01% libc-2.31.so [.] __memmove_avx_unaligned_erms > + 0.76% conf [.] yylex ^ kconfig > + 0.68% clang-13 [.] llvm::Instruction::getNumSuccessors > + 0.63% libbfd-2.35.2-system.so [.] bfd_hash_lookup ^ bfd > + 0.63% clang-13 [.] llvm::PMDataManager::findAnalysisPass ^ this is another suspect one to me, though perhaps I should isolate out the HOSTCC invocations vs cc-option checks. Should retest with just CC=clang rather than HOSTCC=clang set via LLVM=1. > + 0.63% ld-2.31.so [.] _dl_lookup_symbol_x ^ bfd > 0.62% libc-2.31.so [.] __memcmp_avx2_movbe > 0.60% libc-2.31.so [.] __strcmp_avx2 > + 0.56% clang-13 [.] llvm::ValueHandleBase::AddToUseList > + 0.56% clang-13 [.] > llvm::operator== llvm::DenseMapInfo, llvm::detail::Dense > 0.53% clang-13 [.] > llvm::SmallPtrSetImplBase::insert_imp_big -- Thanks, ~Nick Desaulniers