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=-3.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 802E8C4360F for ; Mon, 18 Mar 2019 15:53:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4549D20880 for ; Mon, 18 Mar 2019 15:53:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="CJiyaqWB" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727844AbfCRPxK (ORCPT ); Mon, 18 Mar 2019 11:53:10 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:45686 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727623AbfCRPxC (ORCPT ); Mon, 18 Mar 2019 11:53:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-Id:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=KOI1sSR5MbmakeqqmiayCh7hafvj0XMrvXW7Klit8UU=; b=CJiyaqWBOEhOkZkCzMCYdOu02+ 7nlIKB9fMXEBOnv2Q22t9OfgIzqSWxFoawqEyglXW7RtixIm81JJrWTNRC5gCnzWi3VCemuA4kQei Ypa5fCKrlvUik7FME4th2l39GD+aGHu+JxA6YVx1uBQ+HVyQIOUJP36jEx9yrZEFORa4QiY47d+I/ EaqG+655OXvYdrpP9yUyhZb7h0Q7PYV2U4XAQai9OIISzWyCVwnQ4F8rZDnoUYVd0ZyUQDSxSzKtQ CTKt1sR5iaRB8XbXTicm3OFaWPWOsJaSZbo+dhe3Dt5BaYELaXZZgJKKb0A5B3TlyHKqPrL4zXRQs zDih9rLA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1h5uZ7-0006iV-D1; Mon, 18 Mar 2019 15:52:41 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 8449025E45D5F; Mon, 18 Mar 2019 16:52:38 +0100 (CET) Message-Id: <20190318155140.058627431@infradead.org> User-Agent: quilt/0.65 Date: Mon, 18 Mar 2019 16:38:42 +0100 From: Peter Zijlstra To: torvalds@linux-foundation.org, tglx@linutronix.de, hpa@zytor.com, julien.thierry@arm.com, will.deacon@arm.com, luto@amacapital.net, mingo@kernel.org, catalin.marinas@arm.com, james.morse@arm.com, valentin.schneider@arm.com, brgerst@gmail.com, jpoimboe@redhat.com, luto@kernel.org, bp@alien8.de, dvlasenk@redhat.com Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, dvyukov@google.com, rostedt@goodmis.org Subject: [PATCH 02/25] tracing: Improve "if" macro code generation References: <20190318153840.906404905@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org With CONFIG_PROFILE_ALL_BRANCHES, the "if" macro converts the conditional to an array index. This can cause GCC to create horrible code. When there are nested ifs, the generated code uses register values to encode branching decisions. Make it easier for GCC to optimize by keeping the conditional as a conditional rather than converting it to an integer. This shrinks the generated code quite a bit, and also makes the code sane enough for objtool to understand. Cc: rostedt@goodmis.org Cc: valentin.schneider@arm.com Cc: luto@amacapital.net Cc: brgerst@gmail.com Cc: catalin.marinas@arm.com Cc: mingo@kernel.org Cc: dvlasenk@redhat.com Cc: will.deacon@arm.com Cc: julien.thierry@arm.com Cc: torvalds@linux-foundation.org Cc: dvyukov@google.com Cc: bp@alien8.de Cc: tglx@linutronix.de Cc: james.morse@arm.com Cc: luto@kernel.org Cc: hpa@zytor.com Reported-by: Peter Zijlstra Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20190307174802.46fmpysxyo35hh43@treble --- include/linux/compiler.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -67,7 +67,7 @@ void ftrace_likely_update(struct ftrace_ .line = __LINE__, \ }; \ ______r = !!(cond); \ - ______f.miss_hit[______r]++; \ + ______r ? ______f.miss_hit[1]++ : ______f.miss_hit[0]++;\ ______r; \ })) #endif /* CONFIG_PROFILE_ALL_BRANCHES */