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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 E7AB9C677E4 for ; Mon, 8 Oct 2018 15:13:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B90922075C for ; Mon, 8 Oct 2018 15:13:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B90922075C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726692AbeJHWZN (ORCPT ); Mon, 8 Oct 2018 18:25:13 -0400 Received: from mx1.redhat.com ([209.132.183.28]:42396 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726367AbeJHWZL (ORCPT ); Mon, 8 Oct 2018 18:25:11 -0400 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.24]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 92EFD8831F; Mon, 8 Oct 2018 15:13:00 +0000 (UTC) Received: from krava (unknown [10.43.17.152]) by smtp.corp.redhat.com (Postfix) with SMTP id E57E43091888; Mon, 8 Oct 2018 15:12:58 +0000 (UTC) Date: Mon, 8 Oct 2018 17:12:58 +0200 From: Jiri Olsa To: Alexey Budankov Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Alexander Shishkin , Namhyung Kim , Andi Kleen , linux-kernel Subject: Re: [PATCH v11 1/3]: perf util: map data buffer for preserving collected data Message-ID: <20181008151258.GI18757@krava> References: <7d42aa80-8e69-44e4-b963-e8ef89df2099@linux.intel.com> <0ff162a6-67ab-9e73-8d7e-fa57c932ee45@linux.intel.com> <20181008105057.GD17270@krava> <20181008123859.GD18757@krava> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.24 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Mon, 08 Oct 2018 15:13:00 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 08, 2018 at 05:43:38PM +0300, Alexey Budankov wrote: > Hi, > > On 08.10.2018 15:38, Jiri Olsa wrote: > > On Mon, Oct 08, 2018 at 03:03:18PM +0300, Alexey Budankov wrote: > > >> > >> Well, let's go with stub functions design as opposite to pure > >> conditional compilation. However this may, probably, result in > >> unintended Perf tool binary size growth, even if NO_AIO is > >> defined during compilation. > > > > hum, empty functions are be optimized out > > Yes, but there will be references to stubs in else branch of > record__mmap_read_evlist() so I am not sure that *all* compilers > are smart enough to recognize and still optimize it out. well, kernel is doing that and it seem to be fine, so I wouldn't worry about it jirka