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=-2.2 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,T_DKIM_INVALID, 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 303BBC43334 for ; Mon, 27 Aug 2018 07:52:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E2095208DA for ; Mon, 27 Aug 2018 07:52:56 +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="TsgX4KbE" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E2095208DA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org 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 S1727322AbeH0LiY (ORCPT ); Mon, 27 Aug 2018 07:38:24 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:46334 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727101AbeH0LiX (ORCPT ); Mon, 27 Aug 2018 07:38:23 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=scKW0pvD6ySwQo06heKJnd8A3zFX67evTMYdbm/uWds=; b=TsgX4KbEckS2CKAt+VLmVOvap aULIG5TGcsBzSgbdGHV7Lib565AgUGr2RaLy6itkQDouxQqwO62zp5fN5aJGYiKG6fI2Uu8sJxnJ9 fP64HmoVdJGZrroDwMVe7khlNAyoPm0ErbxU8cDFvukY3VZNjxzZnEP1KRkN6ElMQzKUi/9bIA7Oa Jlx5ug14fLZnjZp6Gs/yCOvgoAYTdkb4F9sJLSeNOki3DDkFNMScjjTJFLfCXt8im3Pn1/DJ/UQ+p 8LuXb9U1EuSDvvEFFhRcQWWZkV3Hjf2QZ4FiLh0wLb/ZJn0yaN+EBBSp45FCvkFO6Vx51BFZ6S3ri a/8IWjjzw==; 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 1fuCKO-0005Wt-7z; Mon, 27 Aug 2018 07:52:48 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 8C54F2024EFCD; Mon, 27 Aug 2018 09:52:46 +0200 (CEST) Date: Mon, 27 Aug 2018 09:52:46 +0200 From: Peter Zijlstra To: Vince Weaver Cc: linux-kernel@vger.kernel.org, Josh Poimboeuf , Alexander Shishkin , Andy Lutomirski , Arnaldo Carvalho de Melo , Arnaldo Carvalho de Melo , Jiri Olsa , Linus Torvalds , Stephane Eranian , Thomas Gleixner , Ingo Molnar Subject: Re: [perf] perf_event.h ABI visibility question Message-ID: <20180827075246.GX24124@hirez.programming.kicks-ass.net> References: <20180824085042.GL24124@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 24, 2018 at 05:09:27PM -0400, Vince Weaver wrote: > On Fri, 24 Aug 2018, Peter Zijlstra wrote: > > > > +++ b/include/uapi/linux/perf_event.h > > > @@ -143,6 +143,8 @@ enum perf_event_sample_format { > > > PERF_SAMPLE_PHYS_ADDR = 1U << 19, > > > > > > PERF_SAMPLE_MAX = 1U << 20, /* non-ABI */ > > > + > > > + __PERF_SAMPLE_CALLCHAIN_EARLY = 1ULL << 63, > > > }; > > > > > > > Hurphm.. visible yes, but as you say, also quite useless. Does it really > > make sense to document that? > > Well, it should probably be documented either in the manpage or else in > perf_event.h (even if it's just "internal use, don't use") as we can't > really expect people to download a git tree and do a git-blame to try to > figure out what this mysterious field is all about. Something like so then? diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h index eeb787b1c53c..f35eb72739c0 100644 --- a/include/uapi/linux/perf_event.h +++ b/include/uapi/linux/perf_event.h @@ -144,7 +144,7 @@ enum perf_event_sample_format { PERF_SAMPLE_MAX = 1U << 20, /* non-ABI */ - __PERF_SAMPLE_CALLCHAIN_EARLY = 1ULL << 63, + __PERF_SAMPLE_CALLCHAIN_EARLY = 1ULL << 63, /* non-ABI; internal use */ }; /* > Also, this change increased the size of the enum from 32 to 64 bits on > 32-bit machines, though that only really matters if the user is doing > something really weird with enum variables. Yeah, since the target variable is a u64 I really can't be bothered with that.