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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS 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 E8A9EC433F5 for ; Fri, 24 Aug 2018 21:09:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8DB3920A8B for ; Fri, 24 Aug 2018 21:09:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=maine.edu header.i=@maine.edu header.b="EmOdLT1A" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8DB3920A8B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=maine.edu 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 S1727414AbeHYAps (ORCPT ); Fri, 24 Aug 2018 20:45:48 -0400 Received: from mail-qt0-f196.google.com ([209.85.216.196]:36782 "EHLO mail-qt0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726850AbeHYAps (ORCPT ); Fri, 24 Aug 2018 20:45:48 -0400 Received: by mail-qt0-f196.google.com with SMTP id t5-v6so11700398qtn.3 for ; Fri, 24 Aug 2018 14:09:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=maine.edu; s=google; h=from:date:to:cc:subject:in-reply-to:message-id:references :user-agent:mime-version; bh=NFmMHGWpphaZlRgkjWQwaHICII65kQYMGQOqE4IfmG8=; b=EmOdLT1AlXq0oOgtTnd50bH5IltK1jg7l9842IvfQWn0JUyela/RpnCUmI02i1R1+N dqHCtaOYq2URxwSSgYwLJ2rXHImFA85aowAjNhxXA1bkXBOBxa+kSEouhqqRKdxCwxas 3By0MvqDyY7fkT2AfqbOD8nm553/ows0n7zr8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:date:to:cc:subject:in-reply-to:message-id :references:user-agent:mime-version; bh=NFmMHGWpphaZlRgkjWQwaHICII65kQYMGQOqE4IfmG8=; b=F4xZpbf8jt8XstiXSIF09XvZxKm2PEUTIcZ+oo0zyOQKB5gsFFi28jGwhI5draE+7H 1BSyf8QuRGCBeHG+OdHXRswutyS5poodFEKFXZAfFXT9AqJXP3gm5TZ9+uL/80ek0mjZ lWdcXJwHekSBCYYH7Y6QMAmRgn98XTSdACqHGx6L2F7vEzL26PsYOXORqVdX7bK5Ho7Z 5JueAWkPrxFx0E6cj6BEeWwZvcbfOYO58zgU6VG+GPZgd50D+PajTSzikzZ9rpoQuArX ArOwy3greEwFPTXVEOaGnTFbENcgerAHScrwbX0PnGVJB+LuyuHpLNzM3FbAgWXEn8Hj o5+w== X-Gm-Message-State: APzg51BhjZ2WQ6CYLdehrnRmBoJZpDIB4+8dPGOHJ5QwBJUERoviiGyf 7v4eo1skYzpmG5z09+qv3sw/yA== X-Google-Smtp-Source: ANB0VdYIFgAtlH9ytK9VcN+YX57VmlCQOaZWmuCzeuYDVyhdoxvH2BfpsVEwHxvzWCvEsiuUx9qFMA== X-Received: by 2002:aed:22e5:: with SMTP id q34-v6mr3785744qtc.179.1535144969412; Fri, 24 Aug 2018 14:09:29 -0700 (PDT) Received: from macbook-air (weaver.eece.maine.edu. [130.111.218.23]) by smtp.gmail.com with ESMTPSA id s35-v6sm5511261qtj.79.2018.08.24.14.09.27 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 24 Aug 2018 14:09:28 -0700 (PDT) From: Vince Weaver X-Google-Original-From: Vince Weaver Date: Fri, 24 Aug 2018 17:09:27 -0400 (EDT) X-X-Sender: vince@macbook-air To: Peter Zijlstra 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 In-Reply-To: <20180824085042.GL24124@hirez.programming.kicks-ass.net> Message-ID: References: <20180824085042.GL24124@hirez.programming.kicks-ass.net> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. 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. Vince