From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752250AbcELG3F (ORCPT ); Thu, 12 May 2016 02:29:05 -0400 Received: from smtprelay4.synopsys.com ([198.182.47.9]:43466 "EHLO smtprelay.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751594AbcELG3C (ORCPT ); Thu, 12 May 2016 02:29:02 -0400 Subject: Re: [RFC 2/2] perf/core: change errno for sampling event not supported in hardware To: Peter Zijlstra References: <1462786660-2900-1-git-send-email-vgupta@synopsys.com> <1462786660-2900-3-git-send-email-vgupta@synopsys.com> <5730C79F.3060307@synopsys.com> <20160511193627.GH3190@twins.programming.kicks-ass.net> CC: , Vince Weaver , , , , Newsgroups: gmane.linux.kernel.arc,gmane.linux.kernel,gmane.linux.kernel.perf.user From: Vineet Gupta Message-ID: <5734229B.90706@synopsys.com> Date: Thu, 12 May 2016 11:58:43 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.7.2 MIME-Version: 1.0 In-Reply-To: <20160511193627.GH3190@twins.programming.kicks-ass.net> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.12.197.158] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thursday 12 May 2016 01:06 AM, Peter Zijlstra wrote: > On Mon, May 09, 2016 at 10:53:43PM +0530, Vineet Gupta wrote: > >> > Right thats what I feared. But hold on, I don't think we need to change the ABI to >> > achieve what we want. Gosh why did I even take that path. >> > >> > Currently the errno switch case in perf_evsel__open_strerror() in doesn't handle >> > ENOTSUPP. So how about we add that - augmented with the same sample_period !0 >> > check to barf for lack of sampling support. >> > >> > Do you see anything wrong with that ? > > Should work I think. Tried that and doesn't even compile. Reconfirms what Vince said, ENOTSUPP is not exposed to userspace (being in include/linux and not include/uapi/linux)