Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964829Ab2EWArS (ORCPT ); Tue, 22 May 2012 20:47:18 -0400 Received: from LGEMRELSE7Q.lge.com ([156.147.1.151]:51842 "EHLO LGEMRELSE7Q.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964793Ab2EWArP (ORCPT ); Tue, 22 May 2012 20:47:15 -0400 X-AuditID: 9c930197-b7be2ae000000ebb-28-4fbc338f8694 From: Namhyung Kim To: Stephane Eranian Cc: Peter Zijlstra , Arnaldo Carvalho de Melo , David Ahern , linux-kernel@vger.kernel.org, mingo@elte.hu Subject: Re: [PATCH v2 4/5] perf record: add meta-data support for pipe-mode References: <1337081295-10303-1-git-send-email-eranian@google.com> <1337081295-10303-5-git-send-email-eranian@google.com> <4FB32032.3000509@gmail.com> <4FB67DE5.8050000@gmail.com> <20120518171911.GH2636@infradead.org> <1337708035.9698.44.camel@twins> Date: Wed, 23 May 2012 09:45:12 +0900 In-Reply-To: (Stephane Eranian's message of "Tue, 22 May 2012 19:51:15 +0200") Message-ID: <87obpf209z.fsf@sejong.aot.lge.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.0.95 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1476 Lines: 35 Hi, On Tue, 22 May 2012 19:51:15 +0200, Stephane Eranian wrote: > On Tue, May 22, 2012 at 7:33 PM, Peter Zijlstra wrote: >> On Fri, 2012-05-18 at 14:19 -0300, Arnaldo Carvalho de Melo wrote: >> >>> PeterZ was the one objecting to adding more userspace only events, >> >> Ah, yes I was ;-) >> >> So uhm the argument was something like perf_event_type is a kernel enum >> and userspace stealing space there is going to get us into trouble >> eventually since userspace doesn't register its types in our enum. >> > Yes, I did not start this but I understand why it was done that way. > > The problem is that the headers as they are written to the file need > seeking in the file to update the offset table. That is NOT possible when > you operate in pipe mode. As such you need to inject the header infos > very much like kernel PERF_RECORD_*. That is also why you have > perf inject -b. Buildids are added at the end of the run in file mode, > and that's another seek to the offset table if I recall correctly. > IIUC, to add build-ids we should check all dso's whether hits or not, but it's not same as the case of meta-data since we can know it before processing. Am I missing something? Thanks, Namhyung -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/