From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751846AbbGSE0c (ORCPT ); Sun, 19 Jul 2015 00:26:32 -0400 Received: from mail-pa0-f49.google.com ([209.85.220.49]:34552 "EHLO mail-pa0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750753AbbGSE0b (ORCPT ); Sun, 19 Jul 2015 00:26:31 -0400 Date: Sun, 19 Jul 2015 13:24:12 +0900 From: Namhyung Kim To: Masami Hiramatsu Cc: Hemant Kumar , Arnaldo Carvalho de Melo , Peter Zijlstra , linux-kernel@vger.kernel.org, Adrian Hunter , Ingo Molnar , Paul Mackerras , Jiri Olsa , Borislav Petkov Subject: Re: Re: [RFC PATCH perf/core v2 00/16] perf-probe --cache and SDT support Message-ID: <20150719042412.GB24219@danjae.kornet> References: <20150715091352.8915.87480.stgit@localhost.localdomain> <55A7215F.40803@linux.vnet.ibm.com> <55A874C6.5030202@hitachi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <55A874C6.5030202@hitachi.com> User-Agent: Mutt/1.5.23+89 (0255b37be491) (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Masami, On Fri, Jul 17, 2015 at 12:21:42PM +0900, Masami Hiramatsu wrote: > Now I'm thinking that we should avoid using %event syntax for perf-list > and perf-record to avoid confusion. For example, suppose that we have > "libfoo:bar" SDT event, when we just scanned the libfoo binary and > use it via perf-record, we'll run perf record -e "%libfoo:bar". > However, after we set the probe via perf-probe, we have to run > perf record -e "libfoo:bar". That difference looks no good. > So, I think in both case it should accept -e "libfoo:bar" syntax. I don't remember how the SDT events should be shown to users. Sorry if I'm missing something here. AFAIK an SDT event consists of a provider and an event name. So it can be simply 'provider:event' like tracepoints or 'binary:provider_event' like uprobes. I like the former because it's simpler but it needs to guarantee that it doesn't clash with existing tracepoints/[ku]probes. So IIUC we chose the '%' sign to distinguish them. But after setting a probe at it, the group name should be the binary name. So the whole event name might be changed, and this is not good. So we should use the latter form. But in this case, I think we need a way to distinguish provider and event names. Since the provider name also can include '_' characters in it. And maybe it still needs to distinguish an SDT event and its probe for some reason. In that case, we might use 'sdt:provider_event' form or something like that. Thanks, Namhyung > > In this series I've introduced %event syntax only to recall cached event > setting explicitly, because perf-probe is a lower layer tool to set up > new event. IMO, perf-list and perf-record should be higher tools which > handle abstract events.