Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757000Ab1DGUZ2 (ORCPT ); Thu, 7 Apr 2011 16:25:28 -0400 Received: from smtp-out.google.com ([216.239.44.51]:19949 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756947Ab1DGUZ0 convert rfc822-to-8bit (ORCPT ); Thu, 7 Apr 2011 16:25:26 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=google.com; s=beta; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type:content-transfer-encoding; b=dOQxO8nYDo0tqn9OnHChsgy+biVFyd67/7DQ7gCV8vAl5E3DQ6Ba7S3p2h2U7yGyIB 0g0SwrJd3wXDx22ErirA== MIME-Version: 1.0 In-Reply-To: <20110407142605.GC1798@nowhere> References: <1300746846-28245-1-git-send-email-dhsharp@google.com> <20110407142605.GC1798@nowhere> From: David Sharp Date: Thu, 7 Apr 2011 13:25:04 -0700 Message-ID: Subject: Re: [PATCH perf 0/2] perf: trace-event-parse: support more operators and print formats To: Frederic Weisbecker Cc: linux-kernel@vger.kernel.org, mrubin@google.com, Arnaldo Carvalho de Melo , Steven Rostedt , Ingo Molnar , Stephane Eranian Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2249 Lines: 56 On Thu, Apr 7, 2011 at 7:26 AM, Frederic Weisbecker wrote: > On Wed, Apr 06, 2011 at 07:01:40PM -0700, David Sharp wrote: >> Hi, any feedback on these patches? I think it's important that perf >> and trace-cmd don't drift in the syntax they accept. >> >> d# > > Sorry, I forgot these. > >> On Mon, Mar 21, 2011 at 3:34 PM, David Sharp wrote: >> > These patches correspond to similar patches recently applied to trace-cmd >> > >> > [ Re-sending with more Cc's ] >> > >> > Cc: Arnaldo Carvalho de Melo >> > Cc: Frederic Weisbecker >> > Cc: Steven Rostedt >> > Cc: Ingo Molnar >> > Cc: Stephane Eranian >> > >> > >> > David Sharp (2): >> >  perf: trace-event-parse: support additional operators: '!', '~',  and >> >    '!=' >> >  perf: trace-event-parse: support printing short fields > > So we now have trace events that use these new operations? Which ones? > A quick grep on "TP_printk" and "!" doesn't give me any result, probably > because TP_printk is often multiline. > We (google) have some events that use '~' and '!', and I threw in '!=' mostly because it needed to be differentiated from '!' during tokenizing. We set the MSB of the syscall number in raw_syscalls events to indicate a compat syscall, and use '~' and '!' (and '&' and '>>') to extract the bit. eg, for sys_exit: print fmt: "NR %ld = %ld isCompat: %d", REC->id & (~0UL>>1), REC->ret, !!(REC->id & ~(~0UL>>1)) Patches for this will be forthcoming, but, you know: time. If our internally-added events are not sufficient reason, I think it still makes sense to support as much of the C expression syntax as reasonable. Leaving holes in the syntax mostly just causes frustration when these operators would be useful. And since they do work with the in-kernel output (which has the whole compiler to leverage), use of unsupported operators can go unnoticed for quite a while. Thanks, d# -- 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/