From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964955AbeEXHMJ (ORCPT ); Thu, 24 May 2018 03:12:09 -0400 Received: from merlin.infradead.org ([205.233.59.134]:58860 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935346AbeEXHMG (ORCPT ); Thu, 24 May 2018 03:12:06 -0400 Date: Thu, 24 May 2018 09:11:52 +0200 From: Peter Zijlstra To: Cong Wang Cc: Ivan Babrou , LKML , Paul Turner , Mike Galbraith , Thomas Gleixner , Ingo Molnar Subject: Re: [PATCH 3/3] sched/fair: add tracepoints for cfs throttle Message-ID: <20180524071152.GB12198@hirez.programming.kicks-ass.net> References: <20180522062017.5193-1-xiyou.wangcong@gmail.com> <20180522062017.5193-4-xiyou.wangcong@gmail.com> <20180523090944.GV12217@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.5 (2018-04-13) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 23, 2018 at 09:40:47PM -0700, Cong Wang wrote: > On Wed, May 23, 2018 at 2:09 AM, Peter Zijlstra wrote: > > Yeah, don't worry. I hate tracepoints, I regret the existing ones, no > > new ones will happen. > > No matter you hate them or not, they are useful: No argument there. > Unlike in sched, tracepoints are welcome in networking: > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/log/include/trace/events/tcp.h They are also absolutely disallowed in the vfs.. > I don't want to change your mind, just want to show the facts. The problem with tracepoints is that they can become ABI and you cannot change them without breaking tools. This is a crap situation and I'm fed up with it.