From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 74705C3A5A8 for ; Wed, 4 Sep 2019 17:47:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4063622CEA for ; Wed, 4 Sep 2019 17:47:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="HLCgQx30" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731565AbfIDRrg (ORCPT ); Wed, 4 Sep 2019 13:47:36 -0400 Received: from merlin.infradead.org ([205.233.59.134]:37804 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730236AbfIDRrg (ORCPT ); Wed, 4 Sep 2019 13:47:36 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=s7U+WnWbc1hGktvptzKeOfYseeeg3nRJZ5+fdX9uzys=; b=HLCgQx30fbj3bDt5K0UFUQYmN aFtidFqbXsrutc8ApRSxRfYlvZiok4MBC+OeYVQ0D6gZGvOQxY2KSETfhfca49jarfXO/usT4t1Jp g92XShJHHBDYEmtDWo4qtjnr7vw/BoAZp9n7SH9XvA4jVx5cQ97qdh7cXVSD+20u5iX2JhBbS+1nf 7Mpx+ylWFAUn1s02mDl1djBgJtD8AYbVgtzCEwISxhP1SvOSeDv9JSYN7+f15gNa2Q1xONov5qmXq g8ob/t19aYpa3AIYBktVYJzxCIg/1T+Ke0jewcFsY1DJIlGyOZOEOTEdr6y5g7lipKFwGLSXHDcTb 1ePchfG2w==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92 #3 (Red Hat Linux)) id 1i5ZN7-00018k-HY; Wed, 04 Sep 2019 17:47:09 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 8279C30116F; Wed, 4 Sep 2019 19:46:30 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 2A14C29D8ACE6; Wed, 4 Sep 2019 19:47:07 +0200 (CEST) Date: Wed, 4 Sep 2019 19:47:07 +0200 From: Peter Zijlstra To: Alexei Starovoitov Cc: Joel Fernandes , Qais Yousef , Valentin Schneider , Radim =?utf-8?B?S3LEjW3DocWZ?= , LKML , Ingo Molnar , Thomas Gleixner , Borislav Petkov , Dave Hansen , Steven Rostedt , "H. Peter Anvin" , Andy Lutomirski , Jirka =?iso-8859-1?Q?Hladk=FD?= , =?utf-8?B?SmnFmcOtIFZvesOhcg==?= , X86 ML Subject: Re: [PATCH 2/2] sched/debug: add sched_update_nr_running tracepoint Message-ID: <20190904174707.GV2332@hirez.programming.kicks-ass.net> References: <20190903154340.860299-1-rkrcmar@redhat.com> <20190903154340.860299-3-rkrcmar@redhat.com> <20190904042310.GA159235@google.com> <20190904104332.ogsjtbtuadhsglxh@e107158-lin.cambridge.arm.com> <20190904130628.GE144846@google.com> <20190904154000.GJ240514@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 04, 2019 at 08:51:21AM -0700, Alexei Starovoitov wrote: > Anything in tracing can be deleted. > Tracing is about debugging and introspection. > When underlying kernel code changes the introspection points change as well. Right; except when it breaks widely used tools; like say powertop. Been there, done that.