From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:53816 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751680AbdECCrZ (ORCPT ); Tue, 2 May 2017 22:47:25 -0400 Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.20/8.16.0.20) with SMTP id v432hoML146465 for ; Tue, 2 May 2017 22:47:24 -0400 Received: from e12.ny.us.ibm.com (e12.ny.us.ibm.com [129.33.205.202]) by mx0a-001b2d01.pphosted.com with ESMTP id 2a765q90s8-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 02 May 2017 22:47:24 -0400 Received: from localhost by e12.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 2 May 2017 22:47:23 -0400 Date: Tue, 2 May 2017 19:47:19 -0700 From: "Paul E. McKenney" Subject: Re: [Q] Heisenbug and anti-heisenbug Reply-To: paulmck@linux.vnet.ibm.com References: <883b737a-0c32-dedc-daff-db556a6ec83a@gmail.com> <61b85306-48c8-d90d-b6a0-e56dbe1b75a3@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <61b85306-48c8-d90d-b6a0-e56dbe1b75a3@gmail.com> Message-Id: <20170503024719.GK3956@linux.vnet.ibm.com> Sender: perfbook-owner@vger.kernel.org List-ID: To: Akira Yokosawa Cc: perfbook@vger.kernel.org On Wed, May 03, 2017 at 09:23:11AM +0900, Akira Yokosawa wrote: > On 2017/05/03 09:09:37 +0900, Akira Yokosawa wrote: > > Hi Paul, > > > > While reviewing your recent update in "Hunting Heisenbugs" section, > > I found the analogy with particle physics didn't sit well with me. > > > > "Heisenbug" is defined as: > > > >> attempts to track down the heisenbug causes it to radically change > >> its symptoms or even disappear completely. > > > > "Anti-heisenbug" is introduced as: > > > >> Fortunately, particle physics is up to the task: Why not create > >> an anti-heisenbug to annihilate the heisenbug? > > > > At this point, "anti-heisenbug" seems to mean a patch that fixes > > the heisenbug. > > > > The use of anti-something in particle physics does not go along > > with this usage. > > > > For example, antiproton is an antiparticle of proton. > > antiproton has mostly the same property as proton, > > with the exception of electric charge and magnetic moment. > > Also, an antiproton and an antielectron (positron) can compose > > an antihydrogen atom. Well, I'm sure you know all about this. > > > > So, if you employ this line of reasoning, an anti-heisenbug should > > also be a bug with something opposite in nature. > > > > If a heisenbug is a bug which vanishes when it is being tracked down, > > an anti-heisenbug would be a bug which only emerges when it (or > > something else) is being tracked down. > > > > However, it is not obvious you can create an anti-heisenbug for > > a particular heisenbug so that when the two are combined, the symptoms > > of both bugs to "annihilate". > > > > So I'm wondering "What was Paul's intention in using the word 'annihilate'?". > > > > In Section "Add Delay", anti-heisenbug is used as: > > > >> Once you spot a bug involving a race condition, it is frequently > >> possible to create an anti-heisenbug by adding delay in this manner. > > > > This "anti-heisenbug" is not a bug, rather, it is a means to increase > > the possibility of a given heisenbug to appear. > > > > Oops, I sent this prematurely. > But you might be able to see my point here. > > This is not an important question, so please give it a look when you have > done with whatever issue you are working on. I freely admit that I am taking a fair amount of "poetic license" here. ;-) Thanx, Paul