Re: [Q] Heisenbug and anti-heisenbug

["Paul E. McKenney" <paulmck@linux.vnet.ibm.com>]

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