Excess threads reporting on deadlock

[Keith McGuigan]

Just did now.

On Feb 2, 2011, at 3:22 PM, Dmytro Sheyko wrote:

> Keith,
>
> Have you tried to re-open the bug? I can't see changes in its status.
>
> Thanks,
> Dmytro
>
> CC: david.holmes at Sun.COM; serviceability-dev at openjdk.java.net
> From: keith.mcguigan at oracle.com
> To: dmytro_sheyko at hotmail.com
> Subject: Re: Excess threads reporting on deadlock
> Date: Mon, 31 Jan 2011 11:09:13 -0500
>
>
> You'll have to excuse me while I struggle to remember the details of  
> this one, but I believe that the deadlock detection code in the VM  
> only detects the existence of a deadlock when it happens, but it  
> doesn't know which threads are a part of it.   Any thread that is  
> currently blocked is a potential contributor to the deadlock, so the  
> VM prints out information about all the blocked threads so that the  
> developer can determine where the deadlock is and how to fix it.      
> I could be wrong about this -- it's been a while since I looked at it.
>
> Again, IMO, this ought to be fine, but I understand if you've got  
> lots of blocked threads than you might have a lot of extra data to  
> slog through.  I can re-open the bug if you like (perhaps as an  
> RFE?), but it's not likely to be a high enough priority to be  
> "fixed" anytime in the near future.  Unless someone wants to  
> investigate the code to find and suggest a fix (hint,  hint).
>
> --
> - Keith
>
> On Jan 31, 2011, at 10:20 AM, Dmytro Sheyko wrote:
>
> Hi Keith,
>
> Thank you for information about this bug.
> May I convince you of the need for fixing it?
>
> "The more the better" approach does not go well here.
> Doesn't it make sense to report all threads (including even not  
> blocked ones)?
> Analyzing deadlock it's important to know threads that form cycle.  
> The problem is almost always in code that these threads execute.
> Other threads just hinder analysis. But if I need them I can use  
> other API that gives me the list of all threads.
>
> However, existing behavior does not even follow "the more the  
> better" approach properly.
> Sometimes the deadlock is reported as (A, B, C), sometimes as (B, C,  
> D) and as (B, С), but never as (A, B, C, D).
> The set of threads that are reported is not clearly defined.
>
> Thanks,
> Dmytro
>
> CC: david.holmes at sun.com; serviceability-dev at openjdk.java.net
> From: keith.mcguigan at oracle.com
> To: dmytro_sheyko at hotmail.com
> Subject: Re: Excess threads reporting on deadlock
> Date: Mon, 31 Jan 2011 07:57:00 -0500
>
>
> Hi Dmytro -
>
> This bug was marked 'closed' because the behavior noted is  
> intentional and we do not believe it should be changed.  When an  
> error situation such as a deadlock occurs we want the developer to  
> have as much information as possible to help resolve the issue.
>
> --
> - Keith
>
> On Jan 31, 2011, at 4:52 AM, Dmytro Sheyko wrote:
>
> Corrections: I am about this one:
> http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6850341
>
> From: dmytro_sheyko at hotmail.com
> To: david.holmes at sun.com
> Subject: RE: Excess threads reporting on deadlock
> Date: Mon, 31 Jan 2011 16:48:55 +0700
> CC: serviceability-dev at openjdk.java.net
>
> Hi,
>
> I just noticed that the bug report is closed. Can I know why?
>
> Thanks,
> Dmytro
>
> > Date: Fri, 5 Jun 2009 03:41:17 +1000
> > From: David.Holmes at Sun.COM
> > Subject: Re: Excess threads reporting on deadlock
> > To: dmytro_sheyko at hotmail.com
> > CC: serviceability-dev at openjdk.java.net
> >
> > Hi Dmytro,
> >
> > Thanks for submitting these. I just wanted to say that a lack of  
> immediate
> > response on the mailing lists does not mean noone is, or will,  
> look at
> > these, but it may be a while before people have the cycles to do so.
> > Certainly this week is not a good week :)
> >
> > David Holmes (from JavaOne)
> >
> > Dmytro Sheyko wrote:
> > > Hi,
> > >
> > > Another one patch about deadlock detection:
> > >
> > > Excess threads reporting on deadlock
> > > https://bugs.openjdk.java.net/show_bug.cgi?id=100065
> > >
> > > --
> > > Dmytro Sheyko
> > >  
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> >
>
>
>
>

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