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From Tommaso Teofili <tommaso.teof...@gmail.com>
Subject Re: Lock and Barrier Synchronization
Date Fri, 24 Jun 2011 06:12:34 GMT
2011/6/24 Edward J. Yoon <edwardyoon@apache.org>

> Yes. I thought like that too but, I need more time to test.
>
> I'm re-scheduling it to 0.4 version.
>

Right, and we need to get rid of Thread.sleep() as it theoretically doesn't
guarantee anything about lock release.
Tommaso


>
> On Wed, Jun 22, 2011 at 6:12 PM, ChiaHung Lin <chl501@nuk.edu.tw> wrote:
> > From the code I observed, it seems that znodes created are consisted of
> peer names only (in the form of `host:port'). Therefore, processes at
> different superstep share the flat namespace. During iteration of each
> supersteps, the newer superstep process can not be distinguished from the
> older one, resulting in process hanging. Adding superstep value to created
> znode and filtering out znode of next superstep might solve the problem.
> >
> > But I haven't tested the code, so I may be wrong because of
> misunderstanding.
> >
> > -----Original message-----
> > From:Edward J. Yoon <edwardyoon@apache.org>
> > To:hama-dev@incubator.apache.org
> > Date:Tue, 21 Jun 2011 17:20:21 +0900
> > Subject:Re: Lock and Barrier Synchronization
> >
> > Especially, this can be problematic when locking a large number of
> BSPPeers.
> >
> > On Tue, Jun 21, 2011 at 5:13 PM, Edward J. Yoon <edwardyoon@apache.org>
> wrote:
> >> Hi all,
> >>
> >> Recently I'm looking at HAMA-387.
> >>
> >> There's some problem related with lock and barrier synchronization.
> >> The problem is as soon as last one of lock files deleted (before
> >> completely escape from while loop at leaveBarrier method), others
> >> begin to create their lock file. So, sometimes, it causes hang.
> >>
> >> My temporary solution is 'Thread.sleep(200);'. Good but not perfect.
> >> If zk.getChildren() response is slower than 200 milliseconds, process
> >> will be hanged.
> >>
> >> Is there any other idea?
> >>
> >> Thanks.
> >> --
> >> Best Regards, Edward J. Yoon
> >> @eddieyoon
> >>
> >
> >
> >
> > --
> > Best Regards, Edward J. Yoon
> > @eddieyoon
> >
> >
> > --
> > ChiaHung Lin
> > Department of Information Management
> > National University of Kaohsiung
> > Taiwan
> >
>
>
>
> --
> Best Regards, Edward J. Yoon
> @eddieyoon
>

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