Re: [Gems-users] ordering in buffers

[Nauman Rafique <nrafique@xxxxxxxxxx>]

I figured why this break is there. So please ignore.
Thanks.
-- 
Nauman


Quoting Nauman Rafique <nrafique@xxxxxxxxxx>:

> I think my problem is this statement inserted in Directory_Wakeup.C, a file
> generated by SLICC.
> -------------------------------------------------------------
>     break;  // If we got this far, we have nothing left todo
> -------------------------------------------------------------
> 
> This is being added towards the end in the while loop which is taking
> requests
> out of the buffers. If my buffer has multiple requests, they would not be
> taken
> out, causing a deadlock.
> Should I take this break statement out or it is serving a purpose here. 
> I do not want to mess up with/debug the coherence protocol again :)
> 
> Thanks.
> -- 
> Nauman
> 
> 
> Quoting Mike Marty <mikem@xxxxxxxxxxx>:
> 
> > To add to this, if the RANDOMIZATION flag in ruby/config/tester.defaults
> > is set to "true" (which is the default), then 100-cycle delays will be
> > randomly added to messages in unordered buffers to encourage race
> > conditions and protocol failures to occur for testing purposes.
> > 
> > --Mike
> > 
> > >
> > > Nauman,
> > >
> > > It depends on the cache coherence protocol whether messages on certain
> > > virtual channels can get out-of-order.  When a buffer is unordered, the
> > > tester will allow messages to bypass eachother on a point-to-point link.
> > > For instance, some protocols will deadlock if a GET request moves ahead
> of
> > > a PUT request to the directory, which could happen if you set the
> requests
> > > queue to be unordered.
> > >
> > > Look at the trace closer.  It is not always easy to tell what event
> causes
> > > the deadlock, but through some persistence, you should find it.
> > >
> > > Brad
> > >
> > >
> > >
> > > On Wed, 30 Mar 2005, Nauman Rafique wrote:
> > >
> > > > I am wondering how much difference does it make if we set some of the
> > buffers to
> > > > be unordered?
> > > > I have set a couple of buffers to be unordered, and Tester is
> reporting
> > a
> > > > deadlock. I am not really sure why deadlock occurs because from the
> > trace,
> > > > everything looks fine. And I am simulating with only 1 processor.
> > > > If I set the buffer to be ordered, it works fine.
> > > >
> > > > Thanks.
> > > > --
> > > > Nauman
> > > >
> > > >
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