JavaMemoryModel: Is reordering of dependent reads on Alpha actually possible?

From: Jeremy Manson (jmanson@cs.umd.edu)
Date: Tue Feb 29 2000 - 15:30:34 EST


>
> > We have written a short program to try to duplicate such a result, and
> > run it on an AlphaServer 2100/A (this runs 4 21064A processors). This
> > program is available at http://www.cs.umd.edu/users/jmanson/java.html.
> >
> > We tried it with both dependent and independent reads, and we have seen
> > no results which would indicate that this read of a stale cache value /
> > instruction reordering is occurring. Does anyone know of or have access
> > to a SMP Alpha that might encounter these difficulties?
>
> The reordering does happen with 21164 and 21264 Alphas.

Hello,

I thought it might be of interest to the list to mention that the
reordering did not happen on the 21164 and 21264 Alphas when we adjusted
to program to take into consideration dependent reads. The matter is
still under consideration...

A new program to test dependent reads is at the old URL,
http://www.cs.umd.edu/~jmanson/java.html

                                        Jeremy
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