[Info-vax] BOINC for VMS

[David Froble]

Johnny Billquist wrote:
> On 2012-04-03 19.10, David Froble wrote:
> 
> [...]
> 
>> Myself, (which probably doesn't mean much), I feel that the OoO concept
>> in Alpha and Power provides a method to get faster processing out of a
>> set of instructions, if, IF, you can coordinate it well enough. How to
>> do this? Simple, one word, "money". Takes lots of smart people trying
>> different ideas, adopting those that work, and setting aside those that
>> don't work, "today". DEC didn't, or couldn't, continue to fund Alpha. So
>> far I haven't heard that IBM has taken that route.
>>
>> Process shrinks and tons of cache have made the itanic much faster than
>> the Alphas. That, and some small inter-core communication improvements
>> are all Intel has been able to manage.
> 
> I basically agree with all you write. Signals speeds and distances are 
> the limiting factors today, and signal speed is not going to change 
> much. Size are also getting close to their lower limits, which leaves 
> more clever execution.
> 
> I'm curious though, is really the Itanium that much faster than the Alpha?
> 
>     Johnny

 From my limited exposure, I believe it is.

We have a large number of customers who have moved from PDP-11 to VAX to Alpha, and now 
Itanium.  But the CPU is not the only changes over the years.  Alphas with plenty of 
memory, and the cacheing that was implemented in somewhere around VMS V7.3 were very 
capable.  Some of that was due to the cacheing of data.  If we would disable the data 
cache, the systems would become slow.  The difference was not small, it was major.  With a 
significant part of the database in cache, especially the keys, data access was greatly 
enhanced.

So, was the Alphas faster than the VAXs?  The cache and larger memory was a large part of 
it, but yes, the later Alphas were faster.  We did some CPU intensive benchmarks to get an 
idea how much faster, but I cannot remember the numbers, that was 12-13 years ago.

The itaniums that we've put in at the customer sites all have lots of memory.  Even more 
of the database ends up sitting in memory.  Regardless, we can measure greater CPU 
performance, in the limited testing we've done.  I'm not the one to answer some of the 
details, but, I believe EV7 did some things that were and are still better than the itanic 
can do, but that was the inter-CPU communications in a multi-processor (like 32 CPUs) 
system.  But even there, it isn't the CPU architecture, it's the other stuff on the chip, 
which probably could be done on an itanium chip.

I do remember Bill Todd putting the question to one of the Alpha chip engineers, "what is 
more important for speed, architecture design or process (die size)", and the immediate 
response was "process".  So even back then, it was basically stated that process shrinks 
would do more for speed than architecture.  So what was EV7?  110 nano or even larger? 
What is the current die size for the itanic, and then there is that hugh on-chip cache ...

So all things being equal, perhaps Alpha would be better than itanium, but, all things are 
not equal.  It's a moot point at this point in time.  There are not and most likely will 
not be any 35 nanometer Alphas.