Re: 2 60MHz SuperSPARCs or 1 100MHz HyperSPARC? (SUMMARY)

From: John DiMarco (
Date: Wed Dec 14 1994 - 16:19:23 CST (Obi Thomas) writes:

>In article <>, I asked:

>> I have an old SS10/30. Time to upgrade. Which path would you advise, and
>> why: an MP upgrade to 2 60MHz SuperSPARCs, or stay uniprocessor and
>> upgrade to a 100MHz HyperSPARC?


>There were basically three types of answer:

>(1) In a heavily loaded GUI environment like a development system, you get
>better response if you have multiple processors, since the various
>processors like editor, window manager, etc., are not all competing for
>CPU. Further, the 60MHz TI SuperSPARC is only a little slower than a
>100MHz HyperSPARC. Recommend: 2 TI SuperSPARCs.

On a single-user development machine, typically only one client is active at
a time (the one being typed into), and it spends most of its time waiting for
the user's next keystroke. In an X environment, if an output-intensive client
is active (eg. mpeg_play), the X server and the client can indeed compete for
a single CPU, so a dual-CPU system will provide some benefit, but this is
rarely the case on a single-user machine being used for software development.

>(2) The HyperSPARC is a more modern architecture

Not true. Viking (SuperSPARC) and Pinnacle (HyperSPARC) were developed at
roughly the same time and at roughly the same technology level. If anything,
Viking is more technologically aggressive than Pinnacle.

>an MP solution does not scale as well as a high-clockspeed solution. I/O
>to and from devices will show no improvement at all.

I/O differences between the two options are negligible. It is most certainly
not the case that a system with a single processor at a higher clock rate has
some sort of automatic I/O advantage over an MP system. On the contrary, a
multithreaded kernel (eg. as in Solaris 2.x) can occasionally take advantage
of multiple CPUs to parallelize I/O operations.



John DiMarco <>                        Office: EA201B
Computing Disciplines Facility Systems Manager            Phone: 416-978-1928
University of Toronto                                     Fax:   416-978-1931

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