Dual processor

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Darryl Kerkeslager - 22 Jan 2006 19:57 GMT

Not that I'm going to go out and buy a new motherboard, but, will a dual
processor PC run a huge report query and still allow a user to use other
programs while the query is running?

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Darryl Kerkeslager

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Tom van Stiphout - 23 Jan 2006 02:06 GMT

Yes.
But so does a single CPU.
That is, if the software manufacturer used best practices.

Windows uses "cooperative multi-tasking", which means that if you
really want to, you can grab the CPU (or (perhaps even more likely)
some other resource) and hang on to it 'forever' and get your thing
done in the shortest amount of time while disallowing other apps to
run normally.
It also means that well-behaved applications have every opportunity to
yield the use of resources to other players, and if the market place
paid more attention to these traits, then they would dominate the
desktop by now.

In my experience dual-CPU doesn't solve a lot of problems.

-Tom.

>Not that I'm going to go out and buy a new motherboard, but, will a dual
>processor PC run a huge report query and still allow a user to use other
>programs while the query is running?

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Steve Jorgensen - 23 Jan 2006 08:49 GMT

> Yes.
> But so does a single CPU.
> That is, if the software manufacturer used best practices.

Windows 95 added preemptive multi-tasking capability, and software has
not been required to be written a special way to share CPU time with
other applications since that time. In Windows NT and 2000 and above,
it is not even possible for an application to hog 100% of CPU time on
purpose.

> Windows uses "cooperative multi-tasking", which means that if you
> really want to, you can grab the CPU (or (perhaps even more likely)
> some other resource) and hang on to it 'forever' and get your thing
> done in the shortest amount of time while disallowing other apps to
> run normally.

Not since Windows 3.1.

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Tom van Stiphout - 23 Jan 2006 13:34 GMT

The way you write it, it seems the OP couldn't have seen what he did:
he runs a large report query and during that time cannot use his
computer for other tasks.

Looks like even today the OS needs the applications' cooperation to
remain responsive, regardless of the multi-tasking method.

-Tom.

>> Yes.
>> But so does a single CPU.
[quoted text clipped - 13 lines]
>
>Not since Windows 3.1.

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david epsom dot com dot au - 23 Jan 2006 22:54 GMT

User applications are normally written to take
high priority. If you have two user applications
running, they will each run half as fast, which
is a massive slowdown.

System processes are normally written to take
low priority, which works well for small user
applications, but is poor when doing massive
long-running foreground processes.

>>> That is, if the software manufacturer used best practices.

It is not best practice to write foreground applications with low priority.

In a perfect world, computers would be infinitely powerful and infinitely
adaptive.

In the real world, software designers have to compromise between conflicting
requirements.

(david)

> The way you write it, it seems the OP couldn't have seen what he did:
> he runs a large report query and during that time cannot use his
[quoted text clipped - 22 lines]
>>
>>Not since Windows 3.1.

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Darryl Kerkeslager - 24 Jan 2006 00:31 GMT

> The way you write it, it seems the OP couldn't have seen what he did:
> he runs a large report query and during that time cannot use his
> computer for other tasks.

"Cannot use" may not be what I meant to write - more like the slowdown is
abominable. This is mainly an issue with the work computer, XPPro,
switching between the query running (v. large and run over WAN) and Word,
Outlook, Excel.

Perhaps the issue is memory or the network. When I run the report over my
LAN at home, it runs so fast that I don't notice any problem.

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Darryl Kerkeslager

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david epsom dot com dot au - 23 Jan 2006 22:59 GMT

Please try it and tell us :~)

If you have one processor doing joins, and
the other handling disk access, and you have
used up all of your memory, then I guess
any other programs are still going to run
slow.

So if Access/Jet is well optimised for dual
processors, then other programs will be slow.

But if Access/Jet is deliberately throttled
to one processor, then other programs may
run well!

(david)

> Not that I'm going to go out and buy a new motherboard, but, will a dual
> processor PC run a huge report query and still allow a user to use other
> programs while the query is running?

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Darryl Kerkeslager - 24 Jan 2006 00:32 GMT

> Please try it and tell us :~)

Just put the new motherboard in the mail to me, please ...

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Darryl Kerkeslager

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Darryl Kerkeslager - 24 Jan 2006 00:34 GMT

> So if Access/Jet is well optimised for dual
> processors, then other programs will be slow.
>
> But if Access/Jet is deliberately throttled
> to one processor, then other programs may
> run well!

All programs are MS Office programs, so I guess that all (other than
Outlook) are built similarly.

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Darryl Kerkeslager

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