🚀 go-pugleaf

William Park <opengeometry@yahoo.ca> wrote:
>In comp.os.linux.hardware Floyd Davidson <floyd@ptialaska.net> wrote:
>> warren22432@yahoo.com (warr) wrote:
>>>"Scud" <arahmati(NOSPAM)@ihug.com.au> wrote in message news:<av5qtf$tcf$1@lust.ihug.co.nz>...
>>>> hmm well when i researched the dual vs. single CPU option there wasnt must
>>>> to gain from dual CPU for what i wanted to do so single seemed the way to go
>>>> unless you plan on using software writtne to utilise the dual advantage...
>>>
>>>this is true. and if the software is only written for single CPU, your
>>>dual CPU system may be even slower than Single CPU system.
>> 
>> How do you figure that?
>> 
>> A single cpu system might be faster *if* there is only one
>> process running most of the time.  On the other hand, if there
>> are 2 or more processes running a dual cpu system is going to be
>> faster.  On my box the X server is always running, plus whatever
>> else I'm doing.  Hence there is *never* a time when a single cpu
>> would be as fast as a dual cpu system for my typical usage.
>
>Obviously, you don't do much harddisk trashing.  For CPU consideration

Oh, really...  I've got a SCSI RAID5 array on my duallie.  However,
nothing you say here addresses the comment that I was responding to,
which stated that a dual cpu system may be slower than a single cpu
system.  What is your point?

>only, dual can run 2 processes, so it's more responsive, both in theory
>and in practice.  If you are doing lots of IDE I/O, then your computer
>will crawl no matter what.

That depends on what kind of IO.  You might have noticed that
Linux does disk caching...  which has quite an effect on that.

It also depends on the disks too.  I've got an older box here
with SCSI disks that are half as fast as the newer IDE disk on it.
Most disk thrashing is the same from either disk though, because
it actually is RAM cache thrashing.

Are you saying that box would run faster if I removed the IDE drive
and one cpu???    I  don't  think  so...

>  So, it makes more sense to go with
>single-CPU and spend some money on SCSI.

Which one should be a higher priority depends on what type of
load the system has.  If it works as a file server, most certainly
a faster disk subsystem is going to be more significant.  It if is
compute bound or does a great deal of repetitive reading of the
same disk sectors, that won't make much difference.

Regardless, none of that addresses the question I was responding
to or the comments leading up to it which suggests that unless
the software is written specifically with multiple cpu's in mind
it won't benefit from a dual cpu system.  That simply isn't true
and the disk subsystem is not significant.

>Also, dual-motherboard is hard to come by and is expensive.  The usual

Hard to come by?  I don't think so.  And well, garsh... SCSI
disks are not expensive???

>argument that you only have to have one RAM, one case/power supply, one
>video/network card, etc is valid.  So, the OP has to do his own math...

Of course he will have to deal with his own circumstances.  I'm
not sure what your point about "one RAM, one case/power
supply..." is or what makes it valid, either.

-- 
Floyd L. Davidson         <http://www.ptialaska.net/~floyd>
Ukpeagvik (Barrow, Alaska)                 floyd@barrow.com