RE: Dual or Single CPU?

["Colin J. Raven" <cjraven ddf-lab com>]

I never thought that was the case, but the clarification you provided below
is invaluable.
>Many people are under the false impression that 2 500MHz CPUs = 1 1GHz CPU.
>Wrong, wrong, wrong.

Trying to translate this into designing a box whose ultimate daily use is
still unclear is...shall we say..."somewhat challenging" :-)
My own (admittedly amateur) take on this is; "When in doubt, throw massive
resources at the problem" That's not flame bait, it's just a personal
opinion that (so far) usually works.

Now, can anyone say for certain what core Linux processes (VMWare comes to
mind, but that's specific to my own application) such as postfix, apache,
procmail...and son can effectively use a dual cpu box?

What are the complexities of getting a dual cpu setup running in a stable
happy manner?


Regards to all,
-Colin
>
>If you have a single CPU, the OS (If it supports it) generally gives each
>process a few processor ticks in succession.  Certain things have higher
>priorities so get more ticks per go-around, or get more turns on the ride.
>
>When a process is running, tho, it gets nearly the full computing
>horsepower
>available.
>
>If you have 2 processors, and the OS supports it, you can see a speed
>increase in certain situations.
>
>1)  If the OS load balances the CPU's, then if you ran the same number of
>processes as on your single CPU system, each one will get 2x as many rides
>in the same time.  If these two CPUs are the same speed as your single CPU,
>the speed boost is approximately 25-50%
>
>2)  If the program is designed to do parallel processing across multiple
>CPU's and the CPU is the same speed as your 1 processor, then you
>can see as
>much as a 90% speed increase.
>
>
>> -----Original Message-----
>> From:	Colin J. Raven [SMTP:cjraven ddf-lab com]
>> Sent:	Friday, October 27, 2000 11:52 AM
>> To:	redhat-install-list redhat com
>> Subject:	RE: Dual or Single CPU?
>>
>> OK, let me take a moment to clarify the "why" here, just so that
>you folks
>> know; "where I'm coming from" on this project. It's not a
>hobbyist's dream
>> (well, I guess it is in a way) but has more serious overtones.......
>>
>> This is a "proof of concept" exercise that I have undertaken on behalf of
>> my
>> company. I gave up smoking, so I decided to buy myself a present
>using the
>> equivalent amount 'o cash that I would have seen go up in smoke
>and do the
>> project as a personal learning exercise.
>>
>> I too wondered about the single/dual cpu question. In truth I always
>> wanted
>> to see what a dual cpu  fire breathing monster would feel like...(yeah, I
>> know...F.A.S.T) so in ths case it was a real dilemma believe me. It was
>> exactly as you wrote...one top 'o the line cpu...or two? I
>punked out when
>> the dollars climbed, and although I *could* have squeezed just a little
>> more
>> into this project, I was shellshocked enough to call it quits.
>Essentially
>> I
>> figured that I probably needed more memory as opposed to CPU
>cycles, since
>> this machine will probably never see a graphics program, and I
>am unlikely
>> to be cruching 1 million record database queries.
>>
>> So, I'm interested in this thread too. It's not too late to change to a
>> dual
>> cpu config if there is a consensus that *that* setup would deliver a
>> "better" result. (The VMWare/Win side will be doing significant Access
>> small
>> database work, so maybe there really is a clock cycle issue here, but I
>> thought that a Xeon chip would have the architecture [stamina? "Right
>> Stuff"?] to do the job. The darned machine will take up to 2GB of RAM as
>> well as a second CPU, so my options going forward are fairly wide open I
>> think.
>>
>> This was just for clarification, that's all.
>>
>> Regards to all, and thanks for the many suggestions that have flowed this
>> way so far...and my guess is that we're far from finished yet.
>>
>> -Colin
>> --
>> Colin J. Raven
>>
>> >-----Original Message-----
>> >From: redhat-install-list-admin redhat com
>> >[mailto:redhat-install-list-admin redhat com]On Behalf Of Rob Toner
>> >Sent: Friday, October 27, 2000 11:14 AM
>> >To: redhat-install-list redhat com
>> >Subject: Re: Dual or Single CPU?
>> >
>> >
>> >"C. Bryan Young" wrote:
>> >
>> >> This is sort of related to Colin's earlier post -- regarding the
>> >specs for
>> >> his new workstation.  I'm just curious whether -- for the same
>> >price -- it
>> >> is better to get 1 top-of-the-line cpu (in his case a 933MHz
>Xeon) or 2
>> >> lesser cpus (say, PIII 800 MHz).
>> >>
>> >> I know this depends on intended application.  Let's say one wanted to
>> run
>> >> dual OS's using VMWare.  I would tend to think that dual
>cpu's would be
>> >> better, but don't know enough about smp -- especially in Linux -- to
>> know
>> >> for sure.
>> >>
>> >> Any thoughts?  I'm just curious -- want to learn more about smp in
>> Linux.
>> >>
>> >> --Bryan
>> >>
>> >> -----Original Message-----
>> >> From: Jeff Lane [mailto:jlane redhat com]
>> >> Sent: Friday, October 27, 2000 9:23 AM
>> >> To: redhat-install-list redhat com
>> >> Subject: RE: RedHat 7.0 and Matrox G400 compatibility
>> >>
>> >> On Fri, 27 Oct 2000, Colin J. Raven wrote:
>> >>
>> >> > Anyone from RedHat care to comment on this one?
>> >> > There's a $5500 workstation on hold until we can successfully
>> >resolve this
>> >> > issue.
>> >> > Regards,
>> >> > -Colin
>> >>
>> >> Hey... read my other posts... <grin>
>> >>
>> >> I have the Precision 420 here wiht the 32 MEg G400.  the original mga
>> >> driver didnt work too well with the card.  I was forced to use X
>> >> 3.3.6.  there is a new driver
>> >> http://www.matrox.com/mga/support/drivers/files/linux_03.cfm here!!
>> >>
>> >> I found it!!!
>> >>
>> >> from the matrox site:
>> >> This driver is based on the open source development being done within
>> the
>> >> XFree86 Project. The driver remains unmodified, with the exception of
>> the
>> >> display adapter initialization, which has been replaced with a closed
>> >> source Matrox library. This special library enables features such as
>> >> DualHead, TV out, and support for digital flat panel monitors.
>> >>
>> >> The readme included instructions for gettiung DRI and multihead
>> >working as
>> >> well.
>> >>
>> >> I feel much better now that i have found htat driver again.
>> >>
>> >> cheers
>> >>
>> >>  --
>> >> (-0-)  (-0-)  (-0-)  <-0->  (-0-)  (-0-)  (-0-)
>> >> Jeffrey D Lane
>> >> Geek, Star Wars Fanatic, and collector of
>> >> obselete technologies.
>> >>
>> >> 2600 Meridian Parkway   (919) 547-0012x168
>> >> Durham, NC 27713        (888) REDHAT1x168
>> >>
>> >> "I propose that every city have a telephone
>> >> number 119 -- for dyslexics> who have an
>> >> emergency." -George W. Bush
>> >> (-0-)  (-0-)  (-0-)  <-0->  (-0-)  (-0-)  (-0-)
>> >>
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>> >
>> >If you go with dual, lets say two 500 you get almost the same as
>> >one 1gig.  Of
>> >course the price is a little cheaper.  The main thing is you get
>> >smp.  VMWare
>> >you take a large hit on performance, but if you must, then go
>for it.  It
>> >really depends on the app that your running.  RH supports SMP but
>> >if the app
>> >doesn't then there isn't any gain (for that app).
>> >
>> >
>> >
>> >
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