[gentoo-user] hardware advice for dual-processor set-up on gentoo

[gentoo-user] hardware advice for dual-processor set-up on gentoo

[Denis]

Folks,

I am currently running Gentoo on a dual-processor machine that has 2
Intel Xeons with hyperthreading on a Tyan board, with 2GB of RDRAM. 
Some 3 years ago when I bought this machine, it was a marvel, and it
still is a solid computational workhorse for me, doing things like
Monte Carlo and Finite Element calculations.  Because of
hyperthreading, there are 4 logical processors, which gives me a good
multi-tasking ability.  I can run 3 or 4 Monte Carlo tasks at the same
time and not get any noticeable slow-down compared to running only one
Monte Carlo task.  That has been indispensable in my productivity.

Now, I am about to purchase a new machine, but I'd like to solicit
some advice first, so I can get the most bang for the buck.  The main
thing is, I still need to have those 4 logical processors to maintain
my productivity.  So that gives me two choices:

- 2 64-bit Irwindale Xeons (EM64T) with Hyperthreading, 2MB L2 Cache,
800 MHZ FSB, somewhere in 3.4-3.8 GHz range

- 2 64-bit AMD Dual-Core Opterons somewhere in the 265-275 range

With my need for parallel execution of several single-thread Monte
Carlo and Finite Element tasks, what would be the pros and cons in
considering the Xeons and Opterons?

I looked at several benchmarks, and the Opterons seem to be leading
the way significantly in pretty much every category except things like
Matrix multiplications (because of vectoring?)...  Is that the general
impression of folks with experience on these systems running Linux?

What would be some issues and software limitations for me in trying to
get the AMD Opterons running on Gentoo?  And would I use an x86
platform or an AMD64 platform?

Thanks!
Denis

-- 
gentoo-user@gentoo.org mailing list

Re: [gentoo-user] hardware advice for dual-processor set-up on gentoo

[Mike Williams]

On Monday 12 September 2005 21:40, Denis wrote:
> With my need for parallel execution of several single-thread Monte
> Carlo and Finite Element tasks, what would be the pros and cons in
> considering the Xeons and Opterons?

Opterons everytime.
Under certain circumstances HT can make the CPU *slower*, and at best only 
adds around a 20% performance boost.
A dual core CPU *is* two CPUs, with single digit % performance drop over 2 
full CPUs.

> What would be some issues and software limitations for me in trying to
> get the AMD Opterons running on Gentoo?  And would I use an x86
> platform or an AMD64 platform?

Issues? Almost exactly nil.
AMD64 support is excellent, if a little smaller and perhaps the tiniest bit 
behind, the x86 profile.

-- 
Mike Williams

-- 
gentoo-user@gentoo.org mailing list

Re: [gentoo-user] hardware advice for dual-processor set-up on gentoo

[John Jolet]

On Monday 12 September 2005 15:40, Denis wrote:
> Folks,
>
> I am currently running Gentoo on a dual-processor machine that has 2
> Intel Xeons with hyperthreading on a Tyan board, with 2GB of RDRAM.
> Some 3 years ago when I bought this machine, it was a marvel, and it
> still is a solid computational workhorse for me, doing things like
> Monte Carlo and Finite Element calculations.  Because of
> hyperthreading, there are 4 logical processors, which gives me a good
> multi-tasking ability.  I can run 3 or 4 Monte Carlo tasks at the same
> time and not get any noticeable slow-down compared to running only one
> Monte Carlo task.  That has been indispensable in my productivity.
>
> Now, I am about to purchase a new machine, but I'd like to solicit
> some advice first, so I can get the most bang for the buck.  The main
> thing is, I still need to have those 4 logical processors to maintain
> my productivity.  So that gives me two choices:
>
> - 2 64-bit Irwindale Xeons (EM64T) with Hyperthreading, 2MB L2 Cache,
> 800 MHZ FSB, somewhere in 3.4-3.8 GHz range
>
> - 2 64-bit AMD Dual-Core Opterons somewhere in the 265-275 range
>
> With my need for parallel execution of several single-thread Monte
> Carlo and Finite Element tasks, what would be the pros and cons in
> considering the Xeons and Opterons?
>
> I looked at several benchmarks, and the Opterons seem to be leading
> the way significantly in pretty much every category except things like
> Matrix multiplications (because of vectoring?)...  Is that the general
> impression of folks with experience on these systems running Linux?
>
> What would be some issues and software limitations for me in trying to
> get the AMD Opterons running on Gentoo?  And would I use an x86
> platform or an AMD64 platform?
>
> Thanks!
> Denis
I don't know the benchmarks, but I DO know that I got a 64-bit gentoo system 
running on a dual-core athlon 4400.  It's a single-dual-core cpu, using a 
Tyan Tomkat k8e board (only one cpu slot on the board).  There were no 
problems or gotchas I could tell.  It's got 4 gigs of ram and screams (at 
least on kernel compiles and such....haven't benchmarked mysql on it yet).
-- 
John Jolet
Your On-Demand IT Department
512-762-0729
www.jolet.net
john@jolet.net
-- 
gentoo-user@gentoo.org mailing list

Re: [gentoo-user] hardware advice for dual-processor set-up on gentoo

[Denis]

I was leaning toward the Opterons myself.

While we're on the topic of hardware, has anyone here used Tyan S2895
Thunder K8WE?  I understand it's an NVIDIA-based high-end board that
supports dual Opterons.  I've always liked Tyan's products, as well as
NVIDIA's, so I would be happy with such a choice...  But I am curious
to hear about people's experiences with or what they heard (good and
bad) about this particular board...

-- 
gentoo-user@gentoo.org mailing list

Re: [gentoo-user] hardware advice for dual-processor set-up on gentoo

[Bob Sanders]

On Mon, 12 Sep 2005 15:40:24 -0500
Denis <denis.che@gmail.com> wrote:



> With my need for parallel execution of several single-thread Monte
> Carlo and Finite Element tasks, what would be the pros and cons in
> considering the Xeons and Opterons?
> i

Xeons - massive memory bandwidth.  Really can't be beat for this, at the
		moment.  Very useful in specific cases, mostly involving video.
		Very costly in power consumption and heat production.
		Intel's compiler fairly cheap - approx. $600.  Free for non-commerical
		home use.

Opterons - more instructions issues per clock.  Held back by memory bandwidth.
		Dual core very efficient for multi-threaded apps.  Memory bandwidth issues
		won't be resolved until Jan/Feb when the new socket gets released and
		HyperTransport 3 with DDR2 is introduced.  But stable platform will occur
		around Summer 2006.  PathScale compiler a bit expensive - $900, but
		makes any AMD scream.  All SpecFP/INT benchmarks are done with
		the PathScale compiler.  BTW - The PathScale compiler will optimize
		Xeons as well.  Perhaps not as nice as Intel's compiler.

> What would be some issues and software limitations for me in trying to
> get the AMD Opterons running on Gentoo?  And would I use an x86
> platform or an AMD64 platform?
>

Typing this on one now.  I have been running Gentoo on a couple of 2P Opteron
systems for a couple of years now.  No real issues - sometimes an app won't compile.
The early K8W motherboard I have has come bug in it or the memory on one cpu has 
an issue, but it has a workarounds.  I've had it up to a load average of 70, run it
out of virtual memory, and no crashing. 

The other system is mainly used as an NFS file server, running Gentoo, loading distributions
for testing onto other systems.

Bob
-  
-- 
gentoo-user@gentoo.org mailing list

Re: [gentoo-user] hardware advice for dual-processor set-up on gentoo

[Denis]

Bob, 

Thanks for that detailed write-up.  I don't pretend to have any
understanding of the architecture of the new dual-core Opterons, but I
did want to clarify a couple things...

I was under the impression that the Opterons didn't have the same type
of a NorthBridge bottleneck that Intel processors experience and were
thus quite a bit more efficient in the way they integrate with RAM and
themselves!...  In fact, from reading the numbers posted on the AMD
website comparing FSB and memory bandwidth, the numbers for the
Opteron were much superior to those for Intel.  Reading what you wrote
would make me think that the numbers AMD published were some kind of a
marketing ploy??

The numbers I am referring to are in this PDF:
http://multicore2.amd.com/Products/CompetitiveComparisons/2P_Server_Comparison.pdf

Also, I read on more than one occasion that the DDR2-400 and DDR2-533
suffer from latency issues and perform more sluggishly than their DDR1
counterparts as of right now......

I mean, out of most benchmarks I've read, it looked like an Opteron
comes out on top compared to the Irwindale Xeons (even with their 2MB
L2 cache) including floating-point arithmetic, only with the exception
of matrix multiplication...  Also, it appears that the dual-core
Opterons have true multithreading as opposed to Intel's seemingly
superficial Hyperthreading?

I've been using Intel-only products so far in my computer experiences,
and this is the first time I am considering buying a non-Intel system,
so I want to make sure I understand enough about both processors to
make an educated decision.

You mentioned compilers...  Do you HAVE to use those instead of the
standard GCC stuff?  I've never used anything but GCC before for
compiling things.

Thanks!

-- 
gentoo-user@gentoo.org mailing list

Re: [gentoo-user] hardware advice for dual-processor set-up on gentoo

[Denis]

Ok, I felt compelled to find more info on the issue that Bob raised
with the memory bandwidth limitation on the Opterons, and here is an
excerpt from an article on anandtech.com on this issue:

"The one limitation that both AMD and Intel have is bandwidth.  In
order to maintain compatibility with present day Socket-940 and
Socket-939 motherboards, AMD could not increase the pincount of their
dual core processors.  The benefit is that AMD's dual core CPUs will
work in almost all Socket-940 and Socket-939 motherboards (more on
this later), but the downside is that the memory bus remains unchanged
at 128-bits wide and supports a maximum memory speed of DDR400.  So,
while single core Athlon 64 and Opteron CPUs get a full 6.4GB/s of
memory bandwidth, today's dual core CPUs are given the same memory
bandwidth to share among two cores instead of one.

AMD's solution to the problem will come in the form of DDR2 and a new
socket down the road, but for now there's no getting around the memory
bandwidth limitations.  Intel is actually in a better position from a
memory bandwidth standpoint. At this point, their chipsets provide
more memory bandwidth than what a single core needs with their dual
channel DDR2-667 controller.  The problem is that the Intel dual core
CPUs still run on a 64-bit wide 800MHz FSB, which makes Intel's
problem more of a FSB bandwidth limitation than a memory bandwidth
limitation."

So basically...  I would pretty much be buying an already outdated
technology if I were to purchase a dual Xeon or a dual Opteron system
now?

I guess the other advantage is that a good dual Xeon system with 4GB
RAM will run me around $3000, whereas a dual Opteron (with dual core)
system with 4GB RAM will run me more like $4300.  If the Opterons are
currently at their memory bandwidth limit, I will have spent the $4300
for nothing, especially since I need the fastest memory integration I
can get for my codes.

Would I be better buying a dual Xeon system if I needed to buy right
now instead of waiting for the bandwidth issue to be resolved?

-- 
gentoo-user@gentoo.org mailing list

Re: [gentoo-user] hardware advice for dual-processor set-up on gentoo

[Bob Sanders]

On Mon, 12 Sep 2005 23:47:11 -0500
Denis <denis.che@gmail.com> wrote:

> I guess the other advantage is that a good dual Xeon system with 4GB
> RAM will run me around $3000, whereas a dual Opteron (with dual core)
> system with 4GB RAM will run me more like $4300.  If the Opterons are
> currently at their memory bandwidth limit, I will have spent the $4300
> for nothing, especially since I need the fastest memory integration I
> can get for my codes.
> 
> Would I be better buying a dual Xeon system if I needed to buy right
> now instead of waiting for the bandwidth issue to be resolved?
> 

Careful with the dual Xeon - Intel has numerous chipsets.  Some better
than the other.  Unless you spend hours studying the difference, you may
end with much older tech for your money.

Also, you might be better off now with a 2P Opteron, single core, than
an Intel setup.  It's less expensive.  And, as you're crunching a lot of numbers,
the Opteron's faster throughput in the FPU may offset and bandwidth limitation.
 
Only you can tell if your app is more cpu/fpu bound or more memory bound.  You
might want to emerge -  app-admin/sysstat, and characterize your app's system
usage and use that to decide which arch features are important to you.

Another thing to consider - Intel shares the memory/FSB.  Each Opteron has access
to a full 6.4 GB/s memory bandwidth, as long as the data set remains with that cpu.
Should the data set or data have to come from a non-local memory bank, there will
be a delay.  So even with a slower memory bus, the Opteron could be faster overall.
It depends on what resources your app uses.

Bob
-  
-- 
gentoo-user@gentoo.org mailing list

Re: [gentoo-user] hardware advice for dual-processor set-up on gentoo

[A. Khattri]

On Mon, 12 Sep 2005, Denis wrote:

> So basically...  I would pretty much be buying an already outdated
> technology if I were to purchase a dual Xeon or a dual Opteron system
> now?

One could say that about any technology you buy ;-)

> I guess the other advantage is that a good dual Xeon system with 4GB
> RAM will run me around $3000, whereas a dual Opteron (with dual core)
> system with 4GB RAM will run me more like $4300.  If the Opterons are
> currently at their memory bandwidth limit, I will have spent the $4300
> for nothing, especially since I need the fastest memory integration I
> can get for my codes.
>
> Would I be better buying a dual Xeon system if I needed to buy right
> now instead of waiting for the bandwidth issue to be resolved?

It has to be said: Intel have been completely outmaneuvered by AMD with
respect to multicore chips. Intel have been chasing faster clock speeds
with larger transister counts while AMD have been pursuing a smarter
solution IMHO. I think it will be awhile before Intel starting cranking
out decent dual-core chips. Dont forget AMD have quad-core chips in the
pipeline too so they will be maintaining their lead for awhile.

As far as multicore support in boards go, last time I looked, Tyan seemed
to be in the lead with this. They have a quad-cpu board (effectively 8
cores when using dual-core chips - each chip has its own memory slots
with up to 4 or 8Gb per CPU). Tyan also now have a way of connecting
two quad-cpu boards together allowing you to build a 16-core Opteron
system. You could always buy a quad-core board and just keep adding
CPU's to upgrade and eventually add the second board when you need more
CPU ;-)


-- 

-- 
gentoo-user@gentoo.org mailing list

Re: [gentoo-user] hardware advice for dual-processor set-up on gentoo

[Dave Nebinger]

> I was under the impression that the Opterons didn't have the same type
> of a NorthBridge bottleneck that Intel processors experience and were
> thus quite a bit more efficient in the way they integrate with RAM and
> themselves!...  In fact, from reading the numbers posted on the AMD
> website comparing FSB and memory bandwidth, the numbers for the
> Opteron were much superior to those for Intel.  Reading what you wrote
> would make me think that the numbers AMD published were some kind of a
> marketing ploy??
>
> The numbers I am referring to are in this PDF:
> http://multicore2.amd.com/Products/CompetitiveComparisons/2P_Server_Comparison.pdf

Dude, you really should know by now that all of the numbers coming from a 
vendor and some of the numbers from 'independents' are always worked out to 
put their product on top.  [I say 'independents' in quotes because even 
sometimes those folks have an agenda that isn't always clear at first 
glance, and it also is unclear where they get their financial backing, i.e. 
are they in bed with Intel or AMD].

Stick with those that have community backing, namely sites like Anandtech 
and/or Toms Hardware.  You'll get more of a straight deal from them than any 
others I've seen.

-- 
gentoo-user@gentoo.org mailing list

Re: [gentoo-user] hardware advice for dual-processor set-up on gentoo

[Denis]

I read AnandTech.  And many other reviews by now.  But since I've been
out of hardware buying venture for a long time, I figured I'd read up
on the specs directly from the manufacturers' websites first and then
the reviews.  I can't say I am handy with different relationships
between front size bus speeds, system clock, and memory transfer
rates.  The point that Bob brought up about memory bus limitations was
very specific and only appeared in a couple reviews that I could
locate when I knew what to look for.

The general spirit seems to proclaim AMD ahead of the game, leaving
Intel in the dust.  However, there are things where Intel is still
ahead - such as areas of specialized scientific computing, for
example.  For example, I can get a 4-thread capability much cheaper
from Intel than from AMD, thanks to their much-criticized
HyperThreading technology.  Hyperthreading has been excellent for my
particular application of computing.  So, if I can build a good Intel
workstation with will give me 4 threads for around $2,000 instead of a
similar AMD workstation with 4 threads for over $3,500 - then I'd
rather stick to Intel on my budget.  At least for now.  Perhaps, in a
year or so, I'll migrate to AMD if Intel hasn't come up with something
suitable for my computing needs for a reasonable price.  I am sure
many people will disagree with what I am saying here, and I am not
trying to start a flame war over preferences, but in the case of
highly multithreaded computing in my case, this solution seems to make
sense right now.  For people with less specific needs, a dual AMD box
with single-core processors would probably make more sense on the same
budget.

-- 
gentoo-user@gentoo.org mailing list

Re: [gentoo-user] hardware advice for dual-processor set-up on gentoo

[- -]

[-- Attachment #1: Type: text/plain, Size: 560 bytes --]

On 9/12/05, Bob Sanders <rmsand@concentric.net> wrote:
> 
> Intel's compiler fairly cheap - approx. $600. Free for non-commerical
> home use.



This is the first time I heard of intel compilers and I am using dual
3.2GHz irwindales with 1 mb cache each and 2 GB of ram. Is there any
advantage
to using these compilers over GCC? What performance gain can I expect?

And more on topic: the dual 3.2 GHz irwindales run like a charm. I think 
that installing my entire system from stage 1 to full gnome took 
approximately 5 hours in compile time.

[-- Attachment #2: Type: text/html, Size: 1052 bytes --]

Re: [gentoo-user] hardware advice for dual-processor set-up on gentoo

[- -]

[-- Attachment #1: Type: text/plain, Size: 258 bytes --]

After a google search, it seems like the ICC compiler compiles faster and 
runs certain programs better. Gentoo has a package, can anyone say if the 
ICC compiler has any issues compiling common packages such as the gentoo 
base packages, gnome, or kde?

[-- Attachment #2: Type: text/html, Size: 267 bytes --]

Re: [gentoo-user] hardware advice for dual-processor set-up on gentoo

[Bob Sanders]

On Thu, 15 Sep 2005 19:27:08 -0400
- - <cornmander@gmail.com> wrote:

> 
> 
> This is the first time I heard of intel compilers and I am using dual
> 3.2GHz irwindales with 1 mb cache each and 2 GB of ram. Is there any
> advantage
> to using these compilers over GCC? What performance gain can I expect?
> 

It depends.  Straight compiles with no-optimization has shown them to
be faster in some case and slower in others.  If you have a specific application
set that you can actually hand code a few things, the Intel compilers will
take advantage of most of the features, gcc doesn't optimize.

Some folks have gone with the Intel compilers for the entire system, but I've
not heard of any reported results from their efforts.

You can go over the SpecOrg and look at the results of the INT/FP results.  All
the Intel results are with the Intel compilers.  Look at the test make up - which programs
they used for testing, and see if it matches your workload.  Then run the same thing
on your currect system to see if it comes close or wildly  different.

Bob
-  
-- 
gentoo-user@gentoo.org mailing list