speed performances / hardware / cpu

Thread view:

antoine - 16 Nov 2006 02:10 GMT

Hello,

I'm developing / supporting a java "client" application (running on PCs
with XP pro, jre 1.5) which is a high performance trading client. it
receives market updates, displays them on screen (swing), does a serie
of computation, and performs several actions based on computated values
(order sending, cancelation, etc...). it is designed to run for 8 hours
straight without interruption, does not access any database, only uses
socket-based I/O, and is correctly multi-threaded.

I'm looking at upgrading our workstations, to hopefully get a speed
increase. currently, our "base computation" routine takes around 5ms
average, and I'm looking at reducing this number (I'm also looking at
improving CODE performances, but this post is about hardware).

currently we're running on dual CPU intel Xeon 2.8GHz, roughly 3 years
old, with 1GB RAM. virtual memory usage is around 128MB, so I believe
RAM is not an issue.

which kind of upgrade would sound smart to you ? I've seen technologies
like:
- all the "dual core" family
- 64-bit architecture (although no JVM for intel on XP pro 64-bit)
- simply pushing the frequency to 3.6GHz...

does 64-bit make sense ? or is it only for memory intensive application
(we're more concerned with execution speed) ?

any insight or link to any informative page would be most welcome !

thanks

-Antoine

Reply to this Message

Daniel Pitts - 16 Nov 2006 02:20 GMT

> Hello,
>
[quoted text clipped - 29 lines]
>
> -Antoine

Its hard to say without testing your particular code on the different
types of upgrades.
If your code can utilize multithreading effectively, I would probably
look into dual core (or quad processor) technologies.
There is a 64 bit JVM for Linux, and it might provide a boost.
Actually, just move to Linux may provide a slight boost.
Its really hard to say exactly what will be the most cost-effective
upgrade without actually testing results. I suggest you talk your
distributor into allowing you to run some custom benchmarks. Ofcourse,
the benchmarks should accurately reflect the profile of your
application.

Reply to this Message

Arne Vajhøj - 16 Nov 2006 02:57 GMT

> I'm developing / supporting a java "client" application (running on PCs
> with XP pro, jre 1.5) which is a high performance trading client. it
[quoted text clipped - 23 lines]
>
> any insight or link to any informative page would be most welcome !

I agree that more memory will probably not help.

Higher frequency will almost certainly help (3.6/2.8 is +28%, but it
is not certain that the GHz are divideable like that).

Switching to 64 bit in itself does increase calculation speed, but
because x86-64 has more registers than x86 it may actually give
some (like +10%).

If you can parallelize to 4 execution units then 2 dual core CPU's will
certainly give a huge jump compared with the current 2 single core
CPU's (like +80%).

If your app frequently access data in the few MB range, then the
extra L2 cache in newer CPU's may also help.

Arne

Reply to this Message

Eric Sosman - 16 Nov 2006 03:37 GMT

> Hello,
>
[quoted text clipped - 25 lines]
>
> any insight or link to any informative page would be most welcome !

Not to be unduly harsh, but all these upgrades would be
STUPID! -- until you've measured what's happening on the current
hardware. You've already made a start by measuring the memory
usage, and that's good. Now measure the other components that
you might upgrade: How much CPU are you using, how much time do
you spend waiting for disk I/O, are you drowning in cache misses,
and so on and so on. If the real problem is (for example) a
network transaction, making the client machine faster just makes
it wait faster.

Continue as you have begun: Measure the consumption of the
different resources, and try to determine what is holding you
back. From your description there's an excellent chance that the
scarce resource is in fact CPU power -- but won't you feel silly
(and impoverished) if you spend a lot of money upgrading the CPUs
only to discover that the real bottleneck was the El Cheapo
graphics card?

Carpenters have a motto: "Measure twice, cut once." For some
reason, computerfolk seem resistant to that wisdom. Buck the trend,
and spend your money ("cut") only after you've measured. Be a
carpenter!

Signature

Eric Sosman
esosman@acm-dot-org.invalid

Reply to this Message

bugbear - 16 Nov 2006 10:20 GMT

> Hello,
>
[quoted text clipped - 10 lines]
> average, and I'm looking at reducing this number (I'm also looking at
> improving CODE performances, but this post is about hardware).

If this is the "limiting path" (I assume you've profiled(*))
you could run at 200 FPS, which is faster than normal
screen refresh.

So I don't see your problem.

BugBear

(*) if you haven't profiled, you're wasting your time, and your employers's
hardware money.

Reply to this Message

Nigel Wade - 16 Nov 2006 12:31 GMT

> Hello,
>
[quoted text clipped - 29 lines]
>
> -Antoine

Firstly I'd verify that the code is really taking advantage of dual CPUs and is
not wasting CPU cycles by having threads waiting on locks, or cache thrashing
due to each thread/CPU modifying the same data concurrently. Secondly, you need
to determine what is the major bottleneck in the current system. Is it CPU,
memory bandwidth, PCI/graphics latency, network latency etc. Until you know
this you have no idea where to spend your money effectively.

The only way to really know what is best is to actually run your code on various
systems. It's not just about pure raw CPU cycles, GHz etc. It's also about the
support chipsets, how well the motherboard is put together, how well the multi
processors can manage cache coherency, and other very esoteric hardware issues.

Signature

Nigel Wade, System Administrator, Space Plasma Physics Group,
University of Leicester, Leicester, LE1 7RH, UK
E-mail : nmw@ion.le.ac.uk
Phone : +44 (0)116 2523548, Fax : +44 (0)116 2523555

Reply to this Message

speed performances / hardware / cpu

Free Magazines