Re: Number of cores and game performance

On 08/25/2013 12:46 PM, Scott Swinyard wrote:
>
> This will be somewhat of a longer post than it would have been because I
> am going to include an email transaction between myself and a friend who
> is more technically knowledgeable than myself for perspective.
>
> I wrote:
>
> I can’t find the answer on the web.
>
> It would be pertinent to single threaded games
>
> Which is faster an old single core cpu or a single core from a new
> multi core processor? Is there a difference? How much?

I don’t think there is a old single core cpu that could keep up with a single
core from most contemporary CPUs, however, I’d still avoid the low end… just
saying.

>
> ut2004 is very cpu dependent I understand, is single threaded
> basically, runs like s**t in Linux and if anything it seems slower in
> my new machine than it was in the older p4s. I’m wondering why.

I’ve run ut2004 for many, many years on some very old processors, I know for
certain that a 2.4Ghz P4 is more than enough. But you also have to remember
that’s there’s a lot more “loss” by running old architectures. Lack of
contemporary peripheral support (e.g. USB 3.0), expensive memory costs, limited
memory options, slower disk option, disk options that are getting rare and
relatively expensive, etc.

>
> His reply:
> Depends how the cores are optimized or how many cycles each
> instruction takes. That’s what MMX was all about, reducing the
> instruction cycles that common instructions take. The new multi-core
> cpus should be running at a higher clock speed so I would think they’'d
> be faster just 'cause. Some older games don’t like multi-cores, so you
> need to run it under just one core to see if it runs better. In
> Windows you go to task manager and right click on the app, then select
> cores to use. If you don’t specify single core it tries to use
> multiple and some games run sloooooow. Linux, I don’t know. Maybe it
> has something to do wth the video driver in Linux. It can’t be a speed
> issue because the new stuff beats the old.

In most cases, most games don’t exploit the multiple CPUs, however, Linux isn’t
Windows, so it actually can do productive things in parallel… that is via
separate processes, which certainly takes advantage of there being multiple CPUs.

>
> ------------------------------------
>
> My question to you here in the forum is: is there a way to specify the
> number of cores a specific application will use under Linux?

Uh… well, yes… you can dedicate CPUs to processes… BUT, I have found that
the “benefits” of doing so usually doesn’t warrant it. Some may have found the
feature interesting though.

man numactl
(some have also mentioned cgroups… that may also be able to create process
sets and CPU relationships)

Again, if numactl is applicable, IMHO, you’re likely running an architecture
that is more than able to handle ut2004 and whatever else you are doing (again,
possible avoiding the lowest end… especially Intel).

A midrange ($40 or less) Nvidia card is more than able to handle ut2004.

I have not experienced the poor ut2004 performance you mentioned… I’ve run it
on everything from a Dual Athlon host, to a dual P4 box, to my current dual
E5460 host. While you do see “dual” in my configs, ut2004 should scream on
current sub-$500 single socket systems. IMHO… for what it is worth.

Oh… and I run it at 1920x1200 with all features on (and mine has the latest
patches… which I think can be hard to find nowadays).

From an avid ut2004 user…

On Mon, 26 Aug 2013 00:46:01 +0000, Scott Swinyard wrote:

> Well, I ran the game with taskset and unless I did something wrong it
> doesn’t make any difference, so I shut off all cores except for one in
> the bios and there was still no difference.
>
> Soo…perhaps that isn’t the problem huh?

It could be (and probably is more likely) video card performance.

Jim

Jim Henderson
openSUSE Forums Administrator
Forum Use Terms & Conditions at http://tinyurl.com/openSUSE-T-C

On Mon, 26 Aug 2013 03:36:01 +0000, Scott Swinyard wrote:

> Is there something specific you are thinking?

What kind of video card is in the system, and what video driver are you
using?

Jim


Jim Henderson
openSUSE Forums Administrator
Forum Use Terms & Conditions at http://tinyurl.com/openSUSE-T-C

On Mon, 26 Aug 2013 17:26:02 +0000, Scott Swinyard wrote:

> hendersj;2581782 Wrote:
>> On Mon, 26 Aug 2013 03:36:01 +0000, Scott Swinyard wrote:
>>
>> > Is there something specific you are thinking?
>>
>> What kind of video card is in the system, and what video driver are you
>> using?
>>
>>
>>
> It’s right there in the post you are replying to. Amd 7870 and Amd
> proprietary drivers.

Sorry, I should’ve seen that - so that’s the Radeon HD 7870, it looks
like - which particular AMD proprietary drivers? fglrx, fglrx_legacy -
32-bit, 64-bit?

If you run glxgears, what sorts of framerates do you see reported?

Jim


Jim Henderson
openSUSE Forums Administrator
Forum Use Terms & Conditions at http://tinyurl.com/openSUSE-T-C