Dual Core and Old Game

I have just made a very interesting discovery. I play an old game from 2001 called Red Ace Squadron. I track CPU usage using MBM, which of course records highs and lows. I start the game with both cores at zero usage and just wiped clean so 0 is both the high and the low. I played the game for about 15 minutes and closed it. The high CPU usage in core ) was 86% and in core 1 was 54%. This means that this very old game title made considerable use of both cores. I was surprised to see this and now I will check it out in other games.

wow. I only noticed that once too but i thought it was just my computer.

May be your "background tasks" were using your Core 1 too while you were playing your games?? Were you running anything specific at the background while playing your games, such as Anti-virus, burning CD/DVD etc??

I would think the task threads would be listed IE he would know what the cores were running, that is if its a decent program (not dual core just yet ) LOL

I think 54% is high for background tasks, not only that, but it does it consistently. If it's not real then it is more likely the fault of MBM as I am shocked this old game uses so much CPU cycles.

The only plausible thing that seems to be is that the graphics drivers mite be taking a chunk on the other cpu?

i don't know. ive noticed this too but its just odd.

Jedi Outcast did this to me the other day.

I tried setting affinity, and of all things, it caused the game to crash. Apparently now that it knows I have dual cores, it needs them?

yeah it was odd BF2 seems to do that to me

SMP DOESN'T send one task / thread to one core. It spreads the tasks out evenly between processors. If some program were to have a bunch of sequential bits of calculations disconnected from eachother, they would likely be sent to alternating processors.

Its not "multi threaded" because its not doing two things at once.. Its still doing one at a time, its just sharing it between two processors.

Only things that are purposefully coded for one processor (or when you set affinity) go to ONLY one processor.

So, your game could be SMP aware, or your operating system could just be doing exactly what it does :- ]

try a new game and then check the precentage used

Older games take more cpu power then most people think.
Since your using dx9 on a non dx9 game the cpu has to do more work.
There is actually little video card usuage. If you overclock the videocard it will
still be about the same FPS as stock.
That's why theres such a huge difference between the CPU stock and OC scores
with 3dmark2001 with a dx9 setup.
Pretty much the cpu is doing all the work for the video card.

I think modern operating systems try to shuffle the processes all around between the cores if it makes sense.

Yes, threads jump back and forth from core to core.

JCLW said:

Yes, threads jump back and forth from core to core.

Click to expand...

So you are saying that they are really not using both cores simultaneously? I have no way to track this in game as I'm only looking at the peak levels after the game is closed.

Yes. Task manager will track individual core usage for a short time, so you can watch it there.

JCLW said:

Yes. Task manager will track individual core usage for a short time, so you can watch it there.

Click to expand...

Good idea. I'm glad thought of it!
Well, I checked it out and the game is using both cores simultaneously as I originally thought. It does use one core more heavily, but none the less it's getting substantial help from the second core. I would imagine that if the load could be distributed more equally there would be a greater performance gain, but I'm sure it's got to be benefiting lesser load on the second cpu.

This should be expected. Just about any program more complex than beginner programs use multiple threads, even if most people don't realise it.

For example: any program that allows you to interact with it while it is busy. A program may be burning a CD, or compressing a video, etc, etc. However, most of the time, you can still interact with the window - resize it, move it, use the menu buttons, etc. Most programs use a seperate thread to handle the GUI. You can tell the ones that don't.

When you have a window that is busy, and you drag it, and the contents are replaced by gray or glitchy looking still images of the window's movement across the screen, it is single threaded. It is busy, so it can't provide the window manager with the information it needs to draw the program.

When a window is busy and you move it but it looks OK, it is multithreaded. One thread for GUI, one for work. On a single core/cpu computer, the OS's scheduler simply tells the CPU to stop crunching numbers for a second, process the GUI, the resum crunching numbers. So quickly, you would never know. On a multi-core/cpu system, the other core handles it and processing is never interrupted.

So, many programs are multi-threaded. Making multi-threaded programs is not hard - we are doing it in first year Java here at UVic. What is hard is taking a single task and spreading it across multiple cores.

In this case, the first core might by running the application's main thread, which is doing most of the work. The other core is probably handling stuff like keyboard input, maybe some sound processing, etc - the background work for the game. A true multi-threaded game would take the most complex task of the game, managing the virtual world (moving 3d-objects, presenting them to the video card from the correct perspective for rendering, managing interactions, etc.) and split that over two cores. This is difficult, because many operations are dependent on the outcome of others, so it's hard to seperate tasks.

That explains it quite well, Stoanhart. However, I don't think people who think that single cores are still better for gaming have any idea what dual core benefits they are missing out on. All they are thinking is that if it's not optimized for DC that there is really little benefit.
BTW, good luck with school!
Rich