Interesting GPU/CPU Usage
 

I was just running the London free flight to watch my GPU and CPU usage to see how lots of buildings affect them. I dropped down to around 2000 feet and started following the river from the Tower Bridge Eastward to the sea. While over central London the GPU usage fluctuated between 70% and 80% which I thought was pretty low considering the buildings. I have “Unlimited Building” configured. The CPU usage was distributed fairly evenly over 4 cores running around 50% to 60% on each. The CPU usage stayed consistent for the rest of my flight. However, as I left London and got into the country side the GPU usage maxed out and stayed there until I quit the mission. That is exactly opposite of what I expected. Also, as I posted before, when the GPU maxes out I start seeing usage on the second GPU (not running SLI).

As for I/O I was just watching the HD access light which only blinked once or twice a second throughout the flight. If there was a lot of I/O going on it was happening mostly in the RAID cache.

Anyone have an explanation?

alot of bugs? :grin:

Try to go under 200 ft. over London and there the fps get a big hit. Especially over the Tower, the Parliament and Buckingham Palace... But in a real fight it never happened.:rolleyes:

Does that 1C splash screen bug still happen where it makes GPU's run really slow clock speed?

I'm running the official version of the game (no beta patch) with an ATi 5850 should I get rid of this screen? Or is this an old issue?

I've done the low flight thing many times, but I wanted to see how the CPU and GPU usage looked over varying landscapes. What I am seeing looks like the GPU is begin under utilized in some cases for some reason. In other situations like in a typical combat mission over the channel, the GPU stays maxed out as I would expect.

I've had the same experience regarding gpu usage, however my gpu usage as measured with afterburner has gone up significantly (from 60-80% to 80-99%) after the beta patch, which I do see as an improvement.

most probably the cities take a lot of cpu power as well as gpu power. Think about all those LOD swaps and all the data that has to be sent to gpu. gpu is not showing 100% usage because it was waiting for the cpu. therefore in that situation the cpu is the bottle neck.

In the countryside there's not a lot of the cpu to do so the gpu is able to run at full tilt.

But the CPU usage stays relatively low and does not fluctuate regardless of the GPU usage.

that's more than likely windows spreading the threads across all available cores. try it with a game you know is single threaded and you'll see spread 50/50 (if you're running a dual core) even though it spreads the threads it can never go above 100% total for a single thread.

plus as cod is multi threaded (I think) there could be situations where 1 thread is stalled waiting for another thread to release the data it want's to work on. this can stall the cpu also.

I suspect (I would welcome clarification from someone who really knows) that Hyperthreaded CPUs only ever run up to half speed, because there are half the number of cores that Windows thinks there are, and TANSTAAFL.

If you disable hyperthreading in Bios, will it use 4 cores 100%, instead of 8 virtual ones at 50% ?

Not sure about this, but also could be that shaders to render terrain were a lot more expensive than shaders to render buildings. Also trees have a lot of geometry, same or even more than buildings at similar distances. If all this is the case that could be a lot less work to gpu in city that in landscape.

You also need to look at the utilisation of the VRAM. The moment your VRAM is full, the GPU will start swapping in order to accomodate for the new graphics. This is when your GPU utilisation goes down (and your fps too) because the bottleneck becomes bringing the data in for the GPU to process them.

Test also flying over the same area above London a second time. You will see a much smoother fly-by the second time (provided the data is still in the memory of you GPU).

Over the sea you do not have any objects to load. Both GPUs (if SLI) work 90%
Over an "empty" (not a lot of objects) map neither. Both GPUs (if SLI) work 70-90%
Over the same map full of objects in order to max the available VRAM of your card, you see the problem. Both GPUs (if SLI) work 50-70%

Look at http://forum.1cpublishing.eu/showthread.php?t=23199


Once or twice per second HDD access is a lot (for me) and shows the amount of data that needs to be loaded.
For me this was solved and I got smoother gameplay by creating a RAMDISK and loading everything there. The new RAMDISK solutions posted in the forum are much more advanced than the ones I knew in the past and made the difference.

~S~

Most probably your GPU was the bottleneck over london. Not only Vram usage, as said above, but geneal computing power of the GPU. (Needs to shade all the buildings etc) Thus, the CPUs did not need to compute to their full power, as the GPU could not accept new instructions. (The maximum prerendered frames setting in your nvidia control panel affects this too, as this is the amount of frames the GPU renders ahead, if the GPU is stilly busy and does not accept the CPU date at the moment). When leaving london, the GPU usage decreased and now the CPUs could be used more, as the GPU was accepting new data faster then over london.

The fact that you see increased usage of the second GPU (not in SLI) when the first one saturated might be the nvidia driver using the 2nd GPU for the windows background processes.

I noticed that too. The VRAM gets fully stretched within seconds after entering the scene. As far as I understood the VRAM cache gets cleared automatically to ensure that there is always enough free VRAM to run the application and to avoid that kind of bottleneck. IMO this does not work correctly as the VRAM is always around 100% workload.

No it is not Icebear, but you must have lots of it ;)

It appears the max VRAM used was 2,1Gb over London (your mileage may vary depending on the resolution you play I presume).

So, if your card has 1Gb VRAM you need to be very consious on how much graphics detail and how heavy the map is you fly on.

My 1,3Gb VRAM makes many maps playable but I immediately notice when the limit is reached (halved fps).

~S~




PS. Antartica!? Say hi to the icebears from me, if you find them ;)

Windows recognize both physical and logical cores as independent unit, in fact prior to Win 7 the OS thread scheduler not even cared if a core was physical or logical.
The Windows task manager shows the average of all CPU cores usage including logical cores but also can show (depend on configuration) a graph for each core, whether it is physical or logical.

The HT cores are just parked with CoD whereas the real, physical cores are active with CoD, but cpu power is not the issue with this game.

An i7 or fast i5 is more than enough. Heck, even when I underclock my cpu to 2.8 Ghz it still runs pretty good.

It's just the buggy 3d mode (full, pseudo..) and gpu clock speed that worries me. Sometimes the game starts and my vid card stays at 157 Mhz no matter what. I shut it down and change to pseudo, and all of a sudden the vid card is now at 850 Mhz. Next time, nothing has changed in between, it's back at 400 Mhz and sometimes even back to 157 Mhz.

This is really weird game behavior which is a bit unexpected.

Rgs,
FP

For what its worth, when I watch CoD CPU usage I do notice that only the odd numbered cores show usage. The 4 physical cores I would guess.

Yep, but this is a driver bug, you can't blame devs for this

It is? AMD is aware of this bug and 1C raised it to AMD or is it because the game does not really enter 3d mode?

Rgs,
FP

What do you mean by "the game does not really enter 3d mode"?

Is the driver that has to set the graphics card in "3d mode" when an heavy task is detected, NVIDIA's cards does not have this problem.

Let me see, have you removed the small Ubisoft video just before the loading of CoD?
If not, do so and it will probably solve your issues.

~S~

Well, I mean real full screen. Not a stretched window or something else.

Yes, also tried to remove the welcome wmv, but it does not make a difference. Are there any other work arounds to raise the 3d clock?

Rgs,
FP

Deleting the Ubisoft video works for me too, although the slow-down in game isn't as obvious with the new Beta patch. I have MSI Afterburner running all the time on a G19 screen and consequently noticed that it's not only the Ubisoft video that causes the problem. I sometimes see GPU 1 memory speed locked at 900MHz (I've not yet isolated which other software causes this but I believe I've seen posts here identifying the cause, it's usually got 1200MHz to use). I need to reset PC to unlock the memory frequency.

It's an XFX-5970-BE and this Beta patch runs lovely on it.

It doesn't matter if it's full-screen, windowed or pseudo, this is not the way drivers recognize a workload that require a "full performance" state, there are many graphics app that can run windowed, including most of the flight simulators

Nevermind, I completely removed 11.8 and installed Ati 11.9 and now the clocks go to maximum speed. For me, 11.9 seemed to have fixed it.

Rgs,
FP