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javelina

Multi core

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Maybe going down a rat hole here, nonetheless. My rig: using an i5-4670k, O/C to 4.2ghz, hyperthreading off, and 16GB RAM.

 

While tinkering with DCS, I came across a good thread regarding the CPU affinity. In particular, since DCS can only use (2) cores, (one core for the .exe, and the other is used for the sound thread). Why not set the affinity so the appropriate .exe stays on the same cores. Instead of bouncing around, amongst all of the cores, (which might have a little performance impact). In particular, it appears the O/S likes to run a lot of processes on cores 1 & 2. So I set the DCS.exe to run only on cores 3 & 4, to free up the simulation .exe from competing with O/S processes on 1 & 2.

 

http://forums.eagle.ru/showthread.php?t=118535&highlight=cpu+affinity

 

So for BoS, i've enabled the affinity setting, via the O/S task manager. Started up IL-2, jumped in an A/C and started flying. Then paused the game, brought up task manager, and hunted down the IL-2.exe. From there, I set the CPU affinity to only use cores 3 & 4.

 

Sure, my i5-4670k runs BoS fine, but I'm also AMD challenged a bit with my GPU. :-)

 

Any rate, just wanted to share, and hear any thoughts from the group.

 

-Jav

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Hi Jav!

 

I've see you at the ED forums as well :-)

 

Thx for bringing this very interesting point.

 

AM tweaks are what I have used in the past to tweak FS9, FSx, P3D... I became aware of that thread at the ED forums last week, and it's something I really want to try out because I also have an i5 2500k

 

Will try your suggestion. Apparently we can do it in a config file in DCS, just like in MSFS, I wonder if there is also some place where we can force it in IL2 BOS?

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doesn't really buy me anything... was an interesting experiment nonetheless.

 

after manually setting the affinity to cores 3 & 4, the sim flew just fine. But I noticed my Esc key wouldn't work, to let me end the flight session. Wondering if I need to set both the IL2.exe & Launcher.exe as well, (for the same affinity).

 

gonna abandon the effort, just wanted to experiment.

Hi Jav!

 

I've see you at the ED forums as well :-)

 

Thx for bringing this very interesting point.

 

AM tweaks are what I have used in the past to tweak FS9, FSx, P3D... I became aware of that thread at the ED forums last week, and it's something I really want to try out because I also have an i5 2500k

 

Will try your suggestion. Apparently we can do it in a config file in DCS, just like in MSFS, I wonder if there is also some place where we can force it in IL2 BOS?

that's exactly what I do at DCS, set it in the user config file, via the autoexec.cfg file.

 

I was hoping BoS had a similar capability to force it. will hunt around. :-)

Edited by javelina

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have tried this some time ago and just got worse performance and higher core loads. When all 4 cores are available for the game, the cpu load is more or less evenly distributed among all 4 cores and is between 40 and 85% most of the time. If I restrict the affinity to 3 or 2 cores, the load percentages explode to 90-95 and I lose 20-25% fps.

The problem with DCS is that it has dated engine and does not support multi-core processors well. BoS's digital nature seems to use all the cores you throw at it.

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It has been said by the devs, a few years years ago, talking about RoF, that DigitalNature engine is optimised for multi-core CPU. DN engine is optimal with 4 cores CPU (in RoF at least), as they said.

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You don't want to limit this to two cores if you have four physical cores - there's a reason the recommended minimum CPU on the main webpage is a quad core and not a duo/dual core. This engine will take full advantage of all four cores, and going with process affinity is actually going to cripple performance. Tab and Nonolem are absolutely correct. Don't use DCS as any benchmark for anything other than DCS, and that goes for all other games. They are all programmed differently.

 

Minimal System Requirements:

To understand if you PC can handle IL-2: BOS we recommend using Rise of Flight as your benchmark - the recommended system requirements for Rise of Flight are found below.
Rise of Flight is available for free and you can download and play by going to the following link - http://riseofflight.com/tryrof/en.
We recommend these system requirements as the minimum specs for IL-2: BOS.

  • Windows® XP (SP2) / Vista (SP1) / Windows® 7 (SP1) / Windows® 8
  • CPU: Intel® Core™ 2 Quad 2.6 GHz+ or Intel® Core™ i5/i7 2.6 GHz+
  • GPU: 1024 Mb+, GeForce GTX 260+/Radeon HD5850+
  • RAM: 4 Gb+
  • Sound: DirectX 9.0c/11 compatible
  • Free Hard Drive space: 10 Gb+
  • Internet Connection Required for Registration, Career Mode, Multiplayer and Statistics Tracking. 256 Kb/s for single-player and 1 Mb/s for multiplayer
Edited by FuriousMeow

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Good input, and appreciate the feedback! many thanks for the education. :-)

 

-Jav

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have tried this some time ago and just got worse performance and higher core loads. When all 4 cores are available for the game, the cpu load is more or less evenly distributed among all 4 cores and is between 40 and 85% most of the time. If I restrict the affinity to 3 or 2 cores, the load percentages explode to 90-95 and I lose 20-25% fps.

The problem with DCS is that it has dated engine and does not support multi-core processors well. BoS's digital nature seems to use all the cores you throw at it.

It seems my pc is showing 10-15% load at most at any point. Not sure how to get it to use the remaining available cores beyond the four already loaded.

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So can anybody say with any certainty if it would be better to run my I7-3820 with the hyperthreading on or off since it appears the game is optimized for 4 cores? Turning the HT off in my case would have me running just the 4 physical instead of 4 physical and 4 logical cores. I have a 4.3 overclock right now but I can acheive a very stable 4.625 overclock with the HT off.

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I run my 4820K with Hyperthreading on, and get excellent performance, currently clocked at 4.50 ghz

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I run my 4820K with Hyperthreading on, and get excellent performance, currently clocked at 4.50 ghz

Your specs are very similar to mine. Can you tell me if you have tried BoS with your HT off and noticed any difference? My rig runs the game good as well, but I am always looking for those few extra frames. I will test it myself also, but was curious to see if you have, to eliminate the placebo effect. Edited by TooBeaucoup

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Your specs are very similar to mine. Can you tell me if you have tried BoS with your HT off and noticed any difference? My rig runs the game good as well, but I am always looking for those few extra frames. I will test it myself also, but was curious to see if you have, to eliminate the placebo effect.

 

No I have not , since my performance is so good I really have not felt compelled to give that a try - I may though now that I am curious...

Edited by dburnette

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Your specs are very similar to mine. Can you tell me if you have tried BoS with your HT off and noticed any difference? My rig runs the game good as well, but I am always looking for those few extra frames. I will test it myself also, but was curious to see if you have, to eliminate the placebo effect.

 

Ok just did a quick test, using the same quick mission I have been flying in the QMB.

 

With Hyperthreading disabled, my fps are a little better, maybe around 10% -  but, as I mentioned my performance was already very good, so going from like 80-100 fps with Hyperthreading, to 90-110 fps app with it disabled.

 

But yes, I did see a little performance gain from having it disabled.

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Ok just did a quick test, using the same quick mission I have been flying in the QMB.

 

With Hyperthreading disabled, my fps are a little better, maybe around 10% -  but, as I mentioned my performance was already very good, so going from like 80-100 fps with Hyperthreading, to 90-110 fps app with it disabled.

 

But yes, I did see a little performance gain from having it disabled.

It looks like this is the case with me as well. I need to do more testing but it seems to me that I have similar performance gains with the HT off, in SP as well as MP.

Edited by TooBeaucoup

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It looks like this is the case with me as well. I need to do more testing but it seems to me that I have similar performance gains with the HT off, in SP as well as MP.

 

I re-enabled HT, simply because my performance was already really good, but this might also help those who need a little extra in the performance department.

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I re-enabled HT, simply because my performance was already really good, but this might also help those who need a little extra in the performance department.

Most guys with high spec systems have high res 60hz monitors so I guess if you are already getting above 60fps it won't matter anyway. I have a 1080 144hz monitor so I like to get as many fps as I can get. You can actually see the difference between say 80 or 100fps believe it or not. The old il2 looks and plays great at 144fps by the way. I think I will leave my HT off for now. Although it would also be interesting to test what would happen leaving it on and offloading the workload to 4 unused cores. It looks like the OP tried fiddling with the mask but he wrote that he only did it for 2 cores.

Edited by TooBeaucoup

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Most guys with high spec systems have high res 60hz monitors so I guess if you are already getting above 60fps it won't matter anyway. I have a 1080 144hz monitor so I like to get as many fps as I can get. You can actually see the difference between say 80 or 100fps believe it or not. The old il2 looks and plays great at 144fps by the way. I think I will leave my HT off for now. Although it would also be interesting to test what would happen leaving it on and offloading the workload to 4 unused cores. It looks like the OP tried fiddling with the mask but he wrote that he only did it for 2 cores.

 

I am actually running on an Asus 27" 144hz monitor.

 

Not sure I see a difference between 80 and 100 fps, but then my eyes are not as good as they used to be either.

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I am actually running on an Asus 27" 144hz monitor.

 

Not sure I see a difference between 80 and 100 fps, but then my eyes are not as good as they used to be either.

You have the same monitor as me. Well some guys say they can tell and some guys say they can't. Please tell me you got that thing connected using the dual DVI that came in the box and not a HDMI or single DVI. A lot of guys that have told me they can't see a difference had their monitor hooked up with the wrong connector and low and behold now they can see the higher frames.

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Can anyone verify that after minimizing the game, that more than one core is being used in its current state. My cores# versus time plot only shows one core(1st) being used consistently during flight. Thank you.

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Interesting conversation, what with the new intel Haswell-E cpu's released in last couple of days.

 

Very interested in how this simulation does with multi core CPU's and how scalable it is with multi CPU and multi GPU for future use too.

 

Thanks.

Edited by Katana1000S

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