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Guest Ken_Salter

Hyper Threading and FS9

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Hi,I have a Pentim 4 3.02Ghz, and was wondering if using the hyper threading was of any benefit to FS9, or is it best to disable it ?Regards,Adam. :-shy

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I have the same system and was wondering about that, too.If the answer is "disable", how do you do that? I cannot find any instructions about disabling hyper threading.Thanks for the question.

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Adam, if I remember correctly, it was stated during the development phase of FS2k4 that it supports multiple processors, whether they be physical (dual CPU system) or logical (hyperthreading or any variant thereof) so I would think that enabling HT would provide more performance than disabling it. Only one way to find out though, setup a situation and record some frame rates with HT on, and repeat the same situation with HT off. Obviously the more situations you setup and the more times you repeat them, the more reliable your findings will be.And to the gentleman who posted below you, one should be able to enable/disable HT within their mobo's bios. hope this helps,Max Cowgill

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FS9 isn't multithreaded, meaning HT and dual CPU's wont help it at all. My friend has a dual Athlon MP system and he says it only uses 1 CPU, meaning its single-threaded. Its too bad its not multithreaded, because people with dual CPU systems would rock at running FS9 LOL. the Pentium 4 systems would see a marginal increase, but not a whole lot. But since its single-threaded, P4's wont see any performance gain/loss by turning HT on or off.

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Zack, this is contradictory to the information MS has put out regarding the use of multiple processors (physical/logical) and FS9. Do you have any other evidence to support your statement, other than the anecdotal evidence you've provided? I'm not saying you're lying, it's just odd that MS would claim support for dual processors/HT and the opposite would prove true.-Max Cowgill

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FS9 IS multithreaded. If your friend's dual athlon only shows one CPU running then its not configured properly. What OS is he using? My HT system clearly shows "both" CPU's heavily engaged with FS running.Even if FS WASN"T multithreaded itself, the dual CPU would still be much faster as the OS would offload background tasks to the 2nd processor. CPU load balancing is handled by the OS - not the application. A program that explicitly spins off different threads during execution simply allows the OS to do the job more efficiently. The app has no direct control over which CPU will run which thread.Adam, I can't imagine any reason beyond pure diagnostic testing that you would ever want to disable Hyperthreading.BTW. I assume everyone knows that you must be running Windows 2000 or XP to take advantage of Hyperthreading. Win9x and ME don't support multiple processors.

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I assume everyone knows that you must be running Windows>2000 or XP to take advantage of Hyperthreading. Win9x and ME>don't support multiple processors. Unfortunately Windows 2000 does NOT support HT correctly--it does however support multiple processors. HT is the ONLY reason I would move from Win2K Pro to XP.Noel

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I never tought I would say this but...As it happens, I just had a strange experience with this very subject.Contrary to what MS say, I'm don't think FS9 does benefit from HT. I too thought that it would, I believe at one time they said the weather engine would run as a seperate process on HT, but I've never seen CPU usage for FS9 rise above 50% on my HT enabled P4C WinXP system-and I have tested with all sorts of benchmarks to make sure HT was set up correctly in the first place. Although FS9 may not benefit directly from HT, I figured that HT would still help performance by handling background tasks and such, so I did not think of disabling it before.Yesterday, RealityXP released the FS2004 version of their GPS530XP, and after installing it, I experienced big FPS problems. In the RXP forum, Jean-Luc suggested disabling HT...and the difference is astounding! FS9 is running MUCH smoother and faster than it ever did, and I'm now convinced that FS9 may be having problems dealing with HT, at least on my system; point is, disabling it didn't help just with the RXP stuff, but improved FS performance overall, with a lot less disk access. Maybe adding more memory might have helped too, but I cannot afford that right now.It's early days yet, and we're just starting to find our way towards better performance, and workarounds and tweaks may improve the situation later on, but for now, HT is off on my comp.P4c 2.6 @ 3.2, 512Mb DDR PC3500, Radeon 9700 Pro, SB Audigy2, Win XP

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Yes FS is multithreaded but what I want to know is what is happenning in a dual logical processors. I don't have an HT in a normal CPU FS9 presents 13 threads (with PMDG loaded) but only one as all the processing the others just sit there doing almost nothing. I'm using MS Spy++ to see the threads don't know if there is any other tool to investigate but I'm very interested to see what happens specially during a weather update.Jos

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Hi,If your OS is Windows XP(Home or Pro), including service pack 1:There is a problem with hyper threading.SP1 causes a dropdown in performance.Have a look in Microsoft's knowlegde base nr.815227Here's the link: http://support.microsoft.com/default.aspx?...kb;en-us;815227SP2 will fix this problem, but as you may know this will take some time......!!Following the above link gives you the possibility to ask for this fix at once!Regards Johan

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-"but only one as all the processing the others just sit there doing almost nothing.-" Have you noticed any difference between removing the cd after Fsim starts vs. leaving the cd in the entire time ?Kurt M

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You can disable hyper threading in the bios, but I would never advise anyone to do that. When running FS9, I never see it go beyond 50% on both processor instances. However, using UD to take use of the other half of the processing power results in a noticable slowdown. UD had never caused any slowdown on a non hyper threading processor. It seems there are some issues with task preemption once there is processor power available for other tasks, so while 50% of the processor is available when running FS9, I got a noticable improvement when turning off all background tasks such as UD, asus probe en mouse software.

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Seems though that many benefit from disabling it?!Also, don't expect much from Windows XP Home:The processor limits which result from this licensing model for 32-bit versions of the Windows Server 2003 family and Windows XP are shown in Table 2.Windows Version Maximum Physical Processor Limit Maximum Logical Processor LimitWindows XP Home Edition 1 2Windows XP Professional 2 4Windows Server 2003, Standard Edition 4 8Windows Server 2003, Enterprise Edition 8 16Windows Server 2003, Datacenter Edition 32 32Table 2. Processor Limits for 32-bit Versions of the Windows Server 2003 family and Windows XPAlso note there are 3 topics covered with HT:As a result of the HT processor identification support, the following HT-aware features are included in Windows XP and the Windows Server 2003 family.

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Please correct me if I'm wrong, but:1) FS9 is multi-threaded2) At least on Win XP Pro, there is support for multi-processors (real or "simulated")3) The OS is responsible for assigning CPUs to threads if the program itself does not careTherefore:How could FS9 not benefit from any multi-cpu configuration?http://saltydogfly2.avsim.net/images/avsim_sig.jpg"We are the music makers, and we are the dreamers of dreams."

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After doing a quick test I am beginning to feel that, to my dismay, FS2004 is indeed NOT multi-threaded.http://forums.avsim.net/user_files/32333.jpgI took this screenshot with clouds and complex mesh terrain in plain view, and the sim is not paused. As you can see, CPU 1 is running near the 100% mark whereas CPU 2 is running near the 0% mark.I did notice that the thread counter decreased upon exiting the sim, but I have no way to tell what threads where created to begin with.Take note that I have 2 physical processors (not hyperthreading). I do have a new hyperthreading laptop but I have not yet installed FS2004 on it, so I cannot comment on any discrepancies with hyperthreading CPUs.

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Interesting read here: http://www.forums.simflight.com/viewtopic.php?t=10437 I have a PIV2.53 w/o HT and the 9700 Pro and FS2k4 runs extremely well. Noticeably, much better than FS2k2 ever did with more visuals on the screen.PS: I'm also running a clean XPHome without SP1 or any other upgrades. Only patch I've applied is the Blaster Patch.

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Although techie the answer is quite simple Ken:As a result of the HT processor identification support, the following HT-aware features are included in Windows XP and the Windows Server 2003 family.

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>I assume everyone knows that you must be running Windows>>2000 or XP to take advantage of Hyperthreading. Win9x and ME>>don't support multiple processors. >>Unfortunately Windows 2000 does NOT support HT correctly--it>does however support multiple processors. HT is the ONLY>reason I would move from Win2K Pro to XP.>>NoelHiI recentely upgrade my computer to a Intel P4 3.06 (HT). I do not start over o new win XP PRO instalation and the system detect the new 2 processors but the HAL do not. I get the follow information:If anyone still cares...The system most most likely recognize the second processor. The system will most likely not utilize it because hal HAL is based on a APCI Uniprocessor, not an ACPI multiprocessor. You can look at the "Computer" type in Device Manager and you'll see what I mean. Under the processors section you'll see that Windows has recognized the second processor. You can also look at the Task Manager under the performance tab to see if you have two processors being utilized. If you have two separate windows monitoring CPU usage, then you're using both, otherwise you're not. At this point you probably need to reload Windows to bring it in.For Win2k, you used to able to do this to invoke the second processor: refer to Q234558. At this point I'm researching how to manually update the HAL in XP as you could in 2000. -Neil HOW TO: Add Support for Multiple Processors in Windows 2000The information in this article applies to: Microsoft Windows 2000 Server Microsoft Windows 2000 Advanced Server Microsoft Windows 2000 ProfessionalThis article was previously published under Q234558 IN THIS TASK SUMMARY Installing Support for Multiple CPUs REFERENCESSUMMARYWindows 2000 provides support for single or multiple Central Processing Units (CPU); however, if you originally installed Windows 2000 on a computer with a single CPU, the hardware abstraction layer (HAL) on your computer must be updated for your computer to recognize and use multiple CPUs. This article describes how to add support for multiple processors in Windows 2000. In Microsoft Windows NT 4.0, you can use the Uptomp.exe tool to add support for multiple CPUs. The Uptomp.exe tool is not used in Windows 2000, instead, you can use Device Manager to make these changes. Note that before you change the computer type, contact your computer manufacturer to determine if there is a vendor-specific HAL that you should use instead of the standard HAL that is included in Windows 2000. back to the top Installing Support for Multiple CPUs1. Click Start, point to Settings, point to Control Panel, and then click System. 2. Click the Hardware tab, and then click Device Manager. 3. Double-click to expand the Computer branch. Note the type of support that you currently have. 4. Double-click the computer type that is listed under the Computer branch, click the Drivers tab, click Update Driver, and then click Next. 5. Click Display a list of known drivers for this device, and then click Show all hardware of this device class. 6. Click the appropriate computer type (do not change from non-ACPI to ACPI computer types), click Next, and then click Finish.The following table lists and describes each HAL. HAL Description---------------------------------------------------------------------------ACPI MultiProc Use for a multiple-processor ACPI computer ACPI UniProc Use for a ACPI multiple-processor board but with a single processor installed Advanced Use for a single processor motherboard with singleConfiguration processor ACPI computerPower Interface PC Compaq Systempro Use for a Compaq Systempro computer MPS Uniprocessor PC Use on non-ACPI computers dual processor motherboard with a single processor installed MPS Multiproc PC Non-ACPI computers with a dual processor running Standard PC Any Standard PC, non-ACPI, or non-MPS. Could be a 386, 486, Pentium, Pentium II, or Pentium III Standard PC with C-Step i486 NOTE: You can use this procedure only to upgrade from a single-processor HAL to a multiple-processor HAL. If you use this procedure to change from a standard HAL to an ACPI HAL (for example, after a BIOS upgrade) or vice-versa, unexpected results may occur, including an inability to boot the computer. back to the top REFERENCESFor additional information how to troubleshoot Windows 2000 HAL issues, click the article number below to view the article in the Microsoft Knowledge Base: 237556 Troubleshooting Windows 2000 Hardware Abstraction Layer Issues back to the top Last Reviewed: 5/14/2003 Keywords: kbHardware kbhowto kbHOWTOmaster KB234558 kbAudITPro ANYBODY KNOWS NOW HOW CAN I CHANGE THE HAL TO DETECT CORRETELY THE NEW PROCESSOR? i CAN

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I contacted MS support as soon as I saw your message (Sunday, September 7). I got through in record time (Sunday morning must be a good time), talked with a rep in Nova Scotia who e-mailed me the fix while we were still on the phone. I was impressed!I will install the fix and report what I see later in the week.Thanks.

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Before I crack up over that user name, why not tell us what the fix involves instead of us having to wait. Or at least tell us were the fix is located. I find it strange that the fix was E-mailed to you. My question is, if it's an issue that needs a fix why is it not available on MS's site?ThanksBobby

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As to those great screenshots- I have a P4 3.06 533mhz, hyperthreading is enabled in the bios. I see exactly the same CPU usage (or lack thereof) as you show- the second CPU is hardly used while the first is cranking full steam. Very strange but I don't think we're the only ones... and I'm sure performance would get a big boost if both processors were working.Best,Joel

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