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Hyper Threading & P3D V4?

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Hello! Would you recommend turning on or off hyper treading for P3d V4? I currently have a i7--4770K 3.5GHz.

Thoughts?

 

Thanks!

Clem

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I never turn HT off.

You can still turn thread cores off by affinity mask. But try it yourself on your system and with your addons/settings. 

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You should consider overclocking your CPU. Mine is running stable at 4,5 GHz, THAT will gain really more power.

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Hi guys, I just updated my new RiG i7-7700k with Maximus IX Code and will soon OC to 5.0Ghz (coming from AMD FX-4300 @ 4.6Ghz) any more idea about HT ON or OFF? do we need to set the AffinityMask? or better ask has any of you (testers) tested the new P3Dv4 any modifying the .cfg? 

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May I suggest you do a search of this forum for ---  Steve Waite Hyperthreading -- 

There have been quite a few definitive posts on this subject that will prove helpful.  Might get you more information than the simple "should I enable HT or not?"

 

Vic

 

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What JoeFackel said.

Mine; i7-6700K CPU @ OC 4.60GHz, HT off = great performance.

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I run P3Dv4 'out of the box'. No tweaks what so ever and it runs great. Why should I spend hours to go from 30 fps to 35 fps ?

Less time tweaking = more time flying

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44 minutes ago, vgbaron said:

May I suggest you do a search of this forum for ---  Steve Waite Hyperthreading -- 

There have been quite a few definitive posts on this subject that will prove helpful.  Might get you more information than the simple "should I enable HT or not?"

 

Vic

 

I believe that this does bear some further discussion.  Personally, I've not seen a discussion of hyperthreading that specifically addresses the new 64-bit P3D v4, and I'm not at all confident that the previous discussions as they pertained to v3 and earlier 32-bit fare are relevant to a discussion of the new sim.  .

Regards

 

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4 minutes ago, w6kd said:

I'm not at all confident that the previous discussions as they pertained to v3 and earlier 32-bit fare are relevant to a discussion of the new sim.

Exactly!

I have found that all 8 of my cores are being utilized under v4.

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Steve Waite did a very in-depth analysis of performance, specifically frame rates and long-frame events, with respect to HT in P3Dv3.  There, we also saw activity on all of the virtual CPUs, but it turned out that it did not enhance the sim's performance at all, as the processes were just being rapidly shuffled back and forth between vCPUs rather than actually doing any meaningful concurrent processing.  So I think the presence of activity on the vCPUs, by itself, is a potential red herring absent some more complete analysis of how that actually affects performance, as Steve did before.

But that said, there's the real possibility that the rewrite that was done for 64-bit in order to compile it with 64-bit code might--might--also incorporate some optimizations that actually utilize HT on the modern CPUs the 64-bit development environment was created for.

Cheers

 

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I have full utilization of my 8 CPU cores too.  I am totally against the Affinity Mask tweak unless you have a system prior to Sandy Bridge (i7 2600K).  Personally I am seeing fantastic performance with my sytem.  Even if the fps get into the 20's I have smooth image processing.  I do see some problems occasionally in the rendering of images with MSE Florida around the Miami area (have LatinVFR KMIA and FSDT KFLL - Lauderdale) and FPS are in the 60's and 70's.  I've gotten it a bit better by lowering my settings a little.  I do not look for perfection though so I may be a bit biased.  I hope though that no one tries to use the Affinity Mask tweak on P3Dv4.

Best regards,

Jim

Edited by Jim Young

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17 minutes ago, w6kd said:

....  So I think the presence of activity on the vCPUs, by itself, is a potential red herring absent some more complete analysis of how that actually affects performance, as Steve did before.

But that said, there's the real possibility that the rewrite that was done for 64-bit in order to compile it with 64-bit code might--might--also incorporate some optimizations that actually utilize HT on the modern CPUs the 64-bit development environment was created for.

Cheers

 

Right on!

All these "it utilizes all my cores" claims do not further our understanding of what benefits we might get (or not) from having mores cores available to P3DV4.

The saying "too many cooks in the kitchen" comes to mind..

I wonder why LM does not contribute more to this discussion.. I would think that their development team would have some insight as to what the P3D engine does or does not benefit from in terms of resources.

I am personally running P3DV4 on a quad Haswell CPU with HT off and no affinity mask, and am seeing great and consistent performance.  Just observing the task manager graphs, P3D is distributing workload a bit differently than FSX.  FSX has a clear, single core at 100% and the remaining cores varying, based on scenery loading and re-lighting requirements.

P3D on my system has one core heavily used at all times (although not at 100%), a second "helper core" doing whatever it is doing, and the remaining cores varying based on scenery loading requirements.. no regular lighting cycle that I can see.

As stated above, I would welcome some contribution to this discussion by the LM development team  :cool:

 

Now, would it be good to have some as yet unused cores available for addon apps that could be directed to them... entirely possible..

 

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Actually, guys, Steve Waite has posted extensively on hyperthreading and affinity mask in P3D4.  Have a look at this long thread.  It's worth reading all his posts, and the links to his own site, but his shorthand recommendations for affinity mask settings are in this post.

I'm currently experimenting with some of these settings, and with the use of batch files to assign affinity masks to add-ons, in a mostly vanilla P3D4 installation ("mostly" because it's got FSUIPC on board, but nothing else yet).  Can't say anything definitive about performance impact, and at the moment I'm trying to trace the cause of a hard freeze that might be the result of affinity mask use, or of insufficient voltage, or (my guess) a driver conflict.  So this isn't a recommendation.  But as others have noted, Steve knows his stuff, so I'd say his P3D4 material is worth reading.

 

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I'm another that tried the affinity mask thing, but went back in the end due to no real gains.. the best setting for my 3930K hex-core is no affinity mask and hyper-threading off. HT off has made my sim super smooth and i believe Rob Ainscough runs his 5960x 8-core in exactly the same way.

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22 minutes ago, stripealipe said:

I'm another that tried the affinity mask thing, but went back in the end due to no real gains..

I may wind up there.  My hard freeze issue seems to be voltage-related, but I'm going to run some additional tests and see how the system performs with HT off/no affinity - and, maybe best case, if I can drop voltage back down with HT disabled.  Would prefer to fuss less and fly more.

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And an update... in my latest test, I was able to keep my 7700k stable at 5.0 GHz and 1.30 vcore with no affinity mask and hyperthreading off.  In the previous test, it took 1.325 vcore to maintain stability with affinity mask = 245 in P3D4, and TrackIR 5 running on the last two cores via a batch file per Steve's recommendations.  I couldn't see any performance loss with hyperthreading off.  And in AIDA64, my temps are about 8 degrees C lower at the lower vcore.  So... based on all that, I'm inclined to go without hyperthreading and affinity masks.  Again, this is early days, and I'm not really stressing P3D4 yet - no payware aircraft or airports, no AS16.  So don't take it as definitive - just one set of results to work with as you try to figure all this out.  Hope it's helpful.

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3 hours ago, Jim Young said:

I am totally against the Affinity Mask tweak unless you have a system prior to Sandy Bridge (i7 2600K).

 

Actually, my Skylake 6700k (4 cores, HT on, OC 4.5 Ghz) runs best (meaning, no noticeable stutters or long frames) with Affinity Mask=245 or 85; by contrast, with default setting (i.e. no affinity mask in cfg) I experienced fairly significant stutters.  This is quite reproducible on my system.

Whether or not one needs to use the affinity mask setting is highly dependent on one's specific hardware and software environment.  On my system, allowing P3D to run with two threads simultaneously on cores 0 and 1 while also hyper-threading does not work well, and the observations are consistent with what was discussed in the reference thread posted by Alan. I choose to keep hyper-threading on because my sim computer is also used for other applications where HT is a clear benefit.

 

 

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That's great!  Glad it works for you.  It does not for me.  I see no stuttering, long pauses with HT on.  No tweaks.  But I have a 7700K.  I have most of my settings set to max and have no problems whatsoever with stutters but then I have a more powerful CPU and MB and GPU.

I have no concern with experienced persons like you using the tweak or any tweak but we have a lot of members who are not that familiar with computers and will add a tweak just because someone else has a tweak and the tweak settings are much different on their system than others.  They then have unexplained crashes and other anomalies. 

Personally I will not use the tweak as I have seen too many issues with it over the years. 

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Haven't read all posts so sorry if repeating but my suggestion would be :

Disable HT to allow your CPU to run cooler meaning you'll be able to overclock it higher at lower voltage and stay away from any tweaks including AM tweaks.

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HT on AM=245 with VSYNC and unlimited smooth as silk :cool:

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Have a look at this discussion, I show how v4 utilises six LPs to split out the rendering section leanest with only four cores:

So if we only have four cores available 245 unmasks six logical processors and allows the sim to split out its parts to the leanest rendering. Also since we only have four cores those doubled up jobs show how HT enabled provides the mechanism to improve on maximum core throughput.

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Like saying we need not worry about checking the oil, especially if we fly faster. If we give P3D a rubbish AM it will actually still work OK, any problems reported will be from other finger trouble.

HT and AM - these minor technical details are a necessary evil right now especially with many-core CPUs arriving. Most of us want a good P3D PC and we won't be pushing frequency limits. If it has an overclock then it will be moderated to accommodate HT which will more than regain the lost cycles to a few MHz. Eight core is becoming abundant, six core can OC higher, but they still only use two cores for rendering

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could you suggest between AM=250 and 254 on quadcore with HT on. The light second rendering task is shared with a fifth loading task on a core with its two LPs in the latter. Can that improve the throughput or better to stick with 250?

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Speaking of new multi-cores CPUs coming I watched this clip on YouTube yesterday.

I don't know anything about this guy but what he says in this video will at least make me think twice about upgrading my current 6600K.

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I am running my 6700K@4.3, HT on, no AF -> runs perfect.

I get stutterts with any AFmask setting.

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