HT off saves VAS and increases fps ...

[GSalden 4,655]

Originally posted by Rob and continued at AS :

 

http://forum.aerosoft.com/index.php?/topic/100522-500mb-vas-reduction-and-increase-fps-by-22-in-v3/

 

What are your experiences ?

[Olmba 27]

HT off about 400 MB less vas usage.

[joemiller 269]

I'm very sorry to disappoint everyone but I am unable to confirm these claims.

 

Why?

 

 

 

 

 

 

 

Cause I don't have P3D V3

 

 

[swiesma 625]

HT off does not change anything for me.

Didn't put much time in investigating... But as I have no OOMs at all since V3, I will not spend any more time on this

 

Btw: No FPS gain whatsoever.

 

Processor: Intel i7 6700k @4,5 GHz with AF 84

[carlito777 712]

This has been discussed at length here already:

 

http://www.avsim.com/topic/476776-500mb-vas-reduction-and-increase-fps-by-22-in-v3-need-some-testers/

 

Is there really a need to discuss it all over again?

[SteveW 1,792]

Is there really a need to discuss it all over again?

Seems like it is. HT enabled with a suitable AM is the best performance. Comparing HT enabled with no AM against HT disabled is like comparing a petrol and diesel engine but when they can only use diesel fuel for the testing.

 

P3D and FSX run optimally on 4 separate logical processors. If we run P3D/FSX on an HT enabled processor with no Affinity Mask, the sim will spread across 8 processors instead of four (on a four core). Each thread a 32bit process makes on a 64bit O/S grabs a few extra Mb, so 8 processors = less VAS available.

 

What about the apparent improvement in fps? This can happen when an HT enabled processor stops and starts competing threads on the core running the main sim thread, and the in-sim counter shows higher fps. It's not higher fps overall.

 

Check out the light blue line shows fps-delta the true performance:

 

[Manny 1,293]

If you are using Photosceneries etc...then HT helps (with proper AM set). I can see each of the HT is working when I fly fast and low.... It rapidly builds my textures and It cures blurries.

 

I have reduced my OC from 4.5Ghz to 4.4Ghz so  I can have HT. 

[GSalden 4,655]

@Steve :

 

At Simmerhone.de there is an article at the FrontPage about HT and they also advice to modify a regoster setting so that no (virtual)cores are being parked.

This might stop stuttering..

 

http://simmershome.de/ht-optimal-nutzen/

 

At the Attributes entry 1 has to be set to 0.

 

What is your advice and this ?

And if you advice to do it can I leave my AM at 340 ?

 

Thanks,

Gerard

[SteveW 1,792]

Win10: HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Power\PowerSettings\54533251-82be-4824-96c1-47b60b740d00\0cc5b647-c1df-4637-891a-dec35c318583

 

Attributes=1 by default, instead set to 0 to ignore the core parking setting. This setting pecifies the minimum number of unparked cores/packages allowed for Processor Power Efficiency Class 1 (in percentage). ValueMax=100, ValueMin=0. Means it can park all cores when inactive.

 

I would leave it alone, since when the sim is running you'll not have any idle cores. Leave your AM at 340.

 

...that's physical cores, meaning an HT core being two virtual cores. On or off won't affect the choice of AM.

[GSalden 4,655]

Many thanks Steve

[Mischung 48]

Thanks Steve for your posts! Makes it very clear.

 

I have also very good performance with 4 cores (HT=on) -> so logical 8 cores.

P3D may use all cores except on the main threads core where one LP is masked out, to avoid the competing 2 logical processes.

 

So the main thread must reside on one physical / two logical cores alone!

 

I also set an affinity for all other processes in the background (with Process Lasso) not using the main threads core at all.

[warbirds 555]

Looking at the graph it seems that 30 is best for 6 core? I am currently running 340.

[SteveW 1,792]

Thanks Steve for your posts! Makes it very clear.

 

I have also very good performance with 4 cores (HT=on) -> so logical 8 cores.

P3D may use all cores except on the main threads core where one LP is masked out, to avoid the competing 2 logical processes.

 

So the main thread must reside on one physical / two logical cores alone!

 

I also set an affinity for all other processes in the background (with Process Lasso) not using the main threads core at all.

Thanks Marc, sounds good.

 

 

Looking at the graph it seems that 30 is best for 6 core? I am currently running 340.

Paul, 340 is good for 6 core with HT enabled, but 30 is for 6 core with disabled HT.

 

 

A slight improvement to the fps-delta can be seen with the 6 core HT enabled AM=340 over the HT disabled AM=30. We get smoother operation with HT enabled since the time to swap threads is halved.

[jimh 23]

Hi,

 

I'm not very technical and am currently runnning without hyperthreading on my i7-4790k (4 cores)

 

I've monitored the load on eight logical cores when I did have HT enabled, with a view to deciding on a suitable AM, but the variation in load defeated me.

 

Is there a "best"  affinity mask for a four core running P3Dv3?

 

Marc seems to have a pretty comprehensive solution, also covering the background stuff which is very interesting.

 

Thanks, Jim

[Manny 1,293]

4 core no HT... AM = 15