Reality Check: These FSX based sims are a breed apart from most games. In fact under the hood they are proper simulators and have professional intentions. So they have the option to assert affinity, so we can partition the machine. With most new games it doesn't matter much the way they are built makes it hard to apply affinity for example on Steam games as they are adjudicated from another process.

In the end with a games oriented PC we need 6 cores no HT and we get satisfactory results, most games will work better that way without technical intervention. In that way the popularity of overclocking on all cores has come about to overcome the problems of too much happening to do too little work making heavy work of light work needs the overclock. On these FSX based simulators we need only overclock one core or even the standard setup with turbo boost will suffice. Unless we want to squeeze a little more fps we can OC for a lift.

So for purely games stick to 4 or six core no HT and spend more on the GPU.

For PCs aimed at modeling and creativity or movie editing and so on, more cores are desirable so running games can be a problem, we can use an AM with these sims but for most games it's less of a concern.

7 hours ago, ZLA Steve said:

Did you run identical conditions? (weather, camera angle, time of day, AI, etc...) Dawn/Dusk rendering is the most demanding time for graphics as the shadows and lighting are constantly changing.

Yes - same exact. From what I am reading it sounds like I need to tweak AM. This is a new build/install so I have not completed all of the tweaks yet. I haven't touched the CFG at all actually. Installing over 50 add ons took some time!

7 hours ago, SteveW said:

When turning off HT improves the fps this shows that with HT enabled the first task was sharing. Naturally, turning off HT here would alleviate that condition in those cases Or even better, we supply an AM ending in  '01' which does the same thing without having to lose out on HT.

What about many cores, say 16 cores - do we need an AM there?

When we use no AM on many cores, like 10 or more we see another problem disabling HT cant help it, That is when any tiny bit of scenery is gathered, all the cores come to the fore when less than one core would do it. And in that case the CPU is saturated and causes a stutter. So we can use an AM there to stop that.

With tests on 18 core and 10 core 9900 class systems, using HT enabled and AM340 gives good results, that's only using four LPs. No AM is a disaster, HT on or off.

 

On a test harness - in the graphs below, same exact conditions each test:

Note that with no AM the CPU is maxing out all the time, than with AM340, on this six core with HT enabled. Giving the AM340 system overhead for more settings increases or a smoother ride:

 

So this comes up a lot and the eyes gloss over when reading about it.

 

 

 

 

This is very intriguing Steve. So I have a 9900k but run with HT off as I prefer a cooler running CPU. But you say running no AM with or without HT is not good on a high core system. You said AM340 with HT on for a 9900, what is a good AM for a 9900 with HT off? Thank you

Edited December 4, 20196 yr by B777ER

1 hour ago, SteveW said:

In fact under the hood they are proper simulators and have professional intentions. So they have the option to assert affinity, so we can partition the machine. With most new games it doesn't matter much the way they are built makes it hard to apply affinity for example on Steam games as they are adjudicated from another process.

Any Windows process can adjust its own affinity, and it can set the affinity for process or threads it launches. I'm not sure how using the Windows API makes one more or less professional - if anything, it says something about either the coding behind FSX/P3D or its users that we keep trying to tweak what the Windows scheduler can do for thousands of other professional applications without issue. 😉

Cheers!

Edited December 4, 20196 yr by Luke

spin.

For the 9900k try AM30 with HT off to start with.

Next question.... is anyone excited to not have to deal with the computer engineering insight needed for P3D when FS 2020 comes out?!?! haha.

How the new sim will behave and Luke playing with semantics doesn't change the reality of the situation with respect to the Impact of HT on vs Off to P3D.

On my machine Steve is correct. I can't speak for anyone else 😊

 

1 hour ago, SteveW said:

spin.

For the 9900k try AM30 with HT off to start with.

Copy, thanks Steve. This keep P3D on all cores with HT off?

Edited December 4, 20196 yr by B777ER

We are using the [JOBSCHEDULER] section in the cfg because otherwise we are saying AM=0 which means on a many cored system the tasks of P3D occupy more than necessary. Usually we would not need to worry about the AM, for example we want all cores in use when editing the movie. But P3D is a hybrid of a monolithic UI and rendering system coupled with a parallel back end. So we use the tool provided for the purpose. It takes a little thought. The main thing is, it's not absolutely necessary as I already say, but it can be used to extract a little more performance if it is possible to do so.

My comment about other games is not about their professionalism of the use of a Win API, but rather obviously it was about the way FSX and ESP were designed for more professional aspects of use. They provide the instruction for the Jobscheduler. The Jobscheduler is left to get on with that. We are only choosing to use less cores or LPs for a specially designed system that works well with it.

I have HT off no AM but all cores in use in P3Dv4,5.

In testing no AM in the config.

https://www.flickr.com/photos/154944674@N05/49166721741/in/dateposted-public/

https://www.flickr.com/photos/154944674@N05/49166722076/in/dateposted-public/

 

Edited December 4, 20196 yr by rjfry

1 hour ago, SteveW said:

My comment about other games is not about their professionalism of the use of a Win API, but rather obviously it was about the way FSX and ESP were designed for more professional aspects of use. They provide the instruction for the Jobscheduler. The Jobscheduler is left to get on with that. We are only choosing to use less cores or LPs for a specially designed system that works well with it.

And my point is that there is plenty of performance sensitive software out there with latency and throughput implications far in excess of FSX/P3D that doesn't need to override the OS scheduler. I suspect it was put in place as a debug tool or "because we can" tool for users and it's now reached almost mythical importance - which is odd because there are plenty of folks running with all sorts of Affinity masks (like Hyperthreading) and if I had to guess the real causes are totally different and merely getting exposed by different core usage. That smells like a lot of race conditions in the code and poor ways of debugging stutters.

My hope is that FS2020 if nothing else can provide error/debug logging to identify what parts of the sim are stalling, or far better eliminate them. It's sad when my warship games can give me rock-solid 77fps at 2560x1440 with stunning graphics.

Cheers!

16 minutes ago, rjfry said:

I have HT off no AM but all cores in use in P3Dv4,5.

7700k? That's right you wouldn't need to add anything since the jobscheduler has an AM of 15 and so no AM=0=15 which uses all cores '1111';

With HT enabled try 01,01,01,01 = 85 which uses all four cores. If some process doubles its count then you will see less performance with HT enabled, but not with P3D itself.

Mythical - again playing someone with semantics. It's a simple configuration, no more no less. Would be nice to be avoidable but with FSX and P3D on my systems they don't like no AM HT or not.

...thanks all for the support - appreciated.   What I'm really saying is that we can avoid a drop in performance inherent in HT and many-core, but we can't gain any.

With 4 or 6 cores no HT we let it rip, we can still look into exactly how it performs and on most six cores we see AM=30=011110 works exceedingly well. Again that's just four LPs.

Most games even they look great and run at 240 fps. But they are designed to a standard. P3D and FSX we can shove in what we want even if it brings it to its knees.

 

It's up to developers to make sure addons are built so as to not disturb that performance. If it does so, then they have a duty to provide settings for the user to put it into range of their horsepower.

 

Edited December 4, 20196 yr by SteveW