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Squadcast Summary (2015-05-30) - Mu Joins In!


BudgetHedgehog
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Given the way Mike phrased things, it sounds rather like some of the stuff Claw and I were discussing in the Overhauls thread, i.e. 1.0 levels of drag for spaceplanes and very-tapered rockets, and 1.0.2 levels of drag for pods.

We'll just have to see, though! :)

Oh! I'd be so happy if that's what's going to happen! Shuttle Orbiters gliding back home, heck yes!

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Skydiving related coccyx fracture! :(

Oh holy hell, that is miserable. I've done exactly that and felt the effects for months afterward. And doctors can't do a single damn thing to help.

Sorry, dude.

(But at least you all got to skydive!)

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It was in the context of thermodynamics, as in they're fixed for the changes to the heating system.

Quoting this since people still haven't caught on.

Fairings fixed with regards to thermodynamics, not related to any other issue

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Could somebody more tech-savvy than me explain what "multithreaded physics" means? :blush:

Currently KSP uses one thread (= roughly "one cpu core") to calculate physics. So if you've got a quadcore cpu 3/4 of it will stay idle. Even if that one cpu core is running at 100%.

The new Unity engine will allow to use more than one thread for physics. So we should see a performance increase. (Hopefully a big one but I'm not sure.)

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1.0.3 news! Mu's been putting hours into it, he noticed even before 1.0 that balancing heating for command pods and cockpits is mutually exclusive, so they're introducing a new heating system called Skin Heating - basically, rather than seeing a part as a part, you see it as things surrounded by a shell of metal that heats up and cools down quicker - this basically makes things easier to balance overall.

Can anybody explain what this means for gameplay? I'm having a hard time understanding it.

Currently KSP uses one thread (= roughly "one cpu core") to calculate physics. So if you've got a quadcore cpu 3/4 of it will stay idle. Even if that one cpu core is running at 100%.

The new Unity engine will allow to use more than one thread for physics. So we should see a performance increase. (Hopefully a big one but I'm not sure.)

Most likely it will only mean a performance increase for multiple craft in physics range.

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They (we) want 2 piece fairing separation, which is more realistic. Right now fairings can eject as many as 50 or more pieces using the 3.75m fairings.

Not only - They're rather buggy currently.

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Can anybody explain what this means for gameplay? I'm having a hard time understanding it.

Most likely it will only mean a performance increase for multiple craft in physics range.

If there is an increase in performance with more than one craft then it stands to reason that there will be an increase with one craft. Personally I cannot wait for this. But I remain sceptical as to how much of an increase we will see.

- - - Updated - - -

Quoting this since people still haven't caught on.

Fairings fixed with regards to thermodynamics, not related to any other issue

Have they said anything about when they will actually properly fix them?

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If there is an increase in performance with more than one craft then it stands to reason that there will be an increase with one craft.

That's not how multi-threading ships works.

Each ship will take its own thread. The ships will still have the same performance impact that they did before, but now it's spread between different cores rather than stuffed into a single one.

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Have they said anything about when they will actually properly fix them?

Thermodynamics? It has been fixed, according to Squadcast. Should be out in 1.0.3.

Exploding fairings? They didn't say they're gonna "fix" it.

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Self-quoting a well written post/link:

Eric S wrote a great post explaining that multithreaded physics will help...

What some call a complete fix for fairings - is a style preference. Their first priority is clearly on any aero/heating problems with them, fingers crossed that the style preference gets bundled along with it. For now, we have mod tweaks like the one in Claw's excellent package.

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That's not how multi-threading ships works.

Each ship will take its own thread. The ships will still have the same performance impact that they did before, but now it's spread between different cores rather than stuffed into a single one.

Er... What? Who said anything about unity 5 multithreaded physics only applying one core to each ship? That makes no sense to me whatsoever and I am sure it's simply not true. Multithreaded physics will apply to all ships simultaneously.

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Er... What? Who said anything about unity 5 multithreaded physics only applying one core to each ship? That makes no sense to me whatsoever and I am sure it's simply not true. Multithreaded physics will apply to all ships simultaneously.
Eric S wrote a great post explaining that multithreaded physics will help, but if you're looking for high FPS with 1000 part craft... it may not help much, if each craft must be in its own thread.

From what is being said, Unity 5 still can't seperate an object built out of other objects into multiple threads.

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So we might have a steady fps when our 500 part ship is 10 meters away from, and about to dock with, a 500 part station, but the 1000 part ship/station combo would still bog it down?

edit: not trying to sound ungrateful lol, just trying to see what we can expect.

Edited by r4pt0r
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So we might have a steady fps when our 500 part ship is 10 meters away from, and about to dock with, a 500 part station, but the 1000 part ship/station combo would still bog it down?

I'd say even one 500 part ship is too much for KSP :wink:

But think about it this way: parts on the same ship (the same object) are applying forces to each other all the time. Parts on two different ships don't do that nearly as often (only when crashing into each other or blowing it away with an engine).

So, while the interactions between two ships are limited and splitting them into two threads sounds doable, you would have to do constant thread sync if running multiple threads on one ship. And thread syncs/communications are expensive. So expensive, that multiple threads running one ship would most probably lower performance compared to a single one.

In short: yes, multiple ships close together will run a little smoother, but the highest part count of any of them is still the limiting factor. So, yes, two 500 parts ships will cripple performance, while the 1000 parts ship after docking will obliterate it. However, 5 100 parts ships will most probably run faster than now.

disclaimer: just applying basic programming knowledge, I have no idea what tricks and simplifications the Unity devs applied.

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From what is being said, Unity 5 still can't seperate an object built out of other objects into multiple threads.

Considering two craft are rarely, if ever flown together it would be moot for Squad to even suggest that the change to unity 5 would result in performance increases..

- - - Updated - - -

I'd say even one 500 part ship is too much for KSP.

It wasn't for KSP version 0.90.. Performance at present is unacceptably low. I dearly hope Unity 5 pushes it past were we where in version 0.90.

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They (we) want 2 piece fairing separation, which is more realistic. Right now fairings can eject as many as 50 or more pieces using the 3.75m fairings.

Personally I like the explosion style fairings, although I certainly understand why people would hate them.

Er... What? Who said anything about unity 5 multithreaded physics only applying one core to each ship? That makes no sense to me whatsoever and I am sure it's simply not true. Multithreaded physics will apply to all ships simultaneously.

One thread does NOT equal one core.

Each core consists of a number of threads.

KSP is and has always been multithreaded (but uses a single core). The physics engine is only single threaded, but it so far dominates the other threads in terms of required processing power that KSP might as well be single threaded.

Take the i3 processor for example. It has two cores. Each core has two threads. So the Physics engine can use (about) one quarter of the i3's processing power. With Unity 5, the Physics engine will be able to use at least an entire core (I'm not sure on the exact details) so it would use at least half, with the rest of the game (and most likely everything else) running on a different core. More advanced processors have either more cores, more threads per core, or both. Less advanced processor would have fewer (currently allowing KSP to use more of their processing power) but are less powerful overall.

EDIT: 200 posts!!!

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Personally I like the explosion style fairings, although I certainly understand why people would hate them.

One thread does NOT equal one core.

Each core consists of a number of threads.

KSP is and has always been multithreaded (but uses a single core). The physics engine is only single threaded, but it so far dominates the other threads in terms of required processing power that KSP might as well be single threaded.

Take the i3 processor for example. It has two cores. Each core has two threads. So the Physics engine can use (about) one quarter of the i3's processing power. With Unity 5, the Physics engine will be able to use at least an entire core (I'm not sure on the exact details) so it would use at least half, with the rest of the game (and most likely everything else) running on a different core. More advanced processors have either more cores, more threads per core, or both. Less advanced processor would have fewer (currently allowing KSP to use more of their processing power) but are less powerful overall.

EDIT: 200 posts!!!

Lol, thanks for the lesson but I am aware of all those facts.

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KSP is and has always been multithreaded (but uses a single core).

If KSP is limited to use one core (affinity) it performs worse than when it is allowed to use multiple (two) cores.

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Considering two craft are rarely, if ever flown together it would be moot for Squad to even suggest that the change to unity 5 would result in performance increases..

The U5 physics benchmarks I've read about show significant performance improvements even when single-threaded, sometimes as much as 30%. I'm expecting to see a modest performance increase for single craft and a bigger jump for multiple craft in physics range.

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