Well, I know which is which because you've already said that it's best without an affinity mask
At least you know you've got nothing to gain by adding one! Result!
Ben wrote:Its also worth mentioning that depending on which post you read on which forum, FSX / P3D can only use physical cores so the hyper threaded ones don't count (I don't have any HT ones )
I wouldn't have posted it if I thought it was idle conjecture (oh, alright, I
might have done
). This was actually a thread on the official Prepar3d forum by a Lockheed Martin Prepar3d software engineer so I thought it might be of interest
I think he was breaking the news that, although it was intended for v2.0, it's already active now but nobody knew. He says here that P3D will select alternate hyperthreaded cores by default but he recommends using the affinity mask to reserve core one for the OS.
Zach Heylmun, Prepar3d Software Engineer wrote:Prepar3d 2.0 is targeted at improving performance. We are working to take better advantage of multi-core processors by threading off more of the computation to background threads. That being said, prepar3d 1.3 is actually able to use hyperthreading today. By default, Prepar3d will usually only use every other core on a hyperthreaded processor ( i.e. one thread per physical core ). This is the desired behavior because most of the tasks offloaded to background threads are related to I/O, and hyperthreading does not perform well when both threads are waiting on I/O tasks.
And to prove it, here's my CPU resource manager showing hyperthreading being used in P3D with the affinity mask set to 84. (I'm back home now
)
Main core 1 (CPUs 0 and 1), reserved for the OS, has one thread working and one parked. The other three main cores have one thread on each core working (in P3D) and one thread on each core idle. Which is what Zach says is the desired behaviour and what is also illustrated on his post. So, I dunno. It does work but if you haven't got hyperthreading then I guess it can't work on yours, Ben.
I bet I can guess what's top of your christmas list
Ian