(quad-core i7)
Hyperthreading?
Is this a problem, does it slow the emulator down?
Hyperthreading?
Is this a problem, does it slow the emulator down?
Why's Dolphin say I have 16 cores?
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12-05-2010, 01:41 AM
(quad-core i7)
Hyperthreading? Is this a problem, does it slow the emulator down? 12-05-2010, 01:42 AM
It says this to mine too.
That's a bug in Dolphin since a Core i7 with Hyperthreading has 8 Threads. (12-05-2010, 01:42 AM)Anti-Ultimate Wrote: It says this to mine too. Is the bug cosmetic or does this make Dolphin go slower? (Does Hyperthreading make it not use 2 full cores?) I turn off frame limiting, Dolphin is still only using 25% CPU Power. Dual-Core is on. 12-05-2010, 03:45 AM
12-05-2010, 06:26 AM
What does "lock threads to cores" even do? And why would having HT enabled with that cause slowdown?
Core i7 920 @ 3.6GHz
6GB DDR3 1333 EVGA GeForce GTX 460 SuperClocked 1024MB EE Windows 7 64bit 12-05-2010, 07:41 AM
Basically "lock threads to cores" gives Dolphin two exclusive cores, so the rest of your apps can use other cores. I guess that enabling HT won't let you assign exclusive cores, therefore Dolphin (being a cpu hog), may slow down if it's sharing cores with other apps.
Rig *Corei5 3570K *Nvidia 9800GT 1GB DDR3 *Motherboard Asus P8H77M-PRO *Win7 x64 *RAM 8GB DDR3(1600) 12-05-2010, 07:51 AM
Dolphin has two threads (it uses 2 cores). One for cpu emulation and the other for gpu/dsp emulation. Normally these threads jump around from 1 core to another every couple nanoseconds. So for example if you have a core 2 quad like me with 4 physical cores and you open task manager you will see 4 cores at 50% load instead of 2 cores at 100% load and the other 2 at 0% since the threads are jumping around. If I turn on lock threads to cores it will lock the threads to a specific core so that they can't switch over to a different core. So then in task manager I will see 2 cores at 100% load and the other 2 at 0% since dolphin is only using 2 cores. With HT you still have only 4 physical cores but each core tricks the OS into thinking it is 2 cores, called logical cores. If you lock threads to cores with HT on dolphin will use the first two cores available just like with any other cpu. However these two cores are logical cores that actually both belong to the same real physical core so you are actually only using 1 physical core, thus the slowdown.
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-Ron Swanson "I shall be a good politician, even if it kills me. Or if it kills anyone else for that matter. " -Mark Antony 12-05-2010, 07:58 AM
(This post was last modified: 12-05-2010, 08:51 AM by Xtreme2damax.)
Because then Dolphin locks to one of virtual cores (thread) and one physical core, locking threads to cores is bad for any hyper-threaded processor and will decrease performance.
12-06-2010, 07:00 AM
Dolphin's only using about 50% of 4/8 HT cores (that's what it looks like), giving 25% total CPU usage. What gives?
Dual-Core in on, Lock Threads off, DSPLLE on Thread off, SVN 6441 SSE4.2 64-bit. |
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