Use all cores

[dEhiN]

I was reading in another thread that Dolphin is a dual-core application. Is this still true of the current release - 3.5? My settings are Enable Dual Core, No Lock Threads to Cores, DSP HLE Emulation, OpenMP Texture Decoder. I thought that the last setting - OpenMP - would allow Dolphin to utilize all 6 cores since the setting is described as "Use multiple threads to decode textures". Is there a way to get Dolphin to use all 6 cores for CPU emulation (and maybe GPU emulation as well)? Thanks for the help.

[admin89]

The OpenMP does speed up some games but the difference in speed is very small and may be not noticable
The most major thing that OpenMP do is to reduce micro-stuttering

Quote:Is there a way to get Dolphin to use all 6 cores for CPU emulation

Not impossible but ... I'm lazy to explain so please read :
http://dolphin-emu.org/docs/faq/#couldnt-dolphin-use-more-my-cpu-cores-go-faster
You should give up on that idea and overclock your CPU or move on the better CPU (better IPC performance , better single-thread performance)
Even if Dolphin used all cores , your GPU would bottleneck the whole system

[rpglord]

Actually, dolphin do use all available cores, it can easily be checked in task manager.
Its just that important threads are only on 2 cores ( 3 if you enable LLE on thread and use LLE )
Dolphin uses only 1 core for cpu emulation, and one for gpu.

[Yottabyte]

Why don't use Lock Threads to Cores?

[Shonumi]

People shouldn't get confused between the number of cores active while running Dolphin and the actual number of major threads Dolphin uses. Like rpglord said, Dolphin will use at most 3 major threads to do the majority of its processing. One thread handles emulation of the GC/Wii CPU, GPU, and DSP. Note, since the New AX HLE merge, the DSP gets a major thread on HLE just like LLE + LLE on threads.

Dolphin has a number of minor threads for things like input and handling the GUI, but in reality they end up doing far less than what the major threads do. With options like OpenMP it is possible to see more than 3 cores active while running Dolphin. But only 3 threads at most are driving most of Dolphin's performance.

Also, be careful with the Windows task manager rpglord, when measuring how many cores are active. Due to how many versions of Windows handle their scheduling, it may look like all cores are in use, but actually something else is happening. Dolphin's threads tend to jump across cores faster than Windows can report, so in between one reporting interval, Dolphin's threads will have done some processing on a number of different cores (not simultaneously however). Lock Threads to Cores will correct this. We get a number of people with i7s wondering why all 8 of their cores are active but at like 20% or something because of this misconception :p

[LordVador]

(01-07-2013, 02:58 AM)Yottabyte Wrote: Why don't use Lock Threads to Cores?

This would lock threads to 2 cores (or 3). This isn't what he's been trying to get

[dEhiN]

So in summary, Dolphin will potentially utilize all 6 cores to run its 3 major threads (+ any minor threads) but not necessarily simultaneously? Does anyone know if the Lock Threads to Cores option gives a significant speed boost or decrease? I don't rely on Windows Task Manager, but run a Win7 gagdet that reports how many cores are working, at what percentage, and the overall cpu percentage. I did notice with the Lock Threads option that 2 cores were steadily reporting 100% usage with Dolphin running a game. When the Lock Threads option is not checked, all the cores fluctuate from about 10-25% (roughly from what I remember). In both cases though the overall cpu usage was about the same (don't remember the percentage amount now).

[Shonumi]

(01-07-2013, 05:57 AM)dEhiN Wrote: So in summary, Dolphin will potentially utilize all 6 cores to run its 3 major threads (+ any minor threads) but not necessarily simultaneously?

Yes when we're talking just about the major threads; the minor threads (there are a lot, actually) could collectively spread to all of the available cores, they just won't amount to a whole lot of processing. Nothing (aside from OS scheduling or Lock Threads to Cores) prevents the 3 major threads from jumping to all of your system's cores. On quad-core+ systems, the threads just can't be on all of them simultaneously, e.g. the 3 major threads can't be on all six cores at the same time in your case. If your system only has three cores, it is possible to have Dolphin use all the cores on your system, of course

(01-07-2013, 05:57 AM)dEhiN Wrote: Does anyone know if the Lock Threads to Cores option gives a significant speed boost or decrease?

This is usually useful for laptops that need to Turbo Boost. Desktops shouldn't really see any performance increase (or decrease?).

(01-07-2013, 05:57 AM)dEhiN Wrote: I don't rely on Windows Task Manager, but run a Win7 gagdet that reports how many cores are working, at what percentage, and the overall cpu percentage. I did notice with the Lock Threads option that 2 cores were steadily reporting 100% usage with Dolphin running a game. When the Lock Threads option is not checked, all the cores fluctuate from about 10-25% (roughly from what I remember). In both cases though the overall cpu usage was about the same (don't remember the percentage amount now).

I'm willing to bet that whatever tool you're using to monitor your CPU usage, it probably gets its info from the same source that Windows Task Manager would (the Windows kernel), so the results should roughly look the same (might vary depending on how it presents that data). Anyway, the overall CPU usage should remain the same with Lock Threads to Cores on and off, it's just a matter of having the threads stay on specific cores as opposed to jumping all over the place.