Hyperthreading

Tips and advice for getting the most from Scope. No questions here please.
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krizrox
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Hyperthreading

Post by krizrox » Sun Feb 01, 2015 9:19 am

All signs point to disabling hyperthreading in the the BIOS. But in my case, the option to enable or disable it was greyed out entirely.

After looking at the CPU specs, the Intel processor I bought doesn't seem to support hyperthreading. Is that good or bad? Did I choose the right CPU or is that actually a bad thing? I only care as far as DAW work and recording is concerned. I don't use my studio PC for anything else. If NOT having a hyperthreading enabled CPU works in my favor then cool. If it's a possible problem I'd like to know about it. What does it mean to have a 4 core CPU that doesn't support hyperthreading?

i5-4690K (LGA1150) CPU 3.5GHz 6MB cache

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garyb
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Re: Hyperthreading

Post by garyb » Sun Feb 01, 2015 9:35 am

hyperthreading involves virtual CPU cores to aid in certain types of off-line calculations. it takes a real core to do calculations for a virtual core, however. this makes hyperthreading useless or even a hinderance for Scope's real-time activities, anyway.

Eanna
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Re: Hyperthreading

Post by Eanna » Sun Feb 01, 2015 6:10 pm

Going off cpubenchmark.net, your choice of processor is the fastest available i5 on the market... So you can expect a happy computing experience for the next good while - hyperthreading or not :-)

What GaryB says is spot on - only highly-threaded applications can reap the benefits of Hyperthreading.
The way I understand this, Scope.exe and its libraries are not highly-threaded - Scope.exe, displaying it's GUI, and running a project containing ASIO and Midi I/O, shows only four threads running on my system, as you can see from the ProcessExplorer dialog for Scope.exe below. It appears that Scope.exe's four threads may all run on one core by Processor Affinity / Ideal Processor indicators, even here on Win7 32-bit on a four-core Xeon CPU.
However, a browser, for example, will have many times more threads... and so, you would expect would benefit from hyperthreading technology in the processor.

So, like GaryB says, having no hyperthreading at the CPU is only a good thing for something like Scope. That's because its the SHARC chips in your Xite that's doing the parallel calculation-centric heavy lifting, not your CPU. It's also why older Pentiums, running older flavours of Windows, with none of the modern multi-core / hyperthreading support in the Kernel or at the hardware level, can run Scope OK, but would choke on something like a browser...

Indeed, it may be easier for the Windows Kernel Scheduler to schedule a lightly-threaded process, handling asynchronous I/O on IRQs, and where I/O Queues, Memory access (DMA) and Synchronization are implemented at the driver level....

All of which allow Scope keep it's Real-Time promise on Windows.

And that's why Scope is cool :-)
ScopeThreads.png
ScopeThreads.png (63.74 KiB) Viewed 1634 times
Not because it is easy, but because it is hard...

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krizrox
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Re: Hyperthreading

Post by krizrox » Mon Feb 02, 2015 4:48 am

Wow thanks for the in-depth explanation guys! I really appreciate the responses. I learned something in the process.

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