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Cr0t l33t
Joined: 27 Apr 2002 Posts: 944 Location: USA
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Posted: Fri May 03, 2013 6:16 pm Post subject: SMT (Hyperthreading) and/or Multi-core scheduler support |
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The kernel has an option for "SMT (Hyperthreading) scheduler support" and "Multi-core scheduler support". If you have a system with HT and physical cpus, do you select both?
I have been just selecting multi-core scheduler and all the cpus are being used and show up for that matter.
Any reason why SMT is still listed since multi-core finds the HT cpus as well? _________________ cya |
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Gusar Advocate
Joined: 09 Apr 2005 Posts: 2665 Location: Slovenia
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Posted: Fri May 03, 2013 8:49 pm Post subject: |
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You should use SMT. Yeah, multi-core will work too, sorta, but the kernel will think all cores are equal. The cores are not equal with hyperthreading though, and SMT will make the kernel aware of that.
If you select both, the kernel will use SMT if it sees the machine has hyperthreading, and multi-core otherwise. It will not use both. |
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_______0 Guru
Joined: 15 Oct 2012 Posts: 521
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Posted: Sat May 04, 2013 12:35 pm Post subject: wrong answer! |
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the answer is in the help tab. Hyperthreading is, exclusively, for pentium4s, the other for the rest. |
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Gusar Advocate
Joined: 09 Apr 2005 Posts: 2665 Location: Slovenia
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Posted: Sat May 04, 2013 1:15 pm Post subject: Re: wrong answer! |
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_______0 wrote: | the answer is in the help tab. Hyperthreading is, exclusively, for pentium4s, the other for the rest. |
Incorrect. Pentium 4 was the first processor that had hyperthreading, but Core i3/5/7 processors have it too. |
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nlsa8z6zoz7lyih3ap Guru
Joined: 25 Sep 2007 Posts: 388 Location: Canada
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Posted: Sat May 04, 2013 3:08 pm Post subject: |
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Where does the amd fx-8350 fit into this? |
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_______0 Guru
Joined: 15 Oct 2012 Posts: 521
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Posted: Sat May 04, 2013 3:45 pm Post subject: |
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I wasn't talking about hypeardthreading in cpus but at to which cpu that option applies to.
[ ] SMT (Hyperthreading) scheduler support
Code: | SMT scheduler support improves the CPU scheduler's decision making
when dealing with Intel Pentium 4 chips with HyperThreading at a
cost of slightly increased overhead in some places. If unsure say
N here. |
So for AMD the second one:
[*] Multi-core scheduler support |
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Hu Moderator
Joined: 06 Mar 2007 Posts: 21633
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Posted: Sat May 04, 2013 4:46 pm Post subject: |
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Kernel help text, although useful, is sometimes out of date. Do you have a more definitive reference for that feature applying only on Pentium4 chips? I see nothing in the kernel source for SMT handling that appears to restrict it to Pentium4 chips. |
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