Logical processors

  • Igor Micev

    SSC-Dedicated

    Points: 33109

    Comments posted to this topic are about the item Logical processors

    Igor Micev,
    My blog: www.igormicev.com

  • This was removed by the editor as SPAM

  • dawryn

    SSCarpal Tunnel

    Points: 4448

    Really? Or are you just kidding? :w00t:

    What was the question about?

    Guessing whether it is physical/virtual machine or capacity limits?

    Or was it about lower edge of maximum capacity limits? :blink:

    Either way explanation is flawed - virtual machine can use 16 virtual processors and it does not matter whether they are hyper-threaded or not (virtual machine is not aware of that).

    In this case logical processors are taken for virtual processors but that is not always true.

  • Koen Verbeeck

    SSC Guru

    Points: 258924

    Interesting question, thanks.

    Need an answer? No, you need a question
    My blog at https://sqlkover.com.
    MCSE Business Intelligence - Microsoft Data Platform MVP

  • Igor Micev

    SSC-Dedicated

    Points: 33109

    dawryn (9/21/2016)


    Really? Or are you just kidding? :w00t:

    What was the question about?

    Guessing whether it is physical/virtual machine or capacity limits?

    You don't have to guess, it clearly states "You have a physical server with 12 physical cores placed in two sockets..."

    Either way explanation is flawed - virtual machine can use 16 virtual processors and it does not matter whether they are hyper-threaded or not (virtual machine is not aware of that).

    For the virtual machines it is different.There, the maximum number of logical processors the Standard edition of 2014 can use is 16.

    At VMs, virtual processors are logical processors, that's all. What is not clear here?

    [/quote]

    In this case logical processors are taken for virtual processors but that is not always true.

    Please tell here when it's not always true. That's the point of the QotT in this site.

    Igor Micev,
    My blog: www.igormicev.com

  • dawryn

    SSCarpal Tunnel

    Points: 4448

    Igor Micev (9/21/2016)


    dawryn (9/21/2016)


    What was the question about?

    Guessing whether it is physical/virtual machine or capacity limits?

    You don't have to guess, it clearly states "You have a physical server with 12 physical cores placed in two sockets..."

    It also clearly states "SQL Server 2014 Standard edition is installed on the server." Here the guess comes in. Or is that something taken? If positive - for whom?

    Either way explanation is flawed - virtual machine can use 16 virtual processors and it does not matter whether they are hyper-threaded or not (virtual machine is not aware of that).

    For the virtual machines it is different.There, the maximum number of logical processors the Standard edition of 2014 can use is 16.

    At VMs, virtual processors are logical processors, that's all. What is not clear here?

    Do you mean: "In a virtualized environment, the compute capacity limit is based on the number of logical processors, not cores, because the processor architecture is not visible to the guest applications." discards usage of virtual processor in communication?

    What about hyper-threading OFF (see below)?

    In this case logical processors are taken for virtual processors but that is not always true.

    Please tell here when it's not always true. That's the point of the QotD in this site.

    It is possible: "One can enable or disable hyperthreading using a BIOS setting for the processor during the BIOS setup..."

  • Carlo Romagnano

    SSC-Insane

    Points: 21743

    Boh, I don't understand:

    The SQL Server 2014 Standard Edition can use up to 16 physical cores. If hyper-threading is enabled on a 16-core server, then there are 32 logical processors, and SQL Server will use all of them.

    Here, it states clearly that SE can use up to 32 LOGICAL PROCESSORS.

    So, I answered "24 logical processors because hyper-threading is enabled". Where's the catch?

  • Igor Micev

    SSC-Dedicated

    Points: 33109

    Carlo Romagnano (9/21/2016)


    Boh, I don't understand:

    The SQL Server 2014 Standard Edition can use up to 16 physical cores. If hyper-threading is enabled on a 16-core server, then there are 32 logical processors, and SQL Server will use all of them.

    Here, it states clearly that SE can use up to 32 LOGICAL PROCESSORS.

    So, I answered "24 logical processors because hyper-threading is enabled". Where's the catch?

    H Carlo,

    I see that I've done a mistake checking the right answer in the question. The correct answer is 24 logical processors.

    How to inform the administrator to correct this?

    Igor Micev,
    My blog: www.igormicev.com

  • Carlo Romagnano

    SSC-Insane

    Points: 21743

    Igor Micev (9/21/2016)


    Carlo Romagnano (9/21/2016)


    Boh, I don't understand:

    The SQL Server 2014 Standard Edition can use up to 16 physical cores. If hyper-threading is enabled on a 16-core server, then there are 32 logical processors, and SQL Server will use all of them.

    Here, it states clearly that SE can use up to 32 LOGICAL PROCESSORS.

    So, I answered "24 logical processors because hyper-threading is enabled". Where's the catch?

    H Carlo,

    I see that I've done a mistake checking the right answer in the question. The correct answer is 24 logical processors.

    How to inform the administrator to correct this?

    Send a message to Steve.

  • shaneoneillis

    SSCommitted

    Points: 1631

    Interesting question. Cheers

  • Igor Micev

    SSC-Dedicated

    Points: 33109

    Carlo Romagnano (9/21/2016)


    Igor Micev (9/21/2016)


    Carlo Romagnano (9/21/2016)


    Boh, I don't understand:

    The SQL Server 2014 Standard Edition can use up to 16 physical cores. If hyper-threading is enabled on a 16-core server, then there are 32 logical processors, and SQL Server will use all of them.

    Here, it states clearly that SE can use up to 32 LOGICAL PROCESSORS.

    So, I answered "24 logical processors because hyper-threading is enabled". Where's the catch?

    H Carlo,

    I see that I've done a mistake checking the right answer in the question. The correct answer is 24 logical processors.

    How to inform the administrator to correct this?

    Send a message to Steve.

    I've written a message to Steve to correct the question's answer. It's my mistake. I'm sorry for that.

    Thanks for the remark!

    Igor Micev,
    My blog: www.igormicev.com

  • Joel Ewald

    SSCertifiable

    Points: 6010

    Still a decent question as I had to look up the difference in the editions.

    I learned something from that and the the comments in the post.

    Thank you for submitting it.

  • paul.knibbs

    SSCoach

    Points: 15270

    Although incorrect, the answer does highlight an interesting difference between a virtual machine and a physical machine where it comes to logical CPU usage which I never knew about, so thanks for that!

  • Steve Jones - SSC Editor

    SSC Guru

    Points: 715334

    Apologies for the wrong checkbox. I thought I had set this correctly, but I may have clicked the wrong answer item.

    Points have been awarded back to this time.

  • George Vobr

    SSCrazy Eights

    Points: 8951

    Thanks Igor for this question. It made me diligently googled and study

    SQL Server Hardware e-book from Glenn Bery and more. Then I found the correct

    answer in an article on Dan Guzman's Blog, which is listed in the references.

    Yeah, you authors of the QotD don't have it easy. 🙂

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