Thread: True or false

  1. #1
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    True or false

    Having multiple processors is completly transparent when programming with C++. As in, the OS takes care of scheduling on the different processors. Correct?


    I read something about it in a book of mine... but I can't find it right now.

  2. #2
    5|-|1+|-|34|) ober's Avatar
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    True... it should have nothing to do with how you code something.
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  3. #3
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    How about with assembler? Is there any special preparation/code for multiple processors?

  4. #4
    &TH of undefined behavior Fordy's Avatar
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    Originally posted by Eibro
    How about with assembler? Is there any special preparation/code for multiple processors?
    On an app level, the OS will control the implementation so you shouldnt see any difference...

    If you are writting an os or going low level, then you will have to account for it obviously....

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    So, could one process be running different threads on different CPU's at the same time?

  6. #6
    It's full of stars adrianxw's Avatar
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    >>> Having multiple processors is completly transparent when programming with C++.

    In general, yes, but...

    >>> So, could one process be running different threads on different CPU's at the same time?

    ... once you start doing things like this, you can run into race conditions, word tearing, cache misses and all manner of things. However, you can get enormous performance lifts. Our DEC Alpha's have multiple processors and the VMS operating system supports POSIX compliant multithreading, fun.
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  7. #7
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    Alright, i'm just arguing with someone about this.
    A few more:
    True or false;

    On a system which supports (and implements) multiple CPUs, it is feasable that a single process will get time on both CPUs for its different threads.

    A process will reap a performance increase with 2 CPU's of the same MHZ, then it will with 1 of the same MHZ (wow, this is a stupid one)

  8. #8
    Disagreeably Disagreeable
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    >On a system which supports (and implements) multiple CPUs, it is feasable that a single process will get time on both CPUs for its different threads.<

    That's really dependent on the way the OS at hand implements SMP.

  9. #9
    Redundantly Redundant RoD's Avatar
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    On a system which supports (and implements) multiple CPUs, it is feasable that a single process will get time on both CPUs for its different threads.

    A process will reap a performance increase with 2 CPU's of the same MHZ, then it will with 1 of the same MHZ (wow, this is a stupid one)
    This is all dependent on the o/s. With something like Windows the first one may be true, but the second one probably won't be. I would have to say your more likely to get a good dual cpu usage more from say linux then windows.

  10. #10
    &TH of undefined behavior Fordy's Avatar
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    Originally posted by Ride -or- Die
    I would have to say your more likely to get a good dual cpu usage more from say linux then windows.
    That would depend on the type of Windows......if its toy windows (95-ME) then true....if its decent windows like 2000 etc .....then it gives MultiProcessor support

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