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  1. #1
    Join Date
    May 2006
    Posts
    1,398

    core multiplexing

    Has anyone compared the performance with core-multiplexng enabled vs. disabled on webservers?

    I read up on it but are seeing mixed opinions. Some say its better for single threaded apps, that it actually makes them use the multicores. Others say it is better for both multithreaded and single threaded apps.

    I have done a benchmark test of one server with core-multiplexing and one without. http://www.webhostingtalk.com/showpo...postcount=1287

    The one without scored much higher on the benchmark but then again the benchmark may not actually give accurate results when it comes to that. Has anyone here monitored servers running with and without to see a difference?

    And does anyone know much about this new tech in general?

  2. #2
    Join Date
    Apr 2003
    Location
    San Jose, CA.
    Posts
    1,622
    Doesn't seem surprising.

    From what I read, "Core multiplexing" is a badly described term for a strange concept.

    At this point I see two completely different descriptions of what Core Multiplexing might be doing:
    1)What you're doing is disabling one core, so that the other core gets twice the cache.
    2)Reverse Hyper-Threading... where a single threaded app is predictively threaded to use multiple cores.

    If what's happening is #1, then the behavior you're seeing is completely expected.
    If what's happening is #2, then the technology sucks at this point. But, to be fair, you're running a single threaded app 4 times concurrently, so if you're trying to spread those 4 single threaded apps across 4 cores with core multiplexing on, you're just adding a lot of useless context switching.

    In general, in a webhosting environment, whichever method is being utilized... neither makes sense and you'd do better to leave it off.
    Last edited by Lightwave; 01-09-2008 at 03:13 AM.
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