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Sun T2000 without the threads

Discussion in 'Sun Hardware' started by tony, Apr 27, 2006.

  1. tony

    tony Guest

    I want to replace an E6500 (24 x UltraSparc-II @ 400MHz) with an 8-core
    T2000. From what I have read, the T2000 would beat the E65k easily as a
    web server. The problem is, I don't think our application can take
    advantage of the 4-way multithreading in the Niagara cores. It is a web
    site with the majority of the CPU going into CGI processing. There are
    multiple processes but I doubt they are multithreaded. Rewriting the
    app is not an option.

    So, the equation isn't 24 threads vs. 32 threads. It's 24 simultaneous
    processes (US-II, 400MHz) vs. 8 simultaneous processes ( T1, 1.0 Ghz).
    Which server wins?
     
    tony, Apr 27, 2006
    #1
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  2. tony

    Rich Teer Guest

    That shouldn't present a problem. Each single threaded process is
    "just" another thread, so the T1 should thrive on them almost as well
    as one multithreaded process.
    If I were a betting man, I'd go for the T2000.

    --
    Rich Teer, SCNA, SCSA, OpenSolaris CAB member

    President,
    Rite Online Inc.

    Voice: +1 (250) 979-1638
    URL: http://www.rite-group.com/rich
     
    Rich Teer, Apr 27, 2006
    #2
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  3. tony

    tony Guest

    Ahh, I was thinking about threading at the wrong level. The OS itself
    is a multithreaded application, even if there is no threading within
    the user processes. At least, that's what I think you meant. Thanks for
    setting me straight.
     
    tony, Apr 27, 2006
    #3
  4. tony

    Frank Cusack Guest

    My guess would be that the E6500 wins.

    http://www.sun.com/blueprints/1205/819-5144.pdf says that multiprocess
    apps will scale well, but maybe they just say that because the T1 is
    multicore as well as CMT. Each core shares 1 TLB across its 4
    strands, so ISTM that you can't run more than 1 processes on a core
    without incurring severe penalties from TLB invalidation when changing
    strands.

    You should apply for try-and-buy.

    -frank
     
    Frank Cusack, Apr 27, 2006
    #4
  5. Multiple processes, multiple threads; that really doesn't matter that
    much; the Niagara provides 32 virtual CPUs and it can run 32 CPUs
    at the same time.

    Casper
     
    Casper H.S. Dik, Apr 28, 2006
    #5
  6. tony

    Frank Cusack Guest

    what about TLB limits?
     
    Frank Cusack, Apr 29, 2006
    #6
  7. Interesting blueprint on the T1, including an entire section on tuning the TLB

    http://www.sun.com/blueprints/1205/819-5144.pdf


    Reducing TLB Misses

    The operating system automatically attempts to reduce TLB misses using
    the Multiple Page Size Support (MPSS) feature. In the Solaris 10 12/05
    operating system, text, heap, anon and stack are all automatically placed
    on large pages. The operating system applies a set of heuristics for large
    page allocation. Use the pmap command to ensure a process was allocated
    correctly. Additional information on the MPSS features of the Solaris 10 OS
    can be found in the mpss.so.1(1) man page. For many years, the Solaris OS
    has had a performance optimization called Intimate Shared Memory (ISM),
    which allocates on large pages where possible and locks down memory.
    The default page size for ISM on UltraSPARC T1 processor-based systems
    is 256-megabyte pages.
     
    Oscar del Rio, May 1, 2006
    #7
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