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IBM T5140 single core performance

Discussion in 'Sun Hardware' started by thegman, Jun 2, 2008.

  1. thegman

    thegman Guest

    Hi all,
    I've just done some comparative tests between a Sun Blade 2000
    (2x1GHz) and our new T5140 (2x6x1.2GHz), and the single core
    performance on the T5140 is somewhat less than I expected. Before I
    start dtracing, and all other kinds of tests, I'd like to know if I
    should be expecting more from the T5140. Basically, we run Adobe
    Distiller Server on both, to distill a large EPS file into a PDF on
    the Blade took 8.8 seconds, on the T5140 it took just over 16 seconds.
    This would rate clock-for-clock, a core on the T5140 a bit less than
    half the USIII in the Blade.

    I'll be honest, I expected the single core performance to be not
    great, but this is much worse than I thought, particularly as I was
    told at a Sun customer briefing to expect clock-for-clock to be much
    the same as USIII.

    Is this worth investigating further, or does this sound about right?

    Cheers

    GT
     
    thegman, Jun 2, 2008
    #1
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  2. thegman

    Marc Guest

    It sounds about right to me. The CPU in T2 processors is much simpler
    than an USIII. You could run at least 24 distiller jobs simultaneously
    and it would still all be done in 16 seconds, and the slowdown should be
    low up to 96 jobs.
     
    Marc, Jun 2, 2008
    #2
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  3. thegman

    thegman Guest

    I see, certainly we can run many jobs at a time, and get good results
    out of the machine, but some are stuck on single cores, and I was told
    by a Sun representative that T2+ cores were much better than the T1
    predecessor for single core loads, but I'm not noticing any
    difference, if anything, it's worse.

    I guess if that's the best we can expect, then will need to try to
    parallelize the jobs more.
     
    thegman, Jun 2, 2008
    #3
  4. thegman

    Dave Guest


    Does this chip have a decent floating point unit? I gather some of these
    chips intended for non-floating point code do poorly if you try to get
    them to do it.

    Just a thought - I don't know much about this.
     
    Dave, Jun 2, 2008
    #4
  5. thegman

    Marc Guest

    Say single-thread instead of single-core ;-)

    Just for a quick estimate, you can imagine a T2+ core as 2 T1 cores that
    got merged, except that they now have a real FPU and an improved crypto
    unit. And the clock speed may have been slightly increased. So unless you
    are doing crypto or floating points, it isn't that different for a single
    thread.

    PS: check anything I say with other sources, as I am not an expert.
     
    Marc, Jun 2, 2008
    #5
  6. thegman

    thegman Guest

    You're right, I should get into the habit of saying "single thread". I
    think what we'll probably do is alter our workloads a bit to scale
    better, the loads we run which *do* scale get great results on the
    T5140, it's just a shame the single-thread numbers are that bad, if
    they were more like US-III cores, then the T2+ would be an incredible
    processor, right now, I'd say it was just "very good".
     
    thegman, Jun 2, 2008
    #6
  7. thegman

    Drazen Kacar Guest

    There are various tools which can provide some numbers, like lockstat
    and trapstat. They should be a bit easier to use than writing dtrace
    scripts.
    It all depends on where the jobs get stuck. If there are no hardware
    resources, you can't do a thing (assuming you can't rewrite the
    application). If it's some kind of software housekeeping, black magick
    is usually possible. :)
     
    Drazen Kacar, Jul 29, 2008
    #7
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