Rendering and HPC Benchmark Session Using Our Best Servers

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• jaguarpp - Friday, September 30, 2011 - link

  what if instead of using a full program, create a small test program that is compiled for each platform something like
  declare variables int, floats, arrays to test diferent workloads
  put the variables on loops and do some operation sum, div, the integers then the floats and so on measure the time that take to exit from each block
  the hardest part will be how to make it threadable
  and get acces to diferent compilers, maybe a friend?
  anyway great article i really enjoy it even when i never get close to that class of hardware
  thanks very much for the reading

• Michael REMY - Friday, September 30, 2011 - link

  very interesting analyze but...why use a score in cinebench instead a time render score ?
  
  Time result are more meaning for common and pro user than integer score !

• MrSpadge - Friday, September 30, 2011 - link

  Because time is totally dependent on the complexity of your scene, output resolution etc. And the score can be directly translated into time if you know the time for any of the configurations tested.
  
  MrS

• Casper42 - Friday, September 30, 2011 - link

  Go back to Quanta and see if they have a newer BIOS with the Core Disable feature properly implemented. I Know the big boys are now implementing the feature and it allows you to disable as many cores as you want as long as its done in pairs. So your 10c proc can be turned into 2/4/6/8 core versions as well.
  
  So for your first test where you had to turn HT off because 80 threads was too much, you could instead turn off 2 cores per proc and synthetically create a 4p32c server and then leave HT on for the full 64 threads.

• alpha754293 - Sunday, October 2, 2011 - link

  "Hyper-Threading offers better resource utilization but that does not negate the negative performance effect of the overhead of running 80 threads. Once we pass 40 threads on the E7-4870, performance starts to level off and even drop."
  
  It isn't thread-locking that limits the performance. It isn't because it has to sync/coordinate 80-threads. It's because there's only 40 FPUs available to do the actual calculations on/with.
  
  Unlike virtualization, where thread locking is a real possiblity because there really isn't much in the way of underlying computations (I would guess that if you profiled the FPU workload, it wouldn't show up much), whereas for CFD, solving the Navier-Stokes equations requires a HUGE computational effort.
  
  it also depends on the means that the parallelization is done, whether it's multi-threading, OpenMP, or MPI. And even then, within different flavors of MPI, they can also yield different results; and to make things even MORE complicated, how the domain is decomposed also can make a HUGE impact on performance as well. (See the studies performed by LSTC with LS-DYNA).

• alpha754293 - Sunday, October 2, 2011 - link

  Try running Fluent (another CFD) code and LS-DYNA.
  
  CAUTION: both are typically usually VERY time-intensive benchmarks, so you have to be very patient with them.
  
  If you need help in setting up standardized test cases, let me know.

• alpha754293 - Sunday, October 2, 2011 - link

  I'm working on trying to convert an older CFX model to Fluent for a full tractor-trailer aerodynamics run. The last time that I ran that, it had about 13.5 million elements.

• deva - Monday, October 3, 2011 - link

  If you want something that currently scales well, Terra Vista would be a good bet (although it is expensive).
  
  Have a look at the Multi Machine Build version.
  
  http://www.presagis.com/products_services/products...
  
  "...capability to generate databases of
  100+ GeoCells distributed to 256 individual
  compute processes with a single execution."
  
  That's the bit that caught my eye and made me think it might be useful to use as a benchmarking tool.
  
  Daniel.

• mapesdhs - Tuesday, October 4, 2011 - link

  
  Have you guys considered trying C-ray? It scales very well with no. of cores, benefits from as
  many threads as one can throw at it, and the more complex version of the example render
  scene stresses RAM a bit aswell (the small model doesn't stress RAM at all, deliberately so).
  I started a page for C-ray (Google for, "c-ray benchmark", 1st link) but discovered recently
  it's been taken up by the HPC community and is now part of the Phoronix Test Suite (Google
  for, "c-ray benchmark pts", 1st link again). I didn't create C-ray btw (creds to John Tsiombikas),
  just took over John's results page.
  
  Hmm, don't suppose you guys have the clout to borrow or otherwise have access to an SGI
  Altix UV? Would be fascinating to see how your tests scale with dozens of sockets instead of
  just four, eg. the 960-core UV 100. Even a result from a 40-core UV 10 would be interesting.
  Shared-memory system so latency isn't an issue.
  
  Ian.

• shodanshok - Wednesday, October 5, 2011 - link

  Hi Johan,
  thank you for the very interesting article.
  
  The Hyperthreading ON vs OFF results somewhat surprise me, as Windows Server 2008 should be able to prioritize hardware core vs logical ones. Was this the case, or you saw that logical processors were used before full hardware core utilization? If so, you probably encounter one corner case were extensive hardware sharing (and contention) between two threads produce lower aggregate performance.
  
  Regards.