FAQ — Unlimited Threading

  1. Why is Pixar announcing unlimited threading?
    Current and future multi-core processors continue to increase in size and potential performance, and Pixar has invested heavily in threading RenderMan® to take advantage of this expanding capacity. We also believe that a new license model is necessary to reflect the realties of current technology trends, a model that is both flexible and adaptable and not limited by the specifics of any particular hardware platform. Unlimited threading addresses all of these requirements and is easy to understand and administer.
  2. What are the key differences between the existing licensing and an unlimited threads license?
    An existing RenderMan license (RPS v14.0, RMS v2.0, RfM v3.0) can use up to 4 threads per license, with thread-sharing possible between license invocations in some cases.  On a four-core processor you might allocate these four threads in several ways: rendering one frame using 4 threads, 2 frames simultaneously using 2 threads each, or 4 frames at the same time using 1 thread. (Memory permitting)
    The simpler new unlimited threading model (RPS v15.0, RMS v3.0, RfM v4.0) will allow each license to use any number of threads. For example, if you have a dual quad machine, then RenderMan can automatically allocate a full rendering thread to each of the 8 processors to render your frame.  This model scales simply to upcoming hardware and the entire compute capacity of machines with 16 cores or more can if desired be assigned to a singe rendering session. It should be noted that unlimited threading applies to each license invocation, reflecting the simplified model and current industry trends in application development and usage patterns.
  3. Will I lose anything if I can run only one invocation per RenderMan license?
    We do not believe so. Unlimited threading allows you to fully leverage RenderMan engineering advances in thread and memory efficiency from recent and upcoming product releases. It allows you to plan for increasingly large multi-core machines in future without being concerned if your RenderMan license can take advantage of that additional compute capacity. We believe the unlimited threading model is a reasonable balance and a positive advantage to your productivity.
  4. Will rendering with a thread-per-core always be best practice and does this mean I only ever need one license per machine?
    Threading scalability is both non-linear and very scene-specific.  Actual benchmarking with your own data is the only way to determine the best allocation of resources for your needs, however, as a broad rule of thumb, RenderMan today achieves a good balance of performance and efficiency using 4 to 8 threads per frame on a broad variety of scenes.  Overall throughput for certain types of work can sometimes benefit from running several independent frames concurrently on the same host, each using a smaller number of threads.  Choosing an optimal number of threads is a moving target, dependent on changing hardware and the continual improvements in the core RenderMan algorithms. Unlimited threading provides the flexibility to take advantage of these continuing improvements without being restrained by licensing limitations.
  5. Can I run a single RenderMan license with unlimited threads over multiple machines?
    No. Each RenderMan license is invoked to run on any one specific machine. (Irrespective of whether that license is floating or node-locked) You cannot split an invocation of any one RenderMan license over multiple machines.
  6. Is there any difference between the way floating and node-locked licenses run?
    No, both licenses use unlimited threads in exactly the same manner.
  7. When is the new RenderMan Pro Server v15.0 with unlimited threading available?
    RenderMan Pro Server v15.0 is currently in late beta and we anticipate shipping in the fall of 2009.
  8. Can I buy RenderMan Pro Server v14.0 and automatically obtain the new RenderMan Pro Server 15.0 with unlimited threads when it is released in the fall?
    Yes. All sales of RenderMan Pro Server v14.0 from SIGGRAPH onwards are entitled to a free upgrade to RenderMan Pro Server v15.0 when it is released.
  9. When will the next version of RenderMan Studio with unlimited threads be released?
    We currently anticipate that RenderMan Studio v3.0 will enter beta in the fall. RenderMan Studio customers on current maintenance will be eligible for beta access. No release date has been announced yet.
  10. If I cannot wait until RMS v3.0 for unlimited threads can you loan me additional licenses?
    No, we are not able to “bring forwards” unlimited threading or equivalent capacity through additional licenses until the upgrade software is formally released. All RenderMan Studio customers on current maintenance will receive unlimited threading at that point. A separate upgrade option will be available for customers who are not on maintenance.
  11. When will the next version of RenderMan for Maya with unlimited threads be released?
    We currently anticipate that RenderMan for Maya v4.0 will enter beta in the fall of 2009 in parallel with RenderMan Studio v3.0. A beta program for existing RenderMan for Maya users will be made available. Please check the RenderMan for Maya forum for updates. No release date has been announced yet.
  12. How will unlimited threads work with the forthcoming Tractor™ v1.0?
    Tractor works by managing an arbitrary number of active tasks such as an invocation of a RenderMan license. Tractor is not concerned with how many threads or cores each task actually uses.


If this FAQ does not completely answer your questions, please contact us directly at rendermansales@pixar.com.

TM & © 1986 - Pixar. All Rights Reserved.