User Guide

Contents

Setting Node Weight

The weight determines the simulated amount of time the node spins or does active work per data item passed to the node. The default unit for the weight is microseconds. For example, per the default unit of microseconds, a weight value of 1000 makes a node spin for half a second.
  • If the specified weight is high relatively to the unit, the computation might run for a longer time.
  • If the graph has an associated trace, the unit of the weight is overwritten by the unit specified in the trace.
To edit a node weight:
  1. Select a node in the canvas.
  2. Click the
    Node Weight
    field value in the
    Node
    tab of the
    Properties
    pane and enter your value.
    node weight field
The weight value matters only for nodes with a body, such as
source_node
,
continue_node
,
function_node
,
multifunction_node
,
async_node
, and
tag_matching join_node
. Other nodes that simply assist in the topology of the graph do not use the weight value. For example, specifying a weight value for a
broadcast_node
has no effect on the node.
Consider the following:
  • To prevent long runtimes, the scalability analysis scales all runs with total serial times beyond a certain threshold. The current default threshold is 5 seconds. To modify this value:
    1. Go to the
      Edit
      Preferences
      .
    2. Open the
      TBB
      category,
      Scalability
      tab.
    3. Modify a value in the
      Serial Run Time(s)
      field.
    The total serial runtime also considers the number of data items passed through the graph. For example, a graph with a serial runtime of 10 seconds and 4 data items has a total serial runtime of 40 seconds.
  • To ensure node weights are not scaled into regions that make the overhead dominant, the analysis uses original weights and does not implement scaling if no node has a weight of 100 microseconds after scaling.
  • If a graph contains nodes with performance that could benefit from the use of the TBB lightweight policy, the analysis activates the lightweight policy for the recommended nodes and lists the possible improvement in the results.

Product and Performance Information

1

Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804