Intel® Advisor User Guide

User Guide

Contents

Setting Concurrency Specification

The concurrency specification is a list of the number of threads on which the graph is run. To set the concurrency:
  1. Open the
    Preferences
     window.
  2. Go to the
    Scalability
    TBB
     category.
  3. Set the list in the
    Concurrency Specification
     field in the
    1,
    a
    -
    b
    :
    n
     format, where:
    • 1
       is the serial run. Because the speedup is estimated with respect to a serial run of a graph, by default, all graphs are first run serially before running on multiple threads. The addition of 1 is merely symbolic and informational, as its omission has no effect on the list.
    • a
       is the starting number of multiple threads.
    • b
       is the ending number of multiple threads.
    • n
       is the step size.
    preferences dialog box
The default end value is the number of cores on the system and the default step size is a quarter of this value. The end value is always included in the list, even if it is not a direct multiple of the step size.
As an example, on a 32-core system, the default is
1,8-32:8
. This results in the list
1,8,16,24,32
, as shown below.
analytics report for 32 core system
Other supported formats are
a,b,c
 or only
a
 if you want to see the speedup for only one set of threads.
You can also combine formats. The following shows some valid concurrency specifications:
  • Range without a step size:
    16-64
     yields
    1,16,32,48,64
  • Range with a step size:
    16-64:8
     yields
    1,16,24,32,40,48,56,64
  • Single value:
    16
     yields
    1,16
  • List of values:
    16,32,64
     yields
    1,16,32,64
  • Mix of range and list:
    16-64,40,48,56
     yields
    1,16,32,40,48,56,64

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.