Intel® 64 and IA-32 Architectures Optimization Reference Manual

APPLICATION PERFORMANCE TOOLScritical paths and imbalances in thread execution, etc. Mountains of data arecollapsed into relevant summaries, sorted to identify parallel regions or loops thatrequire attention. Its intuitive, color-coded displays make it easy to assess yourapplication's performance.Figure A-1 shows the execution timeline of a multi-threaded application when run in(a) a single-threaded environment, (b) a multi-threaded environment capable ofexecuting two threads simultaneously, (c) a multi-threaded environment capable ofexecuting four threads simultaneously. In Figure A-1, the color-coded timeline ofthree hardware configurations are super-imposed together to compare processorscaling performance and illustrate the imbalance of thread execution.Load imbalance problem is visually identified in the two-way platform by noting thatthere is a significant portion of the timeline, during which one logical processor hadno task to execute. In the four-way platform, one can easily identify those portions ofthe timeline of three logical processors, each having no task to execute.Figure A-1. Intel Thread Profiler Showing Critical Pathsof Threaded Execution TimelinesA.4.3 Intel Threading Building Blocks 1.0The Intel Threading Building Blocks is a C++ template-based runtime library thatsimplifies threading for scalable, multi-core performance. It can help avoid rewriting,re-testing, re-tuning common parallel data structures and algorithms.A-15