Performance

The SPMD programming model that ispc provides makes it easy to harness the computational power available in SIMD vector units on modern CPUs, while its basis in C makes it easy for programmers to adopt and use productively. This page summarizes the performance of ispc with the workloads in the examples/ directory of the ispc distribution.

These results were measured on a 4-core Apple iMac with a 4-core 3.4GHz Intel® Core-i7 processor using the Intel® AVX instruction set. The basis for comparison is a reference C++ implementation compiled with gcc 4.2.1, the version distributed with OS X 10.7.2. (The reference implementation is also included in the examples/ directory.)

The following table shows speedups for a number of the examples on a 2.40GHz, 40-core Intel® Xeon E7-8870 system with the Intel® SSE4 instruction set, running Microsoft Windows Server 2008 Enterprise. Here, the serial C/C++ baseline code was compiled with MSVC 2010.