Compiler Tuning With Intel Ivy Bridge Processors

In this article is a look at the impact that compiler tuning has for the latest-generation Intel Ivy Bridge processors. Being tested is the GNU Compiler Collection (GCC) while passing various architecture flags to look at the impact they have on the results.

The Intel Core i7 3770K "Ivy Bridge" system was once again used since it is the only Ivy Bridge processor available right now at Phoronix. This compiler tuning complements the earlier 11-Way Intel Ivy Bridge Compiler Comparison results.

First up are the results for GCC 4.7.0 when building all of the benchmarks each time with the CFLAGS/CXXFLAGS set to -O3 and then switching between -march=nocona, -march=core2, -march=corei7, -march=corei7-avx, and -march-core-avx-i. Below is a description of these architecture differences as it concerns GCC from their provided documentation.

Nocona: Improved version of Intel Pentium 4 CPU with 64-bit extensions, MMX, SSE, SSE2 and SSE3 instruction set support.

Core2: Intel Core 2 CPU with 64-bit extensions, MMX, SSE, SSE2, SSE3 and SSSE3 instruction set support.

Corei7: Intel Core i7 CPU with 64-bit extensions, MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1 and SSE4.2 instruction set support.

Corei7-avx: Intel Core i7 CPU with 64-bit extensions, MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AVX, AES and PCLMUL instruction set support.

Core-avx-i: Intel Core CPU with 64-bit extensions, MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AVX, AES, PCLMUL, FSGSBASE, RDRND and F16C instruction set support.