Skylake AVX-512 Benchmarks With GCC 8.0

Written by Michael Larabel in GNU on 28 November 2017 at 02:24 PM EST. 27 Comments
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For those curious about the current benefits of AVX-512, here are some benchmarks using a recent snapshot of the GCC 8 compiler and comparing the performance of the generated binaries for the skylake and skylake-avx512 targets.

AVX-512 right now is limited to just the Intel server and X-Series processors, but as we've reported already, Intel has effectively confirmed AVX-512 support for the Cannonlake desktop CPU line-up through GCC/Clang patches noting the AVX-512 addition. So due to greater AVX-512 availability on the horizon and continued AVX-512 improvements in GCC8, I ran some fresh benchmarks using the high-end Core i9 7980XE test system running Ubuntu Linux.

GCC 8.0.0 was built from Git on 25 November and with the i9-7980XE, the benchmarks were run after built with the "-O3 -march=skylake" and then the "-O3 -march=skylake-avx512" compiler flags. Over the conventional Skylake target, the -march=skylake-avx512 adds AVX512F, AVX512VL, AVX512BW, AVX512DQ, and AVX512CD.

Further and a wider range of GCC 8 (and Clang 6) compiler benchmarks on more hardware will be coming soon while this can be treated as just a quick AVX-512 testing roundabout.

There are some minor improvements to note when targeting skylake-avx512, but there were also a couple of slowdowns:

All these test details and more data is available from this result file.
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Michael Larabel is the principal author of and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 20,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and automated benchmarking software. He can be followed via Twitter, LinkedIn, or contacted via

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