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HardwareSupport.md

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Introduction

This wiki is intended to track the support for various hardware types within the BLIS framework source distribution.

We apologize if this wiki falls out of date. For the latest support, we recommend peeking inside of the relevant sub-configuration (specifically, in the bli_cntx_init_<configname>.c file) and looking at which kernels are registered. You may also contact the blis-devel mailing list.

Level-3 microkernels

The following table lists architectures for which there exist optimized level-3 microkernels, which microkernels are optimized, the name of the author or maintainer, and the current status of the microkernels.

A few remarks / reminders:

  • Optimizing only the gemm microkernel will result in optimal performance for all level-3 operations except trsm (which will typically achieve 60 - 80% of attainable peak performance).
  • The trsm operation needs the gemmtrsm microkernel(s), in addition to the aforementioned gemm microkernel, in order reach optimal performance.
  • Induced complex (1m) implementations are employed in all situations where the real domain gemm microkernel of the corresponding precision is available, but the "native" complex domain gemm microkernel is unavailable. Note that the table below lists native kernels, so if a microarchitecture lists only sd, support for both c and z datatypes will be provided via the 1m method. (Note: most people cannot tell the difference between native and 1m-based performance.) Please see our ACM TOMS article on the 1m method for more info on this topic.
  • Some microarchitectures use the same sub-configuration. This is not a typo. For example, Haswell and Broadwell systems as well as "desktop" (non-server) versions of Skylake, Kaby Lake, and Coffee Lake all use the haswell sub-configuration and the kernels registered therein. Microkernels can be recycled in this manner because the key detail that determines level-3 performance outcomes is actually the vector ISA, not the microarchitecture. In the previous example, all of the microarchitectures listed support AVX2 (but not AVX-512), and therefore they can reuse the same microkernels.
  • Remember that you (usually) don't have to choose your sub-configuration manually! Instead, you can always request configure-time hardware detection via ./configure auto. This will defer to internal logic (based on CPUID for x86_64 systems) that will attempt to choose the appropriate sub-configuration automatically.
  • There is a difficulty in automatically choosing the ideal sub-configuration for use on Skylake-X systems, which may have one or two FMA units. The skx sub-configuration is only beneficial when used on hardware with two FMA units. Otherwise the hardware is treated as a "desktop" Skylake system, which uses the haswell sub-configuration. Furthermore, the number of units can't be queried directly; instead, we rely on a manually-maintained list of CPU models (via logic in frame/base/bli_cpuid.c), which may be incorrect for new processors, particularly Gold models. In that case, you can either fix the code (and please raise an issue!) or manually target the skx at configure-time (i.e., ./configure [options] skx). If your performance seems low, you can set export BLIS_ARCH_DEBUG=1, which will cause BLIS to output some basic debugging info to stderr that will reveal whether your system was detected as having one or two VPUs (FMA units).
Vendor/Microarchitecture BLIS sub-configuration gemm gemmtrsm
AMD Bulldozer (AVX/FMA4) bulldozer sdcz
AMD Piledriver (AVX/FMA3) piledriver sdcz
AMD Steamroller (AVX/FMA3) steamroller sdcz
AMD Excavator (AVX/FMA3) excavator sdcz
AMD Zen (AVX/FMA3) zen sdcz sd
Intel Core2 (SSE3) penryn sd d
Intel Sandy/Ivy Bridge (AVX/FMA3) sandybridge sdcz
Intel Haswell, Broadwell (AVX/FMA3) haswell sdcz sd
Intel Sky/Kaby/CoffeeLake (AVX/FMA3) haswell sdcz sd
Intel Knights Landing (AVX-512/FMA3) knl sd
Intel SkylakeX (AVX-512/2×FMA3) skx sd
Intel SkylakeX (AVX-512/1×FMA3) haswell sdcz sd
ARMv7 Cortex-A9 (NEON) cortex-a9 sd
ARMv7 Cortex-A15 (NEON) cortex-a15 sd
ARMv8 Cortex-A53 (NEON) cortex-a53 sd
ARMv8 Cortex-A57 (NEON) cortex-a57 sd
ARMv8.1 ThunderX2 (NEON) thunderx2 sd
ARMv8.1 A64FX (SVE) a64fx d
IBM Blue Gene/Q (QPX int) bgq d
IBM Power7 (QPX int) power7 d
template (C99) template sdcz sdcz

Level-1f kernels

Not yet written. Please see the relevant sub-configuration (bli_cntx_init_<configname>.c) to determine which kernels are implemented/registered.

Level-1v kernels

Not yet written. Please see the relevant sub-configuration (bli_cntx_init_<configname>.c) to determine which kernels are implemented/registered.