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Archspec

Archspec is a Julia package to get access to the information provided by archspec-json, part of the Archspec project.

CPU Microarchitectures

A CPU microarchitecture is modeled in Archspec.jl by the Microarchitecture structure. Instances of this structure are constructed automatically from archspec-json to populate a dictionary of known microarchitectures:

julia> using Archspec
julia> Archspec.CPUTargetsDict{String, Archspec.Microarchitecture} with 52 entries:
  "icelake"     => Microarchitecture("icelake", Set(["sse4_1", "bmi1", "adx", "…
  "cannonlake"  => Microarchitecture("cannonlake", Set(["adx", "clflushopt", "s…
  "x86_64_v2"   => Microarchitecture("x86_64_v2", Set(["mmx", "sse2", "ssse3", …
  "sparc64"     => Microarchitecture("sparc64", Set{String}(), Dict{String, Arc…
  "core2"       => Microarchitecture("core2", Set(["mmx", "sse2", "ssse3", "sse…
  "broadwell"   => Microarchitecture("broadwell", Set(["movbe", "mmx", "sse2", …
  "prescott"    => Microarchitecture("prescott", Set(["mmx", "sse2", "sse3", "s…
  "graviton"    => Microarchitecture("graviton", Set(["fp", "evtstrm", "sha2", …
  "thunderx2"   => Microarchitecture("thunderx2", Set(["atomics", "evtstrm", "s…
  "power9le"    => Microarchitecture("power9le", Set{String}(), Dict{String, Ar…
  "piledriver"  => Microarchitecture("piledriver", Set(["abm", "mmx", "sse2", "…
  "x86_64_v3"   => Microarchitecture("x86_64_v3", Set(["movbe", "abm", "mmx", "…
  "steamroller" => Microarchitecture("steamroller", Set(["abm", "mmx", "sse2", …
  "riscv64"     => Microarchitecture("riscv64", Set{String}(), Dict{String, Arc…
  "graviton2"   => Microarchitecture("graviton2", Set(["atomics", "fp", "lrcpc"…
  "westmere"    => Microarchitecture("westmere", Set(["mmx", "sse2", "ssse3", "…
  "zen2"        => Microarchitecture("zen2", Set(["xsaveopt", "abm", "sse2", "b…
  "power8le"    => Microarchitecture("power8le", Set{String}(), Dict{String, Ar…
  "nehalem"     => Microarchitecture("nehalem", Set(["mmx", "sse2", "ssse3", "s…
  ⋮             => ⋮

Archspec.CPUTargets maps the names of the microarchitectures to a corresponding Microarchitecture object:

julia> using Archspec

julia> Archspec.CPUTargets["broadwell"]
Archspec.Microarchitecture("broadwell", Set(["movbe", "mmx", "sse2", "ssse3", "pclmulqdq", "rdrand", "bmi2", "rdseed", "aes", "avx", "sse4_2", "popcnt", "fma", "avx2", "sse", "sse4_1", "f16c", "bmi1", "adx"]), Dict{String, Archspec.Compiler}("apple-clang" => Archspec.Compiler("broadwell", "apple-clang", Archspec.CompilerSpec[Archspec.CompilerSpec("broadwell", "-march=broadwell -mtune=broadwell", VersionSpec("8.0.0-*"), "")]), "aocc" => Archspec.Compiler("broadwell", "aocc", Archspec.CompilerSpec[Archspec.CompilerSpec("broadwell", "-march=broadwell -mtune=broadwell", VersionSpec("2.2.0-*"), "")]), "intel" => Archspec.Compiler("broadwell", "intel", Archspec.CompilerSpec[Archspec.CompilerSpec("broadwell", "-march=broadwell -mtune=broadwell", VersionSpec("18.0.0-*"), "")]), "gcc" => Archspec.Compiler("broadwell", "gcc", Archspec.CompilerSpec[Archspec.CompilerSpec("broadwell", "-march=broadwell -mtune=broadwell", VersionSpec("4.9.0-*"), "")]), "clang" => Archspec.Compiler("broadwell", "clang", Archspec.CompilerSpec[Archspec.CompilerSpec("broadwell", "-march=broadwell -mtune=broadwell", VersionSpec("3.9.0-*"), "")])), ["haswell"], "GenuineIntel")

Basic queries

A Microarchitecture object can be queried for its name and vendor:

julia> uarch = Archspec.CPUTargets["broadwell"];

julia> uarch.name
"broadwell"

julia> uarch.vendor
"GenuineIntel"

A microarchitecture can also be queried for features:

julia> "avx" ∈ Archspec.CPUTargets["broadwell"]
true

julia> "avx" ∈ Archspec.CPUTargets["thunderx2"]
false

julia> "neon" ∈ Archspec.CPUTargets["thunderx2"]
true

The verbatim list of features for each object is stored in the features field:

julia> Archspec.CPUTargets["nehalem"].features
Set{String} with 7 elements:
  "mmx"
  "sse2"
  "ssse3"
  "sse4_2"
  "popcnt"
  "sse"
  "sse4_1"

julia> Archspec.CPUTargets["thunderx2"].features
Set{String} with 11 elements:
  "atomics"
  "evtstrm"
  "sha2"
  "asimdrdm"
  "aes"
  "cpuid"
  "asimd"
  "crc32"
  "sha1"
  "pmull"
  "fp"

julia> Archspec.CPUTargets["power9le"].features
Set{String}()

Finally, you can also make set comparison operations between microarchitectures:

julia> Archspec.CPUTargets["nehalem"] < Archspec.CPUTargets["broadwell"]
true

julia> Archspec.CPUTargets["nehalem"] == Archspec.CPUTargets["broadwell"]
false

julia> Archspec.CPUTargets["nehalem"] >= Archspec.CPUTargets["broadwell"]
false

julia> Archspec.CPUTargets["nehalem"] > Archspec.CPUTargets["a64fx"]
false

Compiler's optimization flags

Another information that each microarchitecture object has available is which compiler flags needs to be used to emit code optimized for itself:

julia> optimization_flags(Archspec.CPUTargets["broadwell"], "clang", v"11.0.1")
"-march=broadwell -mtune=broadwell"

Sometimes compiler flags change across versions of the same compiler:

julia> optimization_flags(Archspec.CPUTargets["thunderx2"], "gcc", v"5.1")
"-march=armv8-a+crc+crypto"

julia> optimization_flags(Archspec.CPUTargets["thunderx2"], "gcc", v"9.1")
"-mcpu=thunderx2t99"

If a compiler is known to not be able to optimize for a given architecture an exception is raised:

julia> optimization_flags(Archspec.CPUTargets["icelake"], "gcc", v"4.8.5")
ERROR: cannot produce optimized binary for micro-architecture "icelake" with gcc@4.8.5
Stacktrace:
 [1] error(s::String)
   @ Base ./error.jl:33
[...]

API Reference

Archspec.Compiler — Type
Compiler

Compiler is a composite structure modeling a compiler for a given microarchitecture.

source
Archspec.CompilerSpec — Type
CompilerSpec

CompilerSpec is a composite structure modeling an instance of a compiler for a given microarchitecture and a specific version number, or range of versions.

source
Archspec.optimization_flags — Method
optimization_flags(microarchitecture::Microarchitecture, compiler::String, version::VersionNumber)

Return the list of compiler flags for the given micro-architecture using the given compiler version.

julia> optimization_flags(Archspec.CPUTargets["x86_64_v2"], "gcc", v"5.2")
"-march=x86_64_v2 -mtune=generic -mcx16 -msahf -mpopcnt -msse3 -msse4.1 -msse4.2 -mssse3"

julia> optimization_flags(Archspec.CPUTargets["x86_64_v2"], "gcc", v"11.1")
"-march=x86_64_v2 -mtune=generic"
source
Base.in — Method
in(feature::String, m::Microarchitecture) -> Bool
∈(feature::String, m::Microarchitecture) -> Bool

Return whether the given feature is available in the microarchitecture m.

julia> "sse3" in Archspec.CPUTargets["broadwell"]
true

julia> "avx512" in Archspec.CPUTargets["haswell"]
false
source