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Gauntlet Tests

The gauntlet expands each #[ktstr_test] into a matrix of test × topology_preset variants. The test definition controls which cells of the matrix it populates.

Controlling topology coverage

Topology constraints in #[ktstr_test] filter which gauntlet presets a test runs on. See Topology Constraints for the full attribute table and Topology Presets for the preset list.

Worked example

A test with min_llcs = 2, requires_smt = true, and default max_numa_nodes = 1 against the preset table:

  • tiny-1llc (1 LLC): excluded — below min_llcs
  • All non-SMT presets (tiny-2llc, odd-*, *-nosmt): excluded — requires_smt
  • near-max-llc (15 LLCs): excluded — above default max_llcs = 12
  • max-cpu (252 CPUs, 14 LLCs): excluded — above default max_cpus = 192 (also above default max_llcs = 12)
  • All numa* presets: excluded — above default max_numa_nodes = 1

Result: 6 of 24 presets survive (smt-2llc, smt-3llc, medium-4llc, medium-8llc, large-4llc, large-8llc). On aarch64, none survive — all aarch64 presets lack SMT.

Total variant count

The total number of gauntlet variants for a test is:

valid_presets × resolved_kernels

A test with 8 valid presets produces 8 gauntlet variants under a single-kernel run; passing two kernels (--kernel A --kernel B) doubles that to 16. The kernel dimension is contributed by cargo ktstr test / coverage / llvm-cov at the CLI surface (zero or one resolved kernels keeps the historical 3-segment name shape gauntlet/{name}/{preset}; two or more expands the gauntlet across kernels with an extra {kernel_label} segment). See Multi-kernel: kernel as a gauntlet dimension.

Tests that skip gauntlet

  • Entries with host_only = true never produce gauntlet variants (no VM to vary topology on). They also skip the kernel-dim multiplication under multi-kernel runs: a host_only test lists and runs once regardless of KTSTR_KERNEL_LIST cardinality, since a host-side test never observes the kernel directory and N copies of identical work would carry no signal. See host_only for how that flag is set, and Multi-kernel: kernel as a gauntlet dimension for the kernel-suffix dispatch contract.
  • Tests whose names start with demo_ are ignored by default. Their gauntlet variants are also ignored (all gauntlet variants are ignored).

Cross-references