feat(memory): apply kernel memory tunables before memory-mode runs - #507
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not-matthias wants to merge 3 commits into
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feat(memory): apply kernel memory tunables before memory-mode runs#507not-matthias wants to merge 3 commits into
not-matthias wants to merge 3 commits into
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The sysctl read-then-write-with-sudo primitive is not walltime-specific; memory mode needs it too.
Tri-state (auto|on|off, CODSPEED_MEMORY_TUNABLES) controlling whether the runner stabilises kernel memory behaviour before memory-mode runs.
Disables transparent huge pages, sets vm.compaction_proactiveness, vm.swappiness and kernel.numa_balancing to 0, disables swap and drops the page cache, so benchmark repos no longer need a hand-written CI step. Applied only in CI by default, best-effort: a knob that cannot be set is a warning. swapoff is skipped on zram devices and whenever the swapped pages would not fit in available memory.
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Benchmark repos running
codspeed --mode memorycurrently need a hand-written CI step to stabilise kernel memory behaviour before measuring: disable THP, zerovm.compaction_proactiveness/vm.swappiness/kernel.numa_balancing,swapoff -a, and drop the page cache before each suite.The runner now does this itself at the start of every memory-mode execution.
Behaviour
--memory-tunables auto|on|off(envCODSPEED_MEMORY_TUNABLES), defaultauto= apply only when a CI run environment is detected, so developer machines are not silently mutated.swapoff -ais guarded: skipped on zram devices (it permanently resets theirdisksize) and whenever the swapped pages would not fit inMemAvailable.run()rather thansetup(), so the page cache is dropped before every suite and--skip-setupdoes not bypass it. The sysctl/THP writes are no-ops on later suites sinceensure_sysctlcompares before writing.Commits
refactor(executor): move linux_sysctl into executor helpers— pure move, the sysctl primitive is no longer walltime-specific.feat(cli): add --memory-tunables flagfeat(memory): apply kernel memory tunables before memory-mode runsVerification
cargo clippy --all-targetsclean,cargo test --release(pre-existing failures on this host are the sudo-requiring tests, identical onmain).Not running in CI, skipping kernel memory tunables; host THP unchanged.--memory-tunables=on: THPenabled/defragbecome[never],vm.compaction_proactiveness = 0,vm.swappiness = 0, and the swap guard correctly loggedLeaving swap enabled: swapped pages do not fit in available memory.