resctrl_arch...ycles_lat_fn(9)

✨ NAME ✨

okay so this is from the Kernel API Manual, and the manual page is filed under the truncated little handle resctrl_arch...ycles_lat_fn(9). The actual main character is resctrl_arch_measure_cycles_lat_fn — it measures cycle latency to read pseudo-locked memory 🎀

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🦋 SYNOPSIS 🦋

int resctrl_arch_measure_cycles_lat_fn (void *_plr );

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🌸 ARGUMENTS 🌸

• _plr — the pseudo-lock region to measure, bestie. That's the thing we're checking on 💅

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💖 DESCRIPTION 💖

ngl, there is no deterministic way to test if a memory region is cached. Like, none. So one way is to measure how long it takes to read the memory — the speed of access is a good way to learn how close to the cpu the data was ✨

Even more iconic: if the prefetcher is disabled and the memory is read at a stride of half the cache line, then a cache miss will be easy to spot, since the read of the first half would be significantly slower than the read of the second half 👑

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⭐ RETURN ⭐

• 0 — waiter on waitqueue will be woken on completion. slay 💫

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🫶 SEE ALSO 🫶

• Kernel file ./arch/x86/kernel/cpu/resctrl/pseudo_lock.c
• resctrl_arch_get_prefetch_disable_bits(9)
• resctrl_arch_pseudo_lock_fn(9)

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and that's the vibe check, bestie 💜 this cutie lives in the source tree at ./arch/x86/kernel/cpu/resctrl, dated October 2026, and signs off as resctrl_arch...ycles_lat_fn(9) — mwah 💋🎀