Sep 2026· Proceedings of the ACM SIGOPS 32nd Symposium on Operating Systems Principles· pp. 303-320· 0 citations· 83 references
TL;DR
Tierce, an observability substrate for colocated tiered memory, estimates workload-local exposed stall by measuring per-workload memory-level parallelism and scoring pages by realized access latency, and bounds LLC interference with explicit cache-way allocation.
Abstract
Tiered memory systems rely on hardware signals to estimate page criticality and decide which pages should remain in fast memory. Colocation corrupts these estimates at two points: shared LLC interference changes whether accesses reach memory, and downstream memory contention changes their stall cost. Both effects blend colocated workloads' behavior into shared page-criticality estimates, creating a fundamental observability gap for tiered memory management. We present Tierce, an observability substrate for colocated tiered memory. Tierce estimates workload-local exposed stall by measuring per-workload memory-level parallelism and scoring pages by realized access latency. It bounds LLC interference with explicit cache-way allocation. Across 8 colocated pairs that run four foreground workloads against a bandwidth-intensive and a bursty, phase-varying co-runner, Tierce outperforms PACT, the best prior art, on every pair, by 2.2% to 12.6%.
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