hesela.devDULO
DULO is a buffer-cache replacement scheme that combines recent access history with disk-block sequentiality to shape the requests reaching a hard disk.
At comparable recency, DULO favors retaining scattered blocks and evicting longer block sequences, aiming to leave more sequential work for the disk. Sequences depend on disk placement and recent accesses, not merely neighboring application addresses. [1]
Its simulation compares against CLOCK under the label LRU. The Linux 2.6.11 prototype is an adaptation within the inactive list, not an exact implementation of the standalone design. [1]
Comparison requires the actual victim-selection rules and backend workload, not a policy label alone. CAR independently describes CLOCK as an LRU approximation. [2]
Relations
Limitations
- Pure random input provides no sequential requests for the policy to preserve. [1]
Citations
- Jiang et al. DULO: An Effective Buffer Cache Management Scheme to Exploit Both Temporal and Spatial Locality. FAST 2005, sections 3, 4.1.1, 4.2.2.
- Bansal and Modha. CAR: Clock with Adaptive Replacement. FAST 2004, sections I-II.
Sources & caveats
- Historical HDD simulations and an adapted kernel prototype, not a modern SSD or current-Linux performance claim. [1]
- Source review only; no DULO code, private traces, timing benchmark or replication is supplied.