baselines

Tiering systems

This directory contains runtime configuration scripts and run scripts for baseline tiered memory management systems used in PACT evaluation.

Supported systems

System	Description
TPP	Transparent Page Placement - ASPLOS'23
NBT	Linux NUMA-Balancing-Tiering (v5.18)
Nomad	Non-exclusive Memory Tiering - OSDI'24
Colloid	Access Latency is Key! - SOSP'24
Memtis	Hardware-counter-driven tiered memory using PEBS for per-page access profiling and frequency-based migration - SOSP'23. memtis/
Soar/Alto	AOL-based Layered Tiering Orchestration and Static Object Allocation based on Ranking - OSDI'25. Paper · Code

Per-system directories

Each baseline lives in its own subdirectory with a kernel patch, a compile.sh, and a README describing the exact kernel tag and build steps:

System	Directory	Kernel base
TPP	tpp/	v5.15
NBT	nbt/	v5.18
Nomad	nomad/	5.13-rc6
Colloid-tpp	colloid-tpp/	v6.3
Memtis	memtis/	v5.15.19
Soar/Alto	soar-alto/	v6.3

Notes

• Colloid in our work refers to Colloid-tpp: we reproduce Colloid on the TPP path at Linux v6.3. (The original Colloid paper evaluates on NBT, NUMA Balancing Tiering.)
• These directories ship the kernel patches and build scripts. They do not include per-system workload run wrappers; boot the patched kernel and drive workloads with your own launcher (PACT's own runner is in ../).

Older-kernel build compatibility

TPP, Nomad and Memtis builds also apply common/libsubcmd-realloc.patch, upstream Linux commit 52a9dab6d892763b2a8334a568bd4e2c1a6fde66. It fixes the host-tool realloc(ptr, 0) use-after-free diagnosed by GCC 12 and newer. The patch retains its upstream authorship and the affected file's GPL-2.0 license. It does not change kernel tiering policy. The helper skips the fix when already present and stops if neither patch direction applies; it does not suppress compiler warnings. NBT and the Linux 6.3 baselines already contain this fix.

Colloid-tpp and Soar/Alto also apply common/colloid-build.patch, which removes an unused declaration in the tier-reset helper so CONFIG_WERROR=y builds succeed. It leaves the helper's operations and tiering policy unchanged.