heapred

heapred measures live glibc-visible heap-state compressibility by freezing a target process at capture times, reconstructing the live heap from an append-only committed allocation log, serializing a canonical heap stream, and compressing that stream with ZPAQ

Components

• libheapred_preload.so: C interposer loaded through LD_PRELOAD.
• heapred: C++ collector CLI.

Build

Dependencies: Linux, glibc, gcc (including g++), awk, make, and bash

make
# make test

CLI

./heapred run --times 1s,2s --methods 1,4 -- ./target args
./heapred run --every 500ms --methods 4 -- ./target args
./heapred analyze run/snapshots/0001_t1.000000000 --methods 1,4
./heapred report run

Snapshot Layout

Each snapshot directory contains:

• snapshot.json
• events.state.json
• blocks.jsonl
• heap-stream.bin
• heap-stream.sha256
• compression/zpaq-<method>.json

Heap Stream

Blocks are ordered by ascending alloc_id and encoded as:

1. 8-byte little-endian size
2. exactly size payload bytes

No pointer/address metadata is included in the canonical stream.

Limitations (at least for now)

• Only glibc-wrapped heap allocations are measured.
• Direct mmap performed by the application is excluded.
• Static binaries are unsupported.
• Snapshot time is the first frozen state at or after requested time (not instruction-exact).
• Compression results depend on encoding and selected compressor method.

License

This is free software available under the ISC License. Read the ./LICENSE file completely.