ananicy-cpp

C++ auto-nice daemon that applies process rules for CPU, I/O, and affinity

TLDR

Dump parsed rules currently loaded

$ ananicy-cpp dump rules

Dump configured process types

$ ananicy-cpp dump types

Dump rules as JSON

$ ananicy-cpp dump rules --json

Validate a rules file without applying it

$ ananicy-cpp parse [path/to/file.rules]

Enable and start the systemd service

$ sudo systemctl enable --now ananicy-cpp.service

ananicy-cpp is a C++ rewrite of the Ananicy auto-nice daemon. It watches processes and applies community or local rules that set niceness, CPU scheduler, I/O class, OOM score, cpuset affinity, and optional cgroup placement. The goal is the same as Ananicy: keep interactive programs snappy while background jobs (compilers, indexers) stay polite, with much lower CPU and memory use than the original Python daemon.Rules live under /etc/ananicy.d (or ANANICY_CPP_CONFDIR) in `.rules` files. Types (`.types`) and cgroups (`.cgroups`) avoid repeating the same settings. Global options are in /etc/ananicy.d/ananicy-cpp.conf (or ANANICY_CPP_CONF). Original Ananicy rule sets can be copied into that directory as a drop-in starting point.

CONFIGURATION

Global settings use `key=value` lines. Common keys include check_freq (full scan interval, default 60 seconds), apply_nice, apply_sched, apply_ionice, apply_oom_score_adj, apply_cpuset, cgroup_load, type_load, rule_load, and loglevel.A rule is one JSON object per line:

$ {"name": "gcc", "nice": 19, "sched": "batch", "ioclass": "idle"}
{"name": "my-game", "cpuset": "performance-cores", "nice": -5}

Named cpuset aliases such as big-cores, little-cores, x3d-cache, llc-N, and node-N are resolved from detected CPU topology.

COMMANDS

dump rules [--json]

Print currently parsed rules (optionally as JSON).

dump types

Print configured process types.

parse file.rules

Parse and validate a rules file without applying it.

INSTALL

sudo pacman -S ananicy-cpp

nix profile install nixpkgs#ananicy-cpp

CAVEATS

The daemon typically runs as root via systemd. cgroup placement generally requires root (there is no dedicated capability). cgroup v1 is recommended for full CPUQuota support. Realtime policies (fifo, rr) can starve the rest of the system if misused. I/O class and ionice only apply with the CFQ I/O scheduler.

HISTORY

Ananicy was written by Nefelim4ag in Python. ananicy-cpp reimplements the same rule model with an event-based C++ scanner so RAM stays in kilobytes and CPU use is near idle.

RESOURCES

Source code