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CPU Isolation and Execution

To ensure stable real-time performance, use scripts/isolate_cpus.py (or the thin wrapper scripts/isolate_cpus.bash) to constrain system services (system.slice, user.slice, init.scope) away from critical OpenISAC cores.

All setup/run commands require root privileges (sudo):

Terminal window
cd ~/OpenISAC
chmod +x scripts/isolate_cpus.py scripts/isolate_cpus.bash
sudo ./scripts/isolate_cpus.py --help

Default isolation policy (YAML-driven)

Terminal window
cd build
# Ensure BS.yaml / UE.yaml exist (copy from config/ as needed)
sudo ../scripts/isolate_cpus.py

The script first asks which role this machine has:

  1. BS only — reads BS.yaml
  2. UE only — reads UE.yaml
  3. BS + UE — reads both (same-host dual stack)

It then reserves only the most scheduling-sensitive cores from YAML:

  • USRP sample TX/RX threads (e.g. BS TX, UE rx_proc, uplink TX/RX ingest)
  • main_cpu_core
  • BS monostatic sensing rx_cpu_core (sample ingest only)

OFDM modulation/demodulation, LDPC, UDP, sensing processing, and workers are not reserved by default so they can share noisier system cores.

Non-interactive / scripted:

Terminal window
sudo ../scripts/isolate_cpus.py --role bs
sudo ../scripts/isolate_cpus.py --role ue
sudo ../scripts/isolate_cpus.py --role both
sudo ../scripts/isolate_cpus.py show-plan --role bs   # dry-run

Custom application CPU set (manual override)

Terminal window
sudo ./scripts/isolate_cpus.py 4          # App uses 0-3
sudo ./scripts/isolate_cpus.py 8-15       # App uses 8-15
sudo ./scripts/isolate_cpus.py 0,2,4,6    # App uses explicit core list

State is saved to /tmp/isolate_cpus_app.conf (reserved cores) and /tmp/isolate_cpus_state.json (full plan).

CPU binding priority when cores are limited

  • Reserve one dedicated core for the main thread first.
  • Then prioritize the TX/RX real-time threads.
  • Then OFDM modulation/demodulation threads.
  • Leave LDPC / UDP / sensing-processing on system cores when possible.

Run application (process may use all CPUs)

Terminal window
cd build
sudo ../scripts/isolate_cpus.py run ./BS
sudo ../scripts/isolate_cpus.py run ./UE
  • run sets process AllowedCPUs to all logical CPUs (reserved ∪ system).
  • Critical threads stay on reserved cores via YAML affinity; non-critical threads may schedule on system cores.
  • Use run --app-only ./BS only if you want the old whole-process reserved-only behavior.

Note: Always launch via sudo ../scripts/isolate_cpus.py run ... after isolation is set. Direct execution from a restricted user slice may fail to use reserved cores.

Reset configuration (optional)

Terminal window
sudo ./scripts/isolate_cpus.py reset

This removes the isolation settings and restores system slices to all CPUs.