Coverage for src / lilbee / runtime / cpu.py: 100%

1"""CPU concurrency policy for compute-bound parallelism. 

2 

3Use ``cpu_quota()`` to bound thread pools and asyncio semaphores that 

4schedule CPU-heavy work (chat inference, PDF rasterization, embedding, 

5tokenization). Capping at half of cpu_count keeps the asyncio main 

6thread scheduler share so the TUI stays responsive while a worker 

7storm is in flight. 

8 

9Do NOT use this for HTTP request concurrency: that lives under 

10``cfg.crawl_max_concurrent`` and is governed by remote-side rate 

11limits, not local CPU. 

12""" 

13 

14from __future__ import annotations 

15 

16import logging 

17import os 

18 

19log = logging.getLogger(__name__) 

20 

21_ENV_VAR = "LILBEE_CPU_QUOTA" 

22 

23 

24def cpu_quota() -> int: 

25 """Return the CPU concurrency cap; honors ``LILBEE_CPU_QUOTA`` override. 

26 

27 Default is ``max(1, os.cpu_count() // 2)``. The override accepts a 

28 positive integer; non-positive or unparseable values fall back to 

29 the default and a warning is logged once per call. 

30 """ 

31 override = os.environ.get(_ENV_VAR) 

32 if override is not None: 

33 try: 

34 value = int(override) 

35 if value > 0: 

36 return value 

37 except ValueError: 

38 pass # bad override falls through to the warning + default below 

39 log.warning( 

40 "Ignoring %s=%r: must be a positive integer; using default.", 

41 _ENV_VAR, 

42 override, 

43 ) 

44 return max(1, (os.cpu_count() or 2) // 2)