mirror of
https://github.com/firestar5683/StarPilot.git
synced 2026-11-09 22:13:43 +08:00
dirwin31
93 lines
3.2 KiB
Python
93 lines
3.2 KiB
Python
"""Runs the car renderer on core 7 at the lowest priority.
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Safeguards:
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- SCHED_IDLE, so the realtime driving and driver-monitoring models on core 7
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always preempt it. Core 6 is no longer an option: since 2026-10-07
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(c01f815736) selfdrive/ui/ui.py runs the comma UI there next to camerad, which
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left a SCHED_IDLE renderer waiting ~70% of the time with the core 98% busy.
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- Every renderer thread is placed, including ones the graphics driver starts later.
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- Parked, power saving turns cores 4-7 off. The pin is re-applied every
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PLACEMENT_CHECK_INTERVAL seconds once core 7 is back, like selfdrive/ui/ui.py.
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"""
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from __future__ import annotations
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import os
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from collections.abc import Callable
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from typing import Any
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RENDER_CORE = 7
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PLACEMENT_CHECK_INTERVAL = 1.0 # s
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FALLBACK_NICE = 10 # if SCHED_IDLE is unavailable
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def _thread_ids() -> list[int]:
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try:
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return [int(tid) for tid in os.listdir("/proc/self/task")]
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except OSError:
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return [0]
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def _core_online(core: int) -> bool:
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if core == 0:
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return True
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try:
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with open(f"/sys/devices/system/cpu/cpu{core}/online") as f:
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return f.read().strip() == "1"
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except OSError:
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return False
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class RendererPlacement:
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"""Keeps every renderer thread SCHED_IDLE on RENDER_CORE while that core is online."""
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def __init__(self, core: int = RENDER_CORE, report: Callable[[dict[str, Any]], None] | None = None,
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thread_ids: Callable[[], list[int]] = _thread_ids, core_online: Callable[[int], bool] = _core_online):
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self.core = core
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self.report = report or (lambda _event: None)
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self.thread_ids = thread_ids
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self.core_online = core_online
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self.next_check = 0.0
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self.pinned = False
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def start(self) -> None:
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"""Call first, before any thread exists, so later threads inherit the policy."""
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if not hasattr(os, "sched_setaffinity"):
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self.report({"event": "cpu_placement", "pinned": False, "reason": "no CPU affinity on this platform"})
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self.next_check = float("inf")
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return
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inherited = sorted(os.sched_getaffinity(0))
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policy = "idle"
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try:
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os.sched_setscheduler(0, os.SCHED_IDLE, os.sched_param(0))
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except (AttributeError, OSError):
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policy = f"nice{FALLBACK_NICE}"
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try:
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os.nice(FALLBACK_NICE)
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except OSError:
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policy = "default"
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self.report({"event": "cpu_placement", "policy": policy, "inherited_cores": inherited, "core": self.core})
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self.maintain(0.0)
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def maintain(self, now: float) -> None:
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if now < self.next_check:
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return
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self.next_check = now + PLACEMENT_CHECK_INTERVAL
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if not self.core_online(self.core):
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if self.pinned:
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self.report({"event": "cpu_placement", "pinned": False, "reason": f"core {self.core} offline"})
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self.pinned = False
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return
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target = {self.core}
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changed = False
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for tid in self.thread_ids():
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try:
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if os.sched_getaffinity(tid) != target:
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os.sched_setaffinity(tid, target)
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changed = True
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except OSError:
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pass # the thread exited
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if changed or not self.pinned:
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self.report({"event": "cpu_placement", "pinned": True, "cores": sorted(os.sched_getaffinity(0))})
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self.pinned = True
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