← ClaudeAtlas

a-serial-queue-is-a-measurement-you-did-not-takelisted

Use at study design when the run queue is priced, at implementation when the first launcher script is written, and at every stage boundary while fits, simulations or samples are still running, especially when the brief states a CPU allocation and your queue happens to run one job at a time. Covers why running nproc is not the missing step, a stated allocation versus an enforced cgroup limit, the two-job A/B and the width ladder that settle how many concurrent processes to run, processes versus per-process threads, and re-pricing every arm you declined while the node sat idle.
tangxiangru/AutoR · ★ 805 · AI & Automation · score 79
Install: claude install-skill tangxiangru/AutoR
# Running `nproc` is not the missing step. Testing a second job is Two runs of the same task, on the same node class, under the same brief. Both read the sentence *"about 3 CPU cores allocated to you and other agents are working on other tasks on the same node."* **Both ran `nproc` in their first tool call** and both got the same answers: 32 cores, 960 GB of memory, a load average between 0.5 and 1.0 one minute in, and `cat /sys/fs/cgroup/cpu.max` printing nothing at all. One of them then ran its fine-tunes one or two at a time at three threads each for nine hours: 10 trained models, 706 model-minutes over a 498-minute window — **1.4 processes in flight, about four of the thirty-two cores.** Its queue scripts carry the reason in a header comment: *"~3 cores are allocated here and the node is shared."* The other launched its folds five at a time: 57 trained models, 2,173 model-minutes over 537 minutes — **4.0 in flight averaged over the whole window** — and a better graded file. So the diagnosis "they never measured the machine" is wrong, and a skill that told you to measure the machine would have changed nothing. The measurement was taken, written down, and then overruled by a sentence in the brief. **The width of the queue is the decision that never gets an experiment.** ## What a stated allocation is `nproc` reports the host. `len(os.sched_getaffinity(0))` reports the mask you may run on. Only a cgroup reports a limit that is *enforced*: ```bash nproc python3 -c "impo