tarantool / test-run / 9430486082

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master: 63%

Pull #435

github

Calculate parallel jobs based on available CPUs

We're going to enable new ARM64 runners in CI, where test-run is invoked
in a Docker container. At the same time, the runner is an LXD container
created by the service provider. In this circumstances, the Docker
container sees all the 128 online CPUs, but the runner may have
only some of them available (depending on the pricing plan).

Python 3.3+ has a function to determine available CPUs, so we can reduce
the parallelism to this value. We falls back to the online CPUs count on
Python < 3.3.

After this change, test-run follows a CPU affinity mask set by `taskset`
(and, I guess, by `numactl`).

The change is similar to replacing `nproc --all` to `nproc`.

The change only affects the default behavior, which can be overwritten
by passing the `--jobs` (or `-j`) CLI option or using the
`TEST_RUN_JOBS` environment variable.

Reported in https://github.com/tarantool/tarantool/pull/10102 (see a
discussion thread).

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