In November 2022 we seemed to increase parallelism from 2 and 3 to 10!
That is a huge load for these CI boxes, and does explain some of our
flakes.
We only run in parallel because some tests sleep, but it's diminishing
returns (GH runners have 4 VCPUs, 16GB RAM).
This reduces it so:
- Normal runs are -n 4
- Valgrind runs are -n 2
- Sanitizer runs are -n 3
If I use my beefy build box (64BG RAM) but reduce it to 4 CPUs:
Time for pytest -n 5:
Time for pytest -n 4:
Time for pytest -n 3:
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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