Andrey Lushnikov 1962b5be3c
test: make sure process killing logic works without ps on Linux (#22366)
The bare-bones `debian` distribution we use for testing doesn't have
`ps`. This patch switches to reading `/proc` file system directly on
Linux instead of relying on `ps`.

Performance measurements for the 20000 active processes on Debian Docker
container, tested on my M1 Max Mac:
- the `ps -eo pid,ppid,pgid` call + parsing takes 293ms
- the manual synchronous `/proc` traversal + parsing takes 326ms

So this is ~10% perf penalty.

Drive-by: rename `pgid` into `pgrp` so that it stands out from `pid`
(process ID) and `ppid` (parent process ID).
2023-04-12 13:16:42 -07:00
..
2022-04-06 14:57:14 -07:00