tree a08c5332892367e7f114d6c4af6c41331148d525
parent cf172301993250b31d532152bc8c834eaee8131e
author Oliver Newman <olivernewman@google.com> 1696963995 +0000
committer CQ Bot <fuchsia-internal-scoped@luci-project-accounts.iam.gserviceaccount.com> 1696963995 +0000

[engine] Limit number of active subprocesses

Previously the number of concurrent subprocess invocations launched by
`ctx.os.exec()` was unbounded, which could place a strain on the system.
Now there's effectively a pool of NumCPU+2 workers for running
subprocesses.

`ctx.os.exec()` returns immediately, but the underlying subprocess is
started asynchronously.

`ba -against main` showed no significant difference in the results of
the `ctx.os.exec()` benchmarks.

Change-Id: I76e4542249783c9a503f0f927e327e9f90f8bb04
Reviewed-on: https://fuchsia-review.googlesource.com/c/shac-project/shac/+/867979
Reviewed-by: Ina Huh <ihuh@google.com>
Commit-Queue: Oliver Newman <olivernewman@google.com>