1730253 - Run `./mach build` with lower process priority by default

Status: RESOLVED FIXED

(Firefox Build System :: General, enhancement)

Description

[Kelsey Gilbert [:jgilbert]]

It would be nice to keep machines snappy and responsive when they're otherwise all-core-saturated during builds.

Comment 1

[Kelsey Gilbert [:jgilbert]]

Attachment: Bug 1730253 - Add `./mach build --priority(=less)`.

Keys are idle/less/normal/more/high, like the named categories on
Windows.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/eed95dc1e702
Add `./mach build --priority(=less)`. r=firefox-build-system-reviewers,mhentges

Comment 3

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/eed95dc1e702

Comment 4

[Jon Bauman [:jbauman:]]

Despite having just pulled central and running a successful bootstrap, I'm getting failures when I try to run any mach gtest after this change:

$ MOZCONFIG=~/mozconfig-rel-opt ./mach gtest --list-tests
Error running mach:

    ['gtest', '--list-tests']

The error occurred in code that was called by the mach command. This is either
a bug in the called code itself or in the way that mach is calling it.
You can invoke |./mach busted| to check if this issue is already on file. If it
isn't, please use |./mach busted file gtest| to report it. If |./mach busted| is
misbehaving, you can also inspect the dependencies of bug 1543241.

If filing a bug, please include the full output of mach, including this error
message.

The details of the failure are as follows:

KeyError: "priority '' not in ['idle', 'less', 'normal', 'more', 'high']"

  File "/Users/jbauman/src/mozilla-unified/python/mozbuild/mozbuild/mach_commands.py", line 678, in gtest
    res = command_context._mach_context.commands.dispatch(
  File "/Users/jbauman/src/mozilla-unified/python/mach/mach/registrar.py", line 161, in dispatch
    return self._run_command_handler(handler, context, **kwargs)
  File "/Users/jbauman/src/mozilla-unified/python/mach/mach/registrar.py", line 107, in _run_command_handler
    result = fn(instance, **kwargs)
  File "/Users/jbauman/src/mozilla-unified/python/mozbuild/mozbuild/build_commands.py", line 169, in build
    if not _set_priority(priority, verbose):
  File "/Users/jbauman/src/mozilla-unified/python/mozbuild/mozbuild/build_commands.py", line 39, in _set_priority
    raise KeyError(f"priority '{priority}' not in {list(PRIO_CLASS_BY_KEY)}")

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