tree 4ad50672b8a71b0afda6318090725f09a6201ea4
parent d4e13eae03ca22cde97a4af97373d15ecd454620
author jmmv <jmmv@google.com> 1550783447 -0800
committer Copybara-Service <copybara-worker@google.com> 1550783544 -0800

Lower Bazel's QoS service class to Utility on macOS.

Even though Bazel is an interactive tool, the operations it performs
are not time-critical and should not starve system services (started
by launchd, typically under the Utility class).  To mitigate this
problem, spawn the Bazel server under the Utility priority as well.

In internal tests at Google, we have seen that this vastly improves
build performance and overall system responsiveness when Bazel might
compete with system services such as openvpn or FUSE daemons.

Note that this is not a complete fix though.  We are still letting
the Bazel client run under the default class and the client still
uses execv in a couple of places.  First, in batch mode, and, second,
in "bazel run".  A possible fix for this would involve making the
Bazel client respawn itself under the right priority at the very
beginning but this has its own difficulties that should be looked
into separately.

Fixes https://github.com/bazelbuild/bazel/issues/7446 for the most
part.

RELNOTES: None.
PiperOrigin-RevId: 235054167