feature request: better build @com_googlesource_chromium_v8:build

[lambdai]

This target is internal spawn lots of tasks within. However, this target is considered as a single-core task from the view of bazel scheduler.

Generally speaking, when you run bazel build //source/exe:envoy with N cores, N tasks will be scheduled and at most N clang is running. However, if the running task contains @com_googlesource_chromium_v8:build, ~2N clang is running, and the peak ram usage could be huge.

A workaround: you may want to run bazel build @com_googlesource_chromium_v8//:build first, exhausting the cpu and ram.
When the above task is completed, you can run bazel build YOUR_REAL_TARGET using the build cache of the above v8 build.

[PiotrSikora]

The official Bazel support has been requested from the V8 team (https://bugs.chromium.org/p/v8/issues/detail?id=11234), and I don't think we can do too much until that's ready, since Envoy doesn't want to maintain custom BUILD files.

To address the issue at hand, perhaps we could provide an upper bound to limit the number of CPUs that ninja can spawn when building V8? Note that this will slow-down the whole process if V8 is scheduled to be build towards the end of the build, so the workaround you suggested might actually be the best thing to do.

[lambdai]

Thank you for the confirmation and for sharing the update at chromium! I don't think Envoy should invest too much.

[github-actions]

This issue has been automatically marked as stale because it has not had activity in the last 30 days. It will be closed in the next 7 days unless it is tagged "help wanted" or "no stalebot" or other activity occurs. Thank you for your contributions.

[PiotrSikora]

V8 team is working on this right now, and V8 v9.3 (branch cut on 7/15) should have native Bazel support.