angular/packages/compiler-cli
George Kalpakas 5cee709266 fix(ngcc): do not spawn more processes than intended in parallel mode (#36280)
When running in parallel mode, ngcc spawns multiple worker processed to
process the various entry-points. The number of max allowed processes is
determined by the number of CPU cores available to the OS. There is also
currently an [upper limit of 8][1]. The number of active workers is in
turn inferred by the number of [task assignments][2].

In the past, counting the entries of `ClusterMaster#taskAssignments` was
enough, because worker processes were spawned eagerly at the beginning
and corresponding entries were created in `taskAssignments`.
Since #35719 however, worker processes are spawned lazily on an as
needed basis. Because there is some delay between
[spawning a process][3] and [inserting it][4] into `taskAssignments`,
there is a short period of time when `taskAssignment.size` does not
actually represent the number of spawned processes. This can result in
spawning more than `ClusterMaster#workerCount` processes.

An example of this can be seen in #36278, where the debug logs indicate
9 worker processes had been spawned (`All 9 workers are currently busy`)
despite the hard limit of 8.

This commit fixes this by using `cluster.workers` to compute the number
of spawned worker processes. `cluster.workers` is updated synchronously
with `cluster.fork()` and thus reflects the number of spawned workers
accurately at all times.

[1]: https://github.com/angular/angular/blob/b8e9a30d3b6/packages/compiler-cli/ngcc/src/main.ts#L429
[2]: https://github.com/angular/angular/blob/b8e9a30d3b6/packages/compiler-cli/ngcc/src/execution/cluster/master.ts#L108
[3]: https://github.com/angular/angular/blob/b8e9a30d3b6/packages/compiler-cli/ngcc/src/execution/cluster/master.ts#L110
[4]: https://github.com/angular/angular/blob/b8e9a30d3b6/packages/compiler-cli/ngcc/src/execution/cluster/master.ts#L199

PR Close #36280
2020-03-27 14:12:28 -07:00
..
integrationtest feat(ngcc): automatically clean outdated ngcc artifacts (#35079) 2020-01-31 17:02:44 -08:00
ngcc fix(ngcc): do not spawn more processes than intended in parallel mode (#36280) 2020-03-27 14:12:28 -07:00
src feat(compiler): add dependency info and ng-content selectors to metadata (#35695) 2020-03-24 14:21:42 -07:00
test feat(compiler): add dependency info and ng-content selectors to metadata (#35695) 2020-03-24 14:21:42 -07:00
BUILD.bazel build: provide full paths to ts_api_guardian_test_npm_package and ts_api_guardian_test (#36034) 2020-03-12 09:49:00 -07:00
index.ts refactor(compiler-cli): Move diagnostics files to language service (#33809) 2019-11-14 09:29:07 -08:00
package.json fix(compiler-cli): TypeScript peer dependency range (#36008) 2020-03-11 14:44:48 -04:00
tsconfig-build.json build: reference zone.js from source directly instead of npm. (#33046) 2019-11-06 00:48:34 +00:00
tsconfig.json perf(ivy): ngcc - only find dependencies when targeting a single entry-point (#30525) 2019-07-09 09:40:46 -07:00