CI: Increase parallelism without changing resource_class for faster b…

…uilds (#4448)

.circleci/config.yml

@@ -1,3 +1,7 @@
+# Disclaimer:
+# * Unless otherwise specified, assume `resource_class` and `parallelism` values are cherry-picked values that provided a reasonable enough build-duration-to-cost tradeoff at the time of choosing.
+# * There's too many variables (architecture types, CircleCI concurrency limitations, parallel pipeline runs, source code changes) to feel confident we've found a best-fit configuration.
+
 version: 2.1
 
 orbs:
@@ -507,7 +511,7 @@ jobs:
         type: string
     executor: << parameters.platform >>_medium
     working_directory: << pipeline.parameters.build_dir >>/project
-    parallelism: 4
+    parallelism: 32
     steps:
       - generic_build
       - generic_test:
@@ -540,7 +544,7 @@ jobs:
         type: string
     executor: << parameters.platform >>_large
     working_directory: << pipeline.parameters.build_dir >>/project
-    parallelism: 2
+    parallelism: 16
     environment:
       E2E_TEST_FILTER: "GO"
     steps:
@@ -574,7 +578,7 @@ jobs:
         type: string
     executor: << parameters.platform >>_medium
     working_directory: << pipeline.parameters.build_dir >>/project
-    parallelism: 2
+    parallelism: 10
     environment:
       E2E_TEST_FILTER: "EXPECT"
     steps: