buildlet: correct MinCPUPlatform name

Also, specify a valid CPU Platform for n2 VMs for OpenBSD.

See: https://cloud.google.com/compute/docs/instances/specify-min-cpu-platform#availablezones

For golang/go#48969

Change-Id: Id503227ad0fbb844e9eaa923b8b3ac7da591ee76
Reviewed-on: https://go-review.googlesource.com/c/build/+/356630
Trust: Alexander Rakoczy <[email protected]>
Run-TryBot: Alexander Rakoczy <[email protected]>
TryBot-Result: Go Bot <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>

Author: toothrot

buildlet/gce.go

@@ -75,7 +75,7 @@ func StartNewVM(creds *google.Credentials, buildEnv *buildenv.Environment, instN
 	minCPU := hconf.MinCPUPlatform
 	if hconf.IsContainer() {
 		if hconf.NestedVirt {
-			minCPU = "Cascade Lake" // n2 vms (which support NestedVirtualization) are either Ice Lake or Cascade Lake.
+			minCPU = "Intel Cascade Lake" // n2 vms (which support NestedVirtualization) are either Ice Lake or Cascade Lake.
 		}
 		if vm := hconf.ContainerVMImage(); vm != "" {
 			srcImage = "https://www.googleapis.com/compute/v1/projects/" + projectID + "/global/images/" + vm

dashboard/builders.go

@@ -237,8 +237,8 @@ var Hosts = map[string]*HostConfig{
 	},
 	"host-openbsd-amd64-64": &HostConfig{
 		VMImage:            "openbsd-amd64-64-190129a",
-		MinCPUPlatform:     "Intel Skylake", // for better TSC? Maybe? see Issue 29223. builds faster at least.
-		machineType:        "n2-highcpu-4",  // e2 instances do not support MinCPUPlatform or NestedVirt.
+		MinCPUPlatform:     "Intel Cascade Lake", // for better TSC? Maybe? see Issue 29223. builds faster at least.
+		machineType:        "n2-highcpu-4",       // e2 instances do not support MinCPUPlatform or NestedVirt.
 		buildletURLTmpl:    "https://storage.googleapis.com/$BUCKET/buildlet.openbsd-amd64",
 		goBootstrapURLTmpl: "https://storage.googleapis.com/$BUCKET/gobootstrap-openbsd-amd64-go1_12.tar.gz",
 		Notes:              "OpenBSD 6.4 with hw.smt=1; GCE VM is built from script in build/env/openbsd-amd64",