cvmts: Allow specifying cgroup cpu period

probably limited utility wise but it's there now

cvmts/src/util/cgroup.ts

@@ -19,8 +19,8 @@ export class CGroupController {
 	WriteValue(key: string, value: string) {
 		try {
 			writeFileSync(path.join(this.cg.Path(), `${this.controller}.${key}`), value);
-		} catch(e) {
-			logger.error({error: e, controller_key: `${this.controller}.${key}`, value: value }, 'Failed to set CGroup controller value')
+		} catch (e) {
+			logger.error({ error: e, controller_name: this.controller, controller_key: `${this.controller}.${key}`, value: value }, 'Failed to set CGroup controller value');
 		}
 	}
 }
@@ -35,11 +35,11 @@ export class CGroup {
 	InitControllers(wants_cpuset: boolean) {
 		// Configure this "root" cgroup to provide cpu and cpuset controllers to the leaf
 		// QEMU cgroups. A bit iffy but whatever.
-		if(wants_cpuset) {
+		if (wants_cpuset) {
 			try {
 				writeFileSync(path.join(this.path, 'cgroup.subtree_control'), '+cpu +cpuset');
-			} catch(err) {
-				logger.error({error: err}, 'Could not provide cpuset controller to subtree');
+			} catch (err) {
+				logger.error({ error: err }, 'Could not provide cpuset controller to subtree. runOnCpus will not function.');
 				// just give up if this fails
 				writeFileSync(path.join(this.path, 'cgroup.subtree_control'), '+cpu');
 			}

cvmts/src/vm/qemu_launcher.ts

@@ -7,6 +7,7 @@ import { CGroup } from '../util/cgroup.js';
 export interface CgroupLimits {
 	cpuUsageMax?: number;
 	runOnCpus?: number[];
+	periodMs?: number;
 	limitProcess?: boolean;
 }
 
@@ -19,12 +20,19 @@ interface CGroupValue {
 function MakeValuesFromLimits(limits: CgroupLimits): CGroupValue[] {
 	let option_array = [];
 
+	// The default period is 100 ms, which matches cgroups2 defaults.
+	let periodUs = 100 * 1000;
+
+	// Convert a user-configured period to us, since that's what cgroups2 expects.
+	if(limits.periodMs)
+		periodUs = limits.periodMs * 1000;
+
 	if (limits.cpuUsageMax) {
 		// cpu.max
 		option_array.push({
 			controller: 'cpu',
 			key: 'max',
-			value: `${(limits.cpuUsageMax / 100) * 100000} 100000`
+			value: `${(limits.cpuUsageMax / 100) * periodUs} ${periodUs}`
 		});
 	}